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Ericson M.,Yale University | Janes M.A.,Yale University | Janes M.A.,San Francisco General Hospital | Butter F.,Max Planck Institute of Biochemistry | And 4 more authors.
BMC Biology

Background: Although technical advances in genomics and proteomics research have yielded a better understanding of the coding capacity of a genome, one major challenge remaining is the identification of all expressed proteins, especially those less than 100 amino acids in length. Such information can be particularly relevant to human pathogens, such as Trypanosoma brucei, the causative agent of African trypanosomiasis, since it will provide further insight into the parasite biology and life cycle.Results: Starting with 993 T. brucei transcripts, previously shown by RNA-Sequencing not to coincide with annotated coding sequences (CDS), homology searches revealed that 173 predicted short open reading frames in these transcripts are conserved across kinetoplastids with 13 also conserved in representative eukaryotes. Mining mass spectrometry data sets revealed 42 transcripts encoding at least one matching peptide. RNAi-induced down-regulation of these 42 transcripts revealed seven to be essential in insect-form trypanosomes with two also required for the bloodstream life cycle stage. To validate the specificity of the RNAi results, each lethal phenotype was rescued by co-expressing an RNAi-resistant construct of each corresponding CDS. These previously non-annotated essential small proteins localized to a variety of cell compartments, including the cell surface, mitochondria, nucleus and cytoplasm, inferring the diverse biological roles they are likely to play in T. brucei. We also provide evidence that one of these small proteins is required for replicating the kinetoplast (mitochondrial) DNA.Conclusions: Our studies highlight the presence and significance of small proteins in a protist and expose potential new targets to block the survival of trypanosomes in the insect vector and/or the mammalian host. © 2014 Ericson et al.; licensee BioMed Central Ltd. Source

Chen C.-J.,University Pierre and Marie Curie | Chen C.-J.,French National Center for Scientific Research | Chen C.-J.,French Institute of Health and Medical Research | Chen C.-J.,MINES ParisTech | And 24 more authors.

Non-coding RNA (ncRNA) PROfiling in small RNA (sRNA)-seq (ncPRO-seq) is a stand-alone, comprehensive and flexible ncRNA analysis pipeline. It can interrogate and perform detailed profiling analysis on sRNAs derived from annotated non-coding regions in miRBase, Rfam and RepeatMasker, as well as specific regions defined by users. The ncPRO-seq pipeline performs both gene-based and family-based analyses of sRNAs. It also has a module to identify regions significantly enriched with short reads, which cannot be classified under known ncRNA families, thus enabling the discovery of previously unknown ncRNA-or small interfering RNA (siRNA)-producing regions. The ncPRO-seq pipeline supports input read sequences in fastq, fasta and color space format, as well as alignment results in BAM format, meaning that sRNA raw data from the three current major platforms (Roche-454, Illumina-Solexa and Life technologies-SOLiD) can be analyzed with this pipeline. The ncPRO-seq pipeline can be used to analyze read and alignment data, based on any sequenced genome, including mammals and plants. © The Author 2012. Published by Oxford University Press. All rights reserved. Source

Ammerpohl O.,University of Kiel | Bens S.,University of Kiel | Appari M.,University of Kiel | Werner R.,University of Lubeck | And 11 more authors.

Sex differences are well known to be determinants of development, health and disease. Epigenetic mechanisms are also known to differ between men and women through X-inactivation in females. We hypothesized that epigenetic sex differences may also result from sex hormone functions, in particular from long-lasting androgen programming. We aimed at investigating whether inactivation of the androgen receptor, the key regulator of normal male sex development, is associated with differences of the patterns of DNA methylation marks in genital tissues. To this end, we performed large scale array-based analysis of gene methylation profiles on genomic DNA from labioscrotal skin fibroblasts of 8 males and 26 individuals with androgen insensitivity syndrome (AIS) due to inactivating androgen receptor gene mutations. By this approach we identified differential methylation of 167 CpG loci representing 162 unique human genes. These were significantly enriched for androgen target genes and low CpG content promoter genes. Additional 75 genes showed a significant increase of heterogeneity of methylation in AIS compared to a high homogeneity in normal male controls. Our data show that normal and aberrant androgen receptor function is associated with distinct patterns of DNA-methylation marks in genital tissues. These findings support the concept that transcription factor binding to the DNA has an impact on the shape of the DNA methylome. These data which derived from a rare human model suggest that androgen programming of methylation marks contributes to sexual dimorphism in the human which might have considerable impact on the manifestation of sex-associated phenotypes and diseases. © 2013 Ammerpohl et al. Source

Persch N.,Saarland University | Elhayek A.,Max Planck Institute for Computer Science | Welk M.,University of Medical Sciences and Technology | Bruhn A.,University of Stuttgart | And 4 more authors.
Measurement Science and Technology

This paper proposes an advanced image enhancement method that is specifically tailored towards 3-D confocal and STED microscopy imagery. Our approach unifies image denoising, deblurring and interpolation in one joint method to handle the typical weaknesses of these advanced microscopy techniques: out-of-focus blur, Poisson noise and low axial resolution. In detail, we propose the combination of (i) Richardson-Lucy deconvolution, (ii) image restoration and (iii) anisotropic inpainting in one single scheme. To this end, we develop a novel PDE-based model that realizes these three ideas. First we consider a basic variational image restoration functional that is turned into a joint interpolation scheme by extending the regularization domain. Next, we integrate the variational representation of Richardson-Lucy deconvolution into our model, and illustrate its relation to Poisson distributed noise. In the following step, we supplement the components of our model with sub-quadratic penalization strategies that increase the robustness of the overall method. Finally, we consider the associated minimality conditions, where we exchange the occurring scalar-valued diffusivity function by a so-called diffusion tensor. This leads to an anisotropic regularization that is aligned with structures in the evolving image. As a further contribution of this paper, we propose a more efficient and faster semi-implicit iteration scheme that also increases the stability. Our experiments on real data sets demonstrate that this joint model achieves a superior reconstruction quality of the recorded cell. © 2013 IOP Publishing Ltd. Source

Soshnikova N.,Institute of Molecular Biology gGmbH
Developmental Dynamics

Hox genes encode transcription factors defining cellular identities along the major and secondary body axes. Their coordinated expression in both space and time is critical for embryonic patterning. Accordingly, Hox genes transcription is tightly controlled at multiple levels, and involves an intricate combination of local and long-range cis-regulatory elements. Recent studies revealed that in addition to transcription factors, dynamic patterns of histone marks and higher-order chromatin structure are important determinants of Hox gene regulation. Furthermore, the emerging picture suggests an involvement of various species of non-coding RNA in targeting activating and repressive complexes to Hox clusters. I review these recent developments and discuss their relevance to the control of Hox gene expression in vivo, as well as to our understanding of transcriptional regulatory mechanisms. © 2013 Wiley Periodicals, Inc. Source

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