Project description:Recent work has shown that small non-coding RNAs, including miRNAs, serve an important role in controlling gene expression during development and disease. However, little detailed information exists concerning the relative expression patterns of small RNAs during development of C. elegans. Here we use recent advances in high-throughput sequencing technology to show that expression of non-coding small RNAs, including miRNAs, changes dynamically during development and in the different sexes of C. elegans; approximately 16% of known miRNAs changed over 10 fold in expression during C. elegans development and about 12% of miRNAs showed major changes in expression between males and hermaphrodites of C. elegans. These results should lead to a better understanding of the expression and function of small RNAs in C. elegans development. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf
Project description:The nematode Caenorhabditis elegans (C. elegans) is often used as a model organism to study cell and developmental biology. Quantitative mass spectrometry has only recently been performed in C. elegans and, so far, most studies have been done on adult worm samples. Here we use quantitative mass spectrometry to characterise protein level changes across the four larval developmental stages (L1-L4) of C. elegans, in biological triplicate. In total, we identify 4,130 proteins and quantify 1,541 proteins that were identified across all four stages in all three biological repeats with at least 2 unique peptides per protein. Using hierarchical clustering and functional ontological analyses, we identify 21 protein groups containing proteins with similar protein profiles across the four stages, and highlight the most overrepresented biological functions in each of these protein clusters. In addition, we use the dataset to identify putative larval stage specific proteins in each individual developmental stage, as well as in the early and late developmental stages. In summary, this dataset provides a system-wide analysis of protein level changes across the four C. elegans larval developmental stages, which serves as a useful resource for the worm development research community.
Project description:Recent work has shown that small non-coding RNAs, including miRNAs, serve an important role in controlling gene expression during development and disease. However, little detailed information exists concerning the relative expression patterns of small RNAs during development of C. elegans. Here we use recent advances in high-throughput sequencing technology to show that expression of non-coding small RNAs, including miRNAs, changes dynamically during development and in the different sexes of C. elegans; approximately 16% of known miRNAs changed over 10 fold in expression during C. elegans development and about 12% of miRNAs showed major changes in expression between males and hermaphrodites of C. elegans. These results should lead to a better understanding of the expression and function of small RNAs in C. elegans development. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf Examination of small RNA expression in six different developmental stages of hermaphrodites (Embryo, mid-L1, mid-L2, mid-L3, mid-L4, young adult), and young adult males (dpy-28;him-8) and spermatogenesis-defective young adult hermaphrodites (spe-9). The number of sequence reads for miRNA was assessed from the raw sequence data from Solexa sequencing using perfect sequence matching to known miRNAs (miRBase Release 11.0).
Project description:Despite highly conserved chromatin states and cis-regulatory elements, studies of metazoan genomes reveal that gene organization and the strategies to control mRNA expression can vary widely among animal species. C. elegans gene regulation is often assumed to be similar to that of other model organisms, yet evidence suggests the existence of distinct molecular mechanisms to pattern the developmental transcriptome, including extensive post-transcriptional RNA control pathways, widespread splice leader (SL) trans-splicing of pre-mRNAs, and the organization of genes into operons. Here, we performed ChIP-seq for histone modifications in highly synchronized embryos cohorts representing three major developmental stages, with the goal of better characterizing whether the dynamic changes in embryonic mRNA expression are accompanied by changes to the chromatin state. We were surprised to find that thousands of promoters are persistently marked by active histone modifications, despite a fundamental restructuring of the transcriptome. We employed global run-on sequencing using a long-read nanopore format to map nascent RNA transcription across embryogenesis, finding that the invariant open chromatin regions are persistently transcribed by Pol II at all stages of embryo development, even though the mature mRNA is not produced. By annotating our nascent RNA sequencing reads into directional transcription units, we find extensive evidence of polycistronic RNA transcription genome-wide, suggesting that nearby genes in C. elegans are linked by shared transcriptional regulatory mechanisms. We present data indicating that the sharing of cis-regulatory sequences has constrained C. elegans gene positioning and likely explains the remarkable retention of syntenic gene pairs over long evolutionary timescales.
Project description:Here, we profile miRNA expression at high temporal resolution (1 hr interval) during C. elegans postembryonic development, which identifies several miRNAs with highly dynamic concentration changes
Project description:An essential step for understanding the transcriptional circuits that control development and physiology is the global identification and characterization of regulatory elements. Here we present the first map of regulatory elements across the development and ageing of an animal, identifying 42,245 elements accessible in at least one C. elegans stage. Based on nuclear transcription profiles, we define 15,918 protein-coding promoters and 17,918 putative enhancers, and find that both types of element can drive orientation-independent transcription. Additionally, hundreds of promoters produce transcripts antisense to protein coding genes, suggesting involvement in a widespread regulatory mechanism. We find that the accessibility of most elements is regulated during development and/or ageing and that patterns of accessibility change are linked to specific developmental or physiological processes. The map and characterization of regulatory elements across C. elegans life provides a platform for understanding how transcription controls development and ageing.