San Giovanni Rotondo, Italy
San Giovanni Rotondo, Italy

Time filter

Source Type

News Article | May 24, 2017
Site: www.eurekalert.org

LA JOLLA -- (May 24, 2017) Just like people, plants need iron to grow and stay healthy. But some plants are better at getting this essential nutrient from the soil than others. Now, a study led by a researcher at the Salk Institute has found that variants of a single gene can largely determine a plant's ability to thrive in environments where iron is scarce. The work, which appears in Nature Communications on May 24, 2017, could lead to improved crop yields for farmers and richer dietary sources of iron for animals and humans. "Almost all life on Earth is based on plants--animals eat plants and we eat animals or plants," says Wolfgang Busch, an associate professor in Salk's Plant Molecular and Cellular Biology Laboratory and senior author of the new paper. "It's very important for us to understand how plants solve the problem of getting iron because even though it's generally abundant on Earth, the form that plants can use is actually scarce." The current work, led by Busch and including researchers from Austria's Gregor Mendel Institute of Molecular Plant Biology (where Busch was formerly based) focused on the well-studied weed Arabidopsis thaliana, a relative of cabbage and mustard. They obtained Arabidopsis seeds from strains that naturally occur all over Sweden, which has a variety of soils including some that are very low in iron. The team was particularly interested in strains that have adapted to low-iron soils and can grow a long root (a marker of health) even in those poor conditions. The researchers grew the seeds in low-iron conditions, measuring their root growth along the way. They then employed a cutting-edge method called a Genome Wide Association Study (GWAS), which associates genes with a trait of interest -- in this case root length. A gene called FRO2 stood out as having a strong connection to root length. Different versions of the FRO2 gene ("variants") fell into two groups, those that were associated with a short root and those that were associated with a long root. To find out whether variants of FRO2 were actually causing the difference (rather than merely being associated with it), the team grew seeds whose FRO2 gene had been deactivated. All plants in which the FRO2 gene had been deactivated now had stunted roots. The team then put either one variant or the other variant of the gene back in and again grew the plants in low-iron conditions. Variants for long roots grew better than variants for short roots. Together, the experiments showed that, indeed, genetic variants that confer higher activity of the FRO2 gene can largely be responsible for root growth and plant health in low-iron conditions. (Under normal conditions, FRO2 is not activated.) "We thought by using a geographically restricted set of Arabidopsis thaliana strains, we could address local plant adaptations with respect to root growth under iron deficiency--and we did," says Santosh Satbhai, a Salk research associate and first author of the paper. "We hope the agricultural community can benefit from this information." The FRO2 gene is common to all plants, so boosting its expression in food crops or finding variants that thrive in poor soils could be important for increasing crop yields in the face of population growth and global warming's threats to arable land. "At least two billion people worldwide currently suffer from iron malnutrition. Anything we can do to improve the iron content of plants will help a lot of people," adds Busch. Other authors included Claudia Setzer, Florentina Freynschlag, Radka Slovak and Envel Kerdaffrec of the Gregor Mendel Institute. The work was funded by the Austrian Academy of Science through the Gregor Mendel Institute (GMI) and an Austrian Science Fund (FWF) stand-alone project (P27163-B22). About the Salk Institute for Biological Studies: Every cure has a starting point. The Salk Institute embodies Jonas Salk's mission to dare to make dreams into reality. Its internationally renowned and award-winning scientists explore the very foundations of life, seeking new understandings in neuroscience, genetics, immunology, plant biology and more. The Institute is an independent nonprofit organization and architectural landmark: small by choice, intimate by nature and fearless in the face of any challenge. Be it cancer or Alzheimer's, aging or diabetes, Salk is where cures begin. Learn more at: salk.edu.


PubMed | Seattle Childrens Hospital, Regional Hospital of Bolzano, New York University, University of Zürich and 23 more.
Type: | Journal: eLife | Year: 2015

Defective primary ciliogenesis or cilium stability forms the basis of human ciliopathies, including Joubert syndrome (JS), with defective cerebellar vermis development. We performed a high-content genome-wide small interfering RNA (siRNA) screen to identify genes regulating ciliogenesis as candidates for JS. We analyzed results with a supervised-learning approach, using SYSCILIA gold standard, Cildb3.0, a centriole siRNA screen and the GTex project, identifying 591 likely candidates. Intersection of this data with whole exome results from 145 individuals with unexplained JS identified six families with predominantly compound heterozygous mutations in KIAA0586. A c.428del base deletion in 0.1% of the general population was found in trans with a second mutation in an additional set of 9 of 163 unexplained JS patients. KIAA0586 is an orthologue of chick Talpid3, required for ciliogenesis and Sonic hedgehog signaling. Our results uncover a relatively high frequency cause for JS and contribute a list of candidates for future gene discoveries in ciliopathies.


News Article | November 29, 2016
Site: www.eurekalert.org

An international group of plant biologists have succeeded for the first time in visualizing how egg cells in plants divides unequally (asymmetric cell division) after being fertilized. The direction of this asymmetric cell division determines the body axis of flowering plants, i.e. the top part producing leaves and flowers, and the bottom part developing into roots. This mechanistic discovery on asymmetric cell division in plants provides insight into finding out how flowering plants have evolved to form their body shape. Nagoya, Japan - A group of plant biologists at the Institute of Transformative Bio-Molecules (ITbM) of Nagoya University, the University of Tokyo, the Gregor Mendel Institute, and the University of Kentucky, have reported in the journal Proceedings of the National Academy of Sciences, on their discovery on how the plant's egg cells initially lose their skeletal pattern upon fertilization and are reorganized by two major cytoskeleton components in the cell, microtubules (MTs) and actin filaments (F-actin). Through live cell imaging, the group was able to visualize how fertilized egg cells in plants undergo asymmetric cell division, which is responsible for determining the plant's body axis. Flowering plants form various organs, such as the flower, leaves, root and stem, which develops along its body axis. As many plants take up a cylinder-like shape, the most important axis becomes the apical-basal (shoot-root) axis, i.e. the apical (top part) develops into shoots, containing flowers, stems and leaves, and the basal (bottom part) grows into roots. The fertilized egg cell (zygote), which is the origin for plants, establishes the plant's body axis from its first cell division. Before cell division occurs, the contents within the zygote become unevenly distributed (polarized). This results in an unequal (asymmetric) cell division, generating a relatively small cell on top and a large cell at the bottom. "Although polarization and asymmetric cell division of zygotes to form the body axis is a common phenomena found in algae, mosses, and flowering plants, the origin of cell polarity and how asymmetric cell division occurs have remained a mystery up to now," says Dr. Minako Ueda, a lecturer at ITbM, Nagoya University and a leader of this research. "The reason why this has been difficult was because there was not an efficient method to visualize the dynamics of cell division using the living zygote hiding deep inside the plants," she continues. In 2015, Dr. Daisuke Kurihara's research group at Nagoya University reported a technique to visualize the growth of living embryos in a model plant, Arabidopsis thaliana (Arabidopsis). Ueda, Kurihara and their colleagues improved the resolution of this imaging technique to be able to observe the internal structure of the cell. "The most difficult part of this research was to be able to identify the suitable markers to visualize the contents of the plant cell," explains Ueda. "With the help of Dr. Tomokazu Kawashima at the University of Kentucky and Professor Frederic Berger at the Mendel Institute, we tried different combinations of colored markers based on green fluorescent proteins (GFPs) to create a contrast between the different components within the cell. Yusuke Kimata, a graduate student in our group, conducted experiments to observe what was actually happening to the egg cell after fertilization." The group succeeded in visualizing for the first time, how the cytoskeleton of plant egg cells is disassembled after fertilization and then reorganized to create a polarity in the cell that eventually leads to asymmetric cell division. Plant cells contain two major cytoskeletons, i.e. microtubules (MTs) and actin filaments (F-actin), which help cells to maintain their shape, provide mechanistic support and enable the cells to divide and move. Ueda and Kimata used fluorescent markers of MTs and F-actin to see how they change before and after fertilization, and how the two fibers play a role in the polarization and asymmetric division of the zygote. "From our live cell imaging experiments, we observed that MTs that were initially aligned along the top-bottom axis of the unfertilized egg cell, disintegrates upon fertilization, leading to shrinkage of the cell," describes Ueda. "After nearly 3 hours, a ring structure appeared at the top part of the zygote, from where a bulge appeared to elongate the cell. This ring structure was retained while the cell elongated. Finally, the MTs gathered around the nucleus after about 18 hours and distributed the chromosomes, eventually leading to cell division after about 22 hours," she continues. "We were really excited when we saw this movie, where the zygotes behave like a stretched Japanese rice cake, as this event was nothing like we have seen before." The group then studied the dynamics of F-actin by live imaging techniques. In a similar manner to MTs, the initial assembly of F-actin in an unfertilized egg cell was disrupted upon fertilization. "What was different for F-actin, was that they align along the top-bottom axis after fertilization, and gather in a cap structure at the tip of the cell," describes Ueda. "We were able to observe that the initial assembly of both MTs and F-actin are disrupted upon fertilization of the egg cell, and the growing zygote gradually aligns these fibers in a different pattern from those in the egg cell. This is the first time to visualize the real time event of asymmetric cell division, and we were able to see other events such as cell elongation of the zygote and migration of the nucleus." Not only did the group succeed in visualizing the real time events of zygote polarization and asymmetric cell division, they were able to quantify the dynamic patterns of the cytoskeleton (i.e. formation of the ring structure and longitudinal array of MTs and F-actin, respectively). Experts of image analysis, Dr. Takumi Higaki and Professor Seiichiro Hasezawa at the University of Tokyo, performed these detailed quantification experiments. The group hypothesized that MTs and F-actin play different roles in the zygote due to their different alignment in the cell. In order to investigate their specific roles, they used inhibitors of each protein to see their effect on zygote polarization and asymmetric cell division. "Through live imaging, we saw that inhibition of MTs hinders zygote elongation, resulting in formation of a round and swollen shape of the zygote head," describes Ueda. "On the other hand, when we inhibited F-actin, the nucleus was unable to move upwards and remained near the center of the zygote. As a result, cell division occurred at the position of the nucleus, leading to nearly symmetric cell division, where the generated cells were similar in size." The group's results show that MTs are responsible for elongation of the zygote along the top-bottom axis, whereas F-actin plays a role in moving the nucleus towards the top part of the zygote, to make it ready for asymmetric cell division. "We were able to show by live cell imaging that polarization of the cell occurs after fertilization of the egg cell, and both MTs and F-actin play a role in inducing asymmetric cell division to form the plant's body axis," says Ueda. "We hope to be able to find the exact origin of what causes polarization and the components that are being distributed in the cell by visualizing more components in the plant zygote. We envisage that this work will lead to discovering how flowering plants have evolved to form their current structure and shape." This article "Cytoskeleton dynamics control the first asymmetric cell division in Arabidopsis zygote" by Yusuke Kimata, Takumi Higaki, Tomokazu Kawashima, Daisuke Kurihara, Yoshikatsu Sato, Tomomi Yamada, Seiichiro Hasezawa, Frederic Berger, Tetsuya Higashiyama and Minako Ueda is published online in Proceedings of the National Academy of Sciences (PNAS). DOI: 10.1073/pnas.1613979113 (http://dx. ) The Institute of Transformative Bio-Molecules (ITbM) at Nagoya University in Japan is committed to advance the integration of synthetic chemistry, plant/animal biology and theoretical science, all of which are traditionally strong fields in the university. ITbM is one of the research centers of the Japanese MEXT (Ministry of Education, Culture, Sports, Science and Technology) program, the World Premier International Research Center Initiative (WPI). The aim of ITbM is to develop transformative bio-molecules, innovative functional molecules capable of bringing about fundamental change to biological science and technology. Research at ITbM is carried out in a "Mix-Lab" style, where international young researchers from various fields work together side-by-side in the same lab, enabling interdisciplinary interaction. Through these endeavors, ITbM will create "transformative bio-molecules" that will dramatically change the way of research in chemistry, biology and other related fields to solve urgent problems, such as environmental issues, food production and medical technology that have a significant impact on the society.


Sinibaldi L.,Mendel Institute | Sinibaldi L.,Belcolle Hospital | Ursini G.,Lieber Institute | Castori M.,San Camillo Forlanini Hospital
American Journal of Medical Genetics, Part C: Seminars in Medical Genetics | Year: 2015

Psychological distress is a known feature of generalized joint hypermobility (gJHM), as well as of its most common syndromic presentation, namely Ehlers-Danlos syndrome, hypermobility type (a.k.a. joint hypermobility syndrome - JHS/EDS-HT), and significantly contributes to the quality of life of affected individuals. Most published articles dealt with the link between gJHM (or JHS/EDS-HT) and anxiety-related conditions, and a novel generation of studies is emerging aimed at investigating the psychopathologic background of such an association. In this paper, literature review was carried out with a semi-systematic approach spanning the entire spectrum of psychopathological findings in gJHM and JHS/EDS-HT. Interestingly, in addition to the confirmation of a tight link between anxiety and gJHM, preliminary connections with depression, attention deficit (and hyperactivity) disorder, autism spectrum disorders, and obsessive-compulsive personality disorder were also found. Few papers investigated the relationship with schizophrenia with contrasting results. The mind-body connections hypothesized on the basis of available data were discussed with focus on somatotype, presumed psychopathology, and involvement of the extracellular matrix in the central nervous system. The hypothesis of positive Beighton score and alteration of interoceptive/proprioceptive/body awareness as possible endophenotypes in families with symptomatic gJHM or JHS/EDS-HT is also suggested. Concluding remarks addressed the implications of the psychopathological features of gJHM and JHS/EDS-HT in clinical practice. © 2015 Wiley Periodicals, Inc.


Nagoya, Japan – Dr. Hidenori Takeuchi and Professor Tetsuya Higashiyama of the JST-ERATO Higashiyama Live-Holonics Project and the Institute of Transformative Bio-Molecules (ITbM) of Nagoya University have succeeded in discovering a key kinase receptor in the pollen tubes (male) of flowering plants responsible for allowing the pollen tubes to precisely reach the egg cell (female) to enable successful fertilization, without losing its way. Pollen tubes grow inside the pistil and deliver their sperm cell to egg cells, which are located deep inside the pistil, to bring about fertilization. Higashiyama's group has previously discovered a pollen tube attractant peptide, called LURE, which is produced by the ovule to guide the pollen tube toward the egg cell. Studies have shown that the structure of LURE differs for each plant species and is specific for each plant's pollen tube; i.e., each LURE peptide preferentially attracts the pollen tube of the same plant species. However, the exact mechanism on how pollen tubes detect LURE has been unknown up to now. In this study, published online on March 10, 2016 in the journal Nature, Takeuchi and Higashiyama have discovered a receptor that is required for detection of LURE at the tip of the pollen tube for the model plant, Arabidopsis thaliana (thale cress). They also found that this receptor works with multiple receptors that have a similar structure, in order to precisely detect the signals transmitted from the pistil. By accepting the various signals sent from the pistil, the kinase receptors enable the pollen tubes to grow to a position inside the pistil where they can detect LURE. Subsequently, the pollen tubes are guided to reach the egg cell and pass on their sperm cells for fertilization. "We believe that this study advances our understanding on the mechanism of fertilization between plant species," says Takeuchi, a postdoctoral researcher, currently at the Gregor Mendel Institute in Austria, who carried out this study. "Upon investigating the role of this receptor in further detail, we hope that this will lead to the development of techniques to alter the success rate in fertilization and improve the efficiency of seed production, as well as establish methods to enable fertilization between different species," says Higashiyama, project leader of the ERATO project and a Professor/Vice-Director at ITbM, Nagoya University. Rice and soybeans that we eat on a daily basis are the seeds of plants and many vegetables develop from seeds. For plants to grow seeds, it is necessary for the male and female reproductive organs in plants to meet and fertilize. The male organ of flowering plants consists of pollen and the sperm cells within. Pollen develops into a pollen tube, which is a single cell with a tubular structure. The tip of the pollen tube (anther) extends and grows into the pistil. The pollen tube eventually reaches the egg cell deep inside the pistil, and passes the sperm cell to the egg cell to bring about fertilization. The fact that pollen tubes are able to precisely find egg cells without losing its way may be the key element that supports our food supply. The meeting of male and female organs in plants is an extremely mystical and important event, but its exact mechanism is still full of mystery. In 2009, Higashiyama and his colleagues discovered that a synergid cell, which is located next to the egg cell, produces molecules called LUREs that attract pollen tubes in Torenia plants. They also discovered similar LURE peptides in Arabidopsis thaliana in 2012. "We found that the structure of LURE differs according to the plant species, and that LURE of a specific plant attracts pollen tubes of the same species, which preserves fertilization between the same species," describes Higashiyama. "Therefore, LURE has been identified as the key factor produced by the female organ to attract the male organ in plants." Nevertheless, the mechanism on how pollen tubes can detect LURE, how the pollen tubes grow to a position inside the pistil where they can detect LURE, and the factors behind growth and responses of the pollen tubes have been unknown. Higashiyama's team decided to look into these questions by trying to unveil the key factors in pollen tubes that enable it to detect LURE. "By using Arabidopsis thaliana as a model, we hypothesized that the 23 kinase receptors specifically localized on the membrane surface of pollen tubes could be candidates that are necessary to detect LURE," says Takeuchi. "I conducted bioassays of pollen tubes by deactivating the function of each kinase receptor and found that the PRK6 receptor was essential to detect LURE." For PRK6, there are actually multiple families of receptors that have a similar amino acid sequence. Upon deactivating the function of other PRK receptors, Takeuchi and Higashiyama found that the loss of various combinations of PRK receptors led to reductions in responses of the pollen tubes to LURE or hindered pollen tube growth. This coincides with previous reports that the growth of pollen tubes is induced by the PRK receptor responding to the signals sent from the pistil. Hence, the team found that PRK6 and its other PRK receptors work together to detect LURE as well as enable pollen tubes to grow to a position inside a pistil where it can detect LURE. Takeuchi next studied how PRK6 sends signals within the cells of the pollen tube to understand how it responds to LURE. "When the pollen tube is growing in a straight direction, PRK6 is distributed equally across the cell membrane," explains Takeuchi. "I used fluorescently labeled PRK6 and upon addition of LURE to the pollen tube, I observed that PRK6 moves towards the area of cell membrane on the tip of the pollen tube that faces LURE. The pollen tube then changes its direction and starts to grow towards LURE." From these results, the team showed that PRK6 collects the factors necessary for pollen tube growth in the direction of LURE. "Although the attraction of pollen tubes is considered to occur preferentially between the same species, we wanted to see whether if we can make it occur between different species," says Higashiyama. Upon treatment of LURE from Arabidopsis thaliana to a pollen tube of a Capsella rubella (pink shepherd's-purse) plant, which is in the same Brassicaceae (Cruciferae) family as Arabidopsis thaliana, no response to LURE was observed. "Interestingly, when we inserted the PRK6 gene of Arabidopsis thaliana into the pollen tube of Capsella rubella, it responded to the LURE of Arabidopsis thaliana," says Takeuchi. "This data shows that the PRK6 receptor in the pollen tube is surely the key factor to detect LURE of the same species. We were also really excited to see pollen tube attraction occur between a pollen tube and a LURE of a different species," say Takeuchi and Higashiyama. The generation of seeds through the fertilization of the pistil by the stamen has been known for over 2000 years ago and is an extremely important mechanism in agriculture. In addition, the fact that pollen tubes are attracted to the pistil organ has been discovered over 100 years ago. Since the discovery of the attractant molecule LURE, the disclosure of the mechanism of response to the protein has been sought. This study reveals that the PRK6 receptor in pollen tubes is the main factor for detection of and growth towards LURE. "By further investigation on the family of PRK receptors, we hope to unveil the full mechanism of fertilization that occurs through the growth of pollen tubes and the detection of LURE," say Takeuchi and Higashiyama. "We also found in our studies that the insertion of a PRK6 receptor gene allows attraction of the pollen tube of a different species," says Higashiyama. "This may have potential in developing new methods to enable fertilization between different species. By exploring molecules that target PRK receptors, this may lead to the production of agrochemicals that can improve seed production by increasing the fertilization rate. We also envisage that this study will trigger new research to enable fertilization between different species to create new and useful plant species that can contribute towards a sustainable food supply," he continues. More information: Hidenori Takeuchi et al. Tip-localized receptors control pollen tube growth and LURE sensing in Arabidopsis, Nature (2016). DOI: 10.1038/nature17413


Mazza T.,Mendel Institute | Ballarini P.,École Centrale Paris | Guido R.,University of Calabria | Prandi D.,Center for Integrative Biology
IEEE/ACM Transactions on Computational Biology and Bioinformatics | Year: 2012

Important achievements in traditional biology have deepened the knowledge about living systems leading to an extensive identification of parts-list of the cell as well as of the interactions among biochemical species responsible for cell's regulation. Such an expanding knowledge also introduces new issues. For example, the increasing comprehension of the interdependencies between pathways (pathways cross-talk) has resulted, on one hand, in the growth of informational complexity, on the other, in a strong lack of information coherence. The overall grand challenge remains unchanged: to be able to assemble the knowledge of every "piece of a system in order to figure out the behavior of the whole (integrative approach). In light of these considerations, high performance computing plays a fundamental role in the context of in-silico biology. Stochastic simulation is a renowned analysis tool, which, although widely used, is subject to stringent computational requirements, in particular when dealing with heterogeneous and high dimensional systems. Here, we introduce and discuss a methodology aimed at alleviating the burden of simulating complex biological networks. Such a method, which springs from graph theory, is based on the principle of fragmenting the computational space of a simulation trace and delegating the computation of fragments to a number of parallel processes. © 2012 IEEE.


News Article | November 29, 2016
Site: phys.org

Flowering plants form various organs, such as the flower, leaves, root and stem, which develops along its body axis. As many plants take up a cylinder-like shape, the most important axis becomes the apical-basal (shoot-root) axis, i.e. the apical (top part) develops into shoots, containing flowers, stems and leaves, and the basal (bottom part) grows into roots. The fertilized egg cell (zygote), which is the origin for plants, establishes the plant's body axis from its first cell division. Before cell division occurs, the contents within the zygote become unevenly distributed (polarized). This results in an unequal (asymmetric) cell division, generating a relatively small cell on top and a large cell at the bottom. "Although polarization and asymmetric cell division of zygotes to form the body axis is a common phenomena found in algae, mosses, and flowering plants, the origin of cell polarity and how asymmetric cell division occurs have remained a mystery up to now," says Dr. Minako Ueda, a lecturer at ITbM, Nagoya University and a leader of this research. "The reason why this has been difficult was because there was not an efficient method to visualize the dynamics of cell division using the living zygote hiding deep inside the plants," she continues. In 2015, Dr. Daisuke Kurihara's research group at Nagoya University reported a technique to visualize the growth of living embryos in a model plant, Arabidopsis thaliana (Arabidopsis). Ueda, Kurihara and their colleagues improved the resolution of this imaging technique to be able to observe the internal structure of the cell. "The most difficult part of this research was to be able to identify the suitable markers to visualize the contents of the plant cell," explains Ueda. "With the help of Dr. Tomokazu Kawashima at the University of Kentucky and Professor Frederic Berger at the Mendel Institute, we tried different combinations of colored markers based on green fluorescent proteins (GFPs) to create a contrast between the different components within the cell. Yusuke Kimata, a graduate student in our group, conducted experiments to observe what was actually happening to the egg cell after fertilization." The group succeeded in visualizing for the first time, how the cytoskeleton of plant egg cells is disassembled after fertilization and then reorganized to create a polarity in the cell that eventually leads to asymmetric cell division. Plant cells contain two major cytoskeletons, i.e. microtubules (MTs) and actin filaments (F-actin), which help cells to maintain their shape, provide mechanistic support and enable the cells to divide and move. Ueda and Kimata used fluorescent markers of MTs and F-actin to see how they change before and after fertilization, and how the two fibers play a role in the polarization and asymmetric division of the zygote. "From our live cell imaging experiments, we observed that MTs that were initially aligned along the top-bottom axis of the unfertilized egg cell, disintegrates upon fertilization, leading to shrinkage of the cell," describes Ueda. "After nearly 3 hours, a ring structure appeared at the top part of the zygote, from where a bulge appeared to elongate the cell. This ring structure was retained while the cell elongated. Finally, the MTs gathered around the nucleus after about 18 hours and distributed the chromosomes, eventually leading to cell division after about 22 hours," she continues. "We were really excited when we saw this movie, where the zygotes behave like a stretched Japanese rice cake, as this event was nothing like we have seen before." The group then studied the dynamics of F-actin by live imaging techniques. In a similar manner to MTs, the initial assembly of F-actin in an unfertilized egg cell was disrupted upon fertilization. "What was different for F-actin, was that they align along the top-bottom axis after fertilization, and gather in a cap structure at the tip of the cell," describes Ueda. "We were able to observe that the initial assembly of both MTs and F-actin are disrupted upon fertilization of the egg cell, and the growing zygote gradually aligns these fibers in a different pattern from those in the egg cell. This is the first time to visualize the real time event of asymmetric cell division, and we were able to see other events such as cell elongation of the zygote and migration of the nucleus." Not only did the group succeed in visualizing the real time events of zygote polarization and asymmetric cell division, they were able to quantify the dynamic patterns of the cytoskeleton (i.e. formation of the ring structure and longitudinal array of MTs and F-actin, respectively). Experts of image analysis, Dr. Takumi Higaki and Professor Seiichiro Hasezawa at the University of Tokyo, performed these detailed quantification experiments. The group hypothesized that MTs and F-actin play different roles in the zygote due to their different alignment in the cell. In order to investigate their specific roles, they used inhibitors of each protein to see their effect on zygote polarization and asymmetric cell division. "Through live imaging, we saw that inhibition of MTs hinders zygote elongation, resulting in formation of a round and swollen shape of the zygote head," describes Ueda. "On the other hand, when we inhibited F-actin, the nucleus was unable to move upwards and remained near the center of the zygote. As a result, cell division occurred at the position of the nucleus, leading to nearly symmetric cell division, where the generated cells were similar in size." The group's results show that MTs are responsible for elongation of the zygote along the top-bottom axis, whereas F-actin plays a role in moving the nucleus towards the top part of the zygote, to make it ready for asymmetric cell division. "We were able to show by live cell imaging that polarization of the cell occurs after fertilization of the egg cell, and both MTs and F-actin play a role in inducing asymmetric cell division to form the plant's body axis," says Ueda. "We hope to be able to find the exact origin of what causes polarization and the components that are being distributed in the cell by visualizing more components in the plant zygote. We envisage that this work will lead to discovering how flowering plants have evolved to form their current structure and shape." Explore further: Development of a triarylmethane compound for possible control of plant growth More information: Yusuke Kimata et al, Cytoskeleton dynamics control the first asymmetric cell division inzygote, Proceedings of the National Academy of Sciences (2016). DOI: 10.1073/pnas.1613979113


PubMed | Mendel Institute and University of Siena
Type: Case Reports | Journal: Journal of Alzheimer's disease : JAD | Year: 2015

Oculodentodigital dysplasia (ODDD) [MIM 164200] is a rare disorder caused by mutations in the gap junction alpha 1 (GJA1) gene encoding for connexin 43 (Cx43). Typical signs include type III syndactyly, microphtalmia, microdontia, and neurological disturbances. We report a 59-year-old man having clinical symptoms and signs suggestive of ODDD, with some rarely reported features, that is the presence of gross calcifications of basal ganglia and cerebellar nuclei. Mutation analysis of GJA1 gene identified an unreported heterozygous missense mutation [NM_000165.3:c.124G>C;p.(Glu42Gln)], which may be thought to alter the brain microvessels leading to massive calcifications, as in primary familial brain calcification.


PubMed | Messina University, Mendel Institute, University of Bologna, University of Ferrara and Bambino Gesu Childrens Hospital
Type: Case Reports | Journal: American journal of medical genetics. Part A | Year: 2016

Temple syndrome (TS) is caused by abnormal expression of genes at the imprinted locus 14q32. A subset of TS patients carry 14q32 deletions of paternal origin. We aimed to define possible genotype-phenotype correlations and to highlight the prevalence of thyroid dysfunction, which is a previously unreported feature of TS. We described four new patients who carry deletions of paternal origin at 14q32 detected by array-CGH and reviewed nine patients reported in the medical literature. We compared clinical features with respect to deletion size and position. Expression of DLK1 is altered in all the patients with TS, but intellectual disability (ID) is present only in patients with larger deletions extending proximally to the imprinted locus. This study led to the identification of an ID critical region containing four annotated genes including YY1 as the strongest candidate. Furthermore, we described three patients with thyroid dysfunction, which progressed to papillary carcinoma at a very young age in two of them. We conclude that DLK1 loss of function is likely to be responsible for the core features of TS, while haploinsufficiency of a gene outside the imprinted region causes ID. Thyroid cancer may be an unrecognized feature and monitoring for thyroid dysfunction should thus be considered in TS patients.


PubMed | Mendel Institute
Type: Case Reports | Journal: American journal of medical genetics. Part A | Year: 2015

Oculo auriculo vertebral spectrum (OAVS; OMIM 164210) is a clinically and genetically heterogeneous disorder originating from an abnormal development of the first and second branchial arches. Main clinical characteristics include defects of the aural, oral, mandibular, and vertebral development. Anomalies of the cardiac, pulmonary, renal, skeletal, and central nervous systems have also been described. We report on a 25-year-old male showing a spectrum of clinical manifestations fitting the OAVS diagnosis: hemifacial microsomia, asymmetric mandibular hypoplasia, preauricular pits and tags, unilateral absence of the auditory meatus, dysgenesis of the inner ear and unilateral microphthalmia. A SNP-array analysis identified a de novo previously unreported microduplication spanning 723 Kb on chromosome 3q29. This rearrangement was proximal to the 3q29 microdeletion/microduplication syndrome region, and encompassed nine genes including ATP13A3 and XXYLT1, which are involved in the organogenesis and regulation of the Notch pathway, respectively. The present observation further expands the spectrum of genomic rearrangements associated to OAVS, underlying the value of array-based studies in patients manifesting OAVS features.

Loading Mendel Institute collaborators
Loading Mendel Institute collaborators