Project description:Suppressing spurious cryptic transcription by a repressive intragenic chromatin state featuring trimethylated lysine 36 on histone H3 (H3K36me3) and DNA methylation is critical for maintaining self-renewal capacity in mouse embryonic stem cells. In yeast and nematodes, such cryptic transcription is elevated with age, and reducing the levels of age-associated cryptic transcription extends yeast lifespan. Whether cryptic transcription is also increased during mammalian aging is unknown. We show for the first time an age-associated elevation in cryptic transcription in several stem cell populations, including murine hematopoietic stem cells (mHSCs) and neuronal stem cells (NSCs) and human mesenchymal stem cells (hMSCs). Using DECAP-seq, we mapped and quantified age-associated cryptic transcription in hMSCs aged in vitro. Regions with significant age-associated cryptic transcription have a unique chromatin signature: decreased H3K36me3 and increased H3K4me1, H3K4me3, and H3K27ac with age. Furthermore, genomic regions undergoing such age-dependent chromatin changes resemble known promoter sequences and are bound by the promoter-associated protein TBP even in young cells. Hence, the more permissive chromatin state at intragenic cryptic promoters likely underlies the increase of cryptic transcription in aged mammalian stem cells.
Project description:Transcriptional profiling of larval epidermis at specific markings were examined using 11 developmental stages. Gene expression level was compared between mimetic white, cryptic thorax, and cryptic abdomen vs. mimetic black, cryptic eyespot, and cryptic V-shaped markings in all stages. For initial screening of marking-specific genes, 6 developmental stages for mimetic pattern, and 5 developmental stages for cryptic pattern was used. Mimetic white, cryptic thorax, and cryptic abdomen were independently labelled with Cyanine 3-CTP (Cy3), and mimetic black, cryptic eyespot, and cryptic V-shaped markings were independently labelled with Cyanine 5-CTP (Cy5) in all stages.
Project description:It has previously been shown that Isw2 represses cryptic antisense transcripts from the 3’-end of three genes. However, whether Isw2 generally functions to repress cryptic RNA transcription is currently unknown. We thus sought to determine the loci at which Isw2 is required to repress cryptic non-coding RNA (ncRNA) expression and to map their transcription start sites relative to nucleosome positions on a global scale.
2010-07-31 | GSE23108 | GEO
Project description:Bacteriome of Universidad Nacional de Villa María
Project description:To identify chromatin alterations in primary gastric adenocarcionomas, we performed nano-scale chromatin immunoprecipitation-sequencing (Nano-CHiPseq) of histone modifications in 5 gastric cancers and matched normal tissues, We identified hundreds of somatically-altered promoters (marked by H3K4me3) and enhancers (H3K4me1). The majority of cancer-associated promoters localized to genomic sites lacking previously-annotated transcription start sites (“cryptic promoters”), driving high expression of nearby genes implicated in gastrointestinal cancers, embryonic development, and tissue specification. Our findings demonstrate the feasibility of performing chromatin profiling on solid tumors where tissue is limiting, to identify in non-coding regions regulatory elements, transcriptional patterns and genetic variants associated with cancer. We propose a pervasive role for cryptic promoters in the reactivation of early developmental programs in gastric cancer, and the potential utility of cryptic promoters as biomarkers of malignancy. Five gastric cancer tumor normal pairs are profiling in multiple number of chromatin marks