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Chromatin and University of Chicago | Date: 2015-05-29

The present invention provides for the nucleic acid sequences of plant centromeres. This will permit construction of stably inherited recombinant DNA constructs and minichromosomes which can serve as vectors for the construction of transgenic plant and animal cells.

Priming of lineage-specific genes in pluripotent embryonic stem cells facilitates rapid and coordinated activation of transcriptional programmes during differentiation. There is growing evidence that pluripotency factors play key roles in priming tissue-specific genes and in the earliest stages of lineage commitment. As differentiation progresses, pluripotency factors are replaced at some primed genes by related lineage-specific factors that bind to the same sequences and maintain epigenetic priming until the gene is activated. Polycomb and trithorax group proteins bind many genes in pluripotent cells generating bivalent domains that contain both active and repressive histone modifications. The properties of polycomb proteins suggest that they act as gatekeepers, helping to maintain silencing in pluripotent stem cells while establishing a chromatin environment that is permissive for priming by sequence-specific factors. The overall effect of factor-mediated priming is to initiate the input of information required for cell differentiation before the first lineage choices have been made. © 2012 WILEY Periodicals, Inc.

Hajkova P.,Chromatin
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2011

Epigenetic reprogramming in the germline provides a developmental model to study the erasure of epigenetic memory as it occurs naturally in vivo in the course of normal embryonic development. Our data show that germline reprogramming comprises both active DNA demethylation and extensive chromatin remodelling that are mechanistically linked through the activation of the base excision DNA repair pathway involved in the DNA demethylation process. The observed molecular hallmarks of the germline reprogramming exhibit intriguing similarities to other dedifferentiation or regeneration systems, pointing towards the existence of unifying molecular pathways underlying cell fate reversal. Elucidation of molecular processes involved in the resetting of epigenetic informationin vivo will thus add to our ability to manipulate cell fate and to restore pluripotency in in vitro settings. © 2011 The Royal Society.

Volle C.,Chromatin | Dalal Y.,Chromatin
Current Opinion in Genetics and Development | Year: 2014

The eukaryotic genome exists in vivo at an equimolar ratio with histones, thus forming a polymer composed of DNA and histone proteins. Each nucleosomal unit in this polymer provides versatile capabilities and dynamic range. Substitutions of the individual components of the histone core with structurally distinct histone variants and covalent modifications alter the local fabric of the chromatin fiber, resulting in epigenetic changes that can be regulated by the cell. In this review, we highlight recent advances in the study of histone variant structure, assembly, and inheritance, their influence on nucleosome positioning, and their cumulative effect upon gene expression, DNA repair and the progression of disease. We also highlight fundamental questions that remain unanswered regarding the behavior of histone variants and their influence on cellular function in the normal and diseased states. © 2013.

Gambetta M.C.,Chromatin | Muller J.,Chromatin
Developmental Cell | Year: 2014

The glycosyltransferase Ogt adds O-linked N-Acetylglucosamine (O-GlcNAc) moieties to nuclear and cytosolic proteins. Drosophila embryos lacking Ogt protein arrest development with a remarkably specific Polycomb phenotype, arising from the failure to repress Polycomb target genes. The Polycomb protein Polyhomeotic (Ph), an Ogt substrate, forms large aggregates in the absence of O-GlcNAcylation both invivo and invitro. O-GlcNAcylation of a serine/threonine (S/T) stretch in Ph is critical to prevent nonproductive aggregation of both Drosophila and human Ph via their C-terminal sterile alpha motif(SAM) domains invitro. Full Ph repressor activity invivo requires both the SAM domain and O-GlcNAcylation of the S/T stretch. We demonstrate that Ph mutants lacking the S/T stretch reproduce the phenotype of ogt mutants, suggesting that theS/T stretch in Ph is the key Ogt substrate in Drosophila. We propose that O-GlcNAcylation is needed for Ph to form functional, ordered assemblies via its SAM domain. © 2014 Elsevier Inc.

Hajkova P.,Chromatin
Current Opinion in Cell Biology | Year: 2010

Epigenetic reprogramming involves processes that lead to the erasure of epigenetic information. Such instances are typically connected with the reversal of differentiation and can potentially lead to the re-establishment of the pluripotent (embryonic stem (ES)-like) phenotype. Genome-wide epigenetic reprogramming occurs naturally in vivo in the course of normal mammalian development. Although in vitro reprogramming systems that can restore pluripotency in somatic cell have been designed, they are still very inefficient and the process requires considerably more time than the reprogramming processes that occur in vivo. Careful analysis of the developmental reprogramming events can give us mechanistic clues and enable us to design better in vitro experimental strategies. © 2010 Elsevier Ltd.

Ballestar E.,Chromatin
Nature Reviews Rheumatology | Year: 2011

The potential roles of epigenetic alterations in the pathogenesis of autoimmune rheumatic diseases are raising great expectations among clinicians and researchers. Epigenetic mechanisms regulate gene expression and are sensitive to external stimuli, bridging the gap between environmental and genetic factors. Considerable evidence of epigenetic changes, particularly altered patterns of DNA methylation, exists in diseases such as systemic lupus erythematosus (SLE) and rheumatoid arthritis. The importance of such changes in the pathology of rheumatic diseases has been demonstrated by examining the relationship between gene-specific methylation and SLE in monozygotic twins discordant for the disease, in whom genetic variability is excluded as a cause for discordance. Several studies have highlighted the importance of the tissue-specificity of DNA methylation changes, an aspect whichĝ€ "in contrast with genetic analysisĝ€"must be considered when designing epigenetic studies. Here I discuss the proposed mechanisms and implications of DNA methylation changes in the pathogenesis of autoimmune rheumatic diseases, the prospects for future epigenetic studies in rheumatology, the relevance of specific DNA methylation markers and the potential use of drugs with an epigenetic effect in the clinical management of these diseases. © 2011 Macmillan Publishers Limited. All rights reserved.

RNAi vectors comprising a fragment of the SbCSE polynucleotide sequence and transgenic plants, e.g. transgenic sorghum plants, comprising said RNAi vectors are described. Aspects of the technology are further directed to methods of using the RNAi vectors of the present technology to silence SbCSE gene expression or activity in a transgenic plant, such as a transgenic sorghum plant. Silencing the SbCSE gene leads to reduced lignin content in a transgenic plant.

Chromatin | Date: 2015-08-03

The invention is generally related to MCs containing sorghum centromere sequences. In addition, the invention provides for methods of generating plants transformed with these MCs. MCs with novel compositions and structures are used to transform plants cells which are in turn used to generate the plant. Methods for generating the plant include methods for delivering the MC into plant cell to transform the cell, methods for selecting the transformed cell, and methods for isolating plants transformed with the MC.

Chromatin | Date: 2015-03-17

The invention is generally related to Sugarcane mini-chromosomes and recombinant chromosomes containing Sugarcane centromere sequences. In addition, the invention provides for methods of generating Sugarcane plants transformed with these Sugarcane mini-chromosomes. Sugarcane mini-chromosomes with novel compositions and structures are used to transform Sugarcane cells which are in turn used to generate Sugarcane plants. Methods for generating Sugarcane plants include methods for delivering the Sugarcane mini-chromosomes into Sugarcane cell to transform the cell, methods for selecting the transformed cell, and methods for isolating Sugarcane plants transformed with the Sugarcane mini-chromosome or recombinant chromosome.

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