Project description:Current approaches to profiling tissue-specific gene expression in C. elegans require delicate manipulation and are difficult under certain conditions, e.g. from dauer or aging worms. We have developed an easy and robust method for tissue-specific RNA-seq by taking advantage of the endogenous trans-splicing process. In this method, transgenic worms are generated in which a spliced leader (SL) RNA gene is fused with a sequence tag and driven by a tissue-specific promoter. Only in the tissue of interest, the tagged SL RNA gene is transcribed and then trans-spliced onto mRNAs. The tag allows enrichment and sequencing of mRNAs from that tissue only. As a proof of principle, we profiled the muscle transcriptome, which showed high coverage and efficient enrichment of muscle specific genes, with low background noise. To demonstrate the robustness of our method, we profiled muscle gene expression in dauer larvae and aging worms, revealing gene expression changes consistent with the physiology of these stages. The resulting muscle transcriptome also revealed 461 novel RNA transcripts, likely muscle-expressed long non-coding RNAs. In summary, the splicing-based RNA tagging (SRT) method provides a convenient and robust tool to profile trans-spliced genes and identify novel transcripts in a tissue-specific manner, with a low false positive rate.
Project description:The conserved ubiquitin-like protein Hub1/UBL-5 associates with proteins non-covalently. In yeast and human cells, Hub1 promotes splicing of precursor mRNAs with weak introns and alternative splicing, however, its splicing function has remained elusive in multicellular organisms. We demonstrate the splicing function of Hub1/UBL-5 in the free-living nematode Caenorhabditis elegans. UBL-5 binds to the HIND-containing splicing factors Snu66/SART-1 and PRP-38 and associates with other spliceosomal proteins. Caenorhabditis elegans hub1/ubl-5 mutants die at the larval L3 stage, and show accumulation of intron- and outron-containing transcripts. The latter observation adds to UBL-5’s splicing function in trans-RNA splicing. UBL-5 complements splicing defects of hub1-knockout Schizosaccharomyces pombe, confirming its functional conservation. Thus, UBL-5 is important for C. elegans development and cis- and trans-RNA splicing.
Project description:Caenorhabditis elegans and its relatives are unique among animals, possibly even among eukaryotes, in having operons. In these regulated multigene transcription units, a polycistronic pre-mRNA is processed to monocistronic mRNAs by 3' end formation and trans-splicing utilizing a special snRNP, the SL2 snRNP, for downstream mRNAs1. Previously, the correlation between downstream location in an operon and SL2 trans-splicing has been strong, but anecdotal. Although only 28 operons have been reported previously, the complete sequence of the genome reveals numerous gene clusters. To determine how many represent operons, we probed full-genome microarrays for SL2-containing mRNAs. We found significant enrichment for about 1200 genes including most of a group of several hundred genes represented by cDNAs that contain SL2 sequence. Analysis of their genomic arrangements indicates that >90% are downstream genes, falling in 790 distinct operons. We conclude that the genome contains at least 1000 operons, 2- 8 genes in length, that contain ~15% of C. elegans genes. Most of the operons have not been reported previously, and numerous examples of co-transcription of genes encoding functionally related proteins are evident. Inspection of the operon list should reveal heretofore unknown functional relationships. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Keywords: Logical Set Computed
Project description:Caenorhabditis elegans and its relatives are unique among animals, possibly even among eukaryotes, in having operons. In these regulated multigene transcription units, a polycistronic pre-mRNA is processed to monocistronic mRNAs by 3' end formation and trans-splicing utilizing a special snRNP, the SL2 snRNP, for downstream mRNAs1. Previously, the correlation between downstream location in an operon and SL2 trans-splicing has been strong, but anecdotal. Although only 28 operons have been reported previously, the complete sequence of the genome reveals numerous gene clusters. To determine how many represent operons, we probed full-genome microarrays for SL2-containing mRNAs. We found significant enrichment for about 1200 genes including most of a group of several hundred genes represented by cDNAs that contain SL2 sequence. Analysis of their genomic arrangements indicates that >90% are downstream genes, falling in 790 distinct operons. We conclude that the genome contains at least 1000 operons, 2- 8 genes in length, that contain ~15% of C. elegans genes. Most of the operons have not been reported previously, and numerous examples of co-transcription of genes encoding functionally related proteins are evident. Inspection of the operon list should reveal heretofore unknown functional relationships. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Keywords: Logical Set
Project description:The Cell Division Cycle and Apoptosis Regulator (CCAR) protein family members have recently emerged as regulators of alternative splicing and transcription, as well as having other key physiological functions. For example, mammalian CCAR2/DBC1 forms a complex with the zinc factor protein ZNF326 to integrate alternative splicing with RNA polymerase II transcriptional elongation in AT-rich regions of the DNA. Additionally, Caenorhabditis elegans CCAR-1, a homolog to mammalian CCAR2, facilitates the alternative splicing of the perlecan unc-52 gene. However, much about the CCAR family's role in alternative splicing is unknown. We are interested in uncovering the role of the CCAR family in alternative splicing in vivo using Caenorhabditis elegans. We examined the role of CCAR-1 in genome-wide alternative splicing and identified new alternative splicing targets of CCAR-1 using RNA sequencing. Also, we found that CCAR-1 interacts with the spliceosome factors UAF-1 and UAF-2 using mass spectrometry, and that knockdown of ccar-1 affects alternative splicing patterns, motility, and proteostasis of UAF-1 mutant worms. Collectively, we demonstrate a role for CCAR-1 in the regulation of global alternative splicing in C. elegans and in conjunction with UAF-1
Project description:Background: The force generating mechanism of muscle is evolutionarily ancient; the fundamental structural and functional components of the sarcomere are common to motile animals throughout phylogeny. Recent evidence suggests that the transcription factors that regulate muscle development are also conserved. Thus, a comprehensive description of muscle gene expression in a simple model organism should define a basic muscle transcriptome that is also expressed in animals with more complex body plans. To this end, we have applied Micro-Array Profiling of Caenorhabditis elegans Cells (MAPCeL) to muscle cell populations extracted from developing Caenorhabditis elegans embryos. Results: Fluorescence Activated Cell Sorting (FACS) was used to isolate myo-3::GFP-positive muscle cells, and their cultured derivatives, from dissociated early Caenorhabditis elegans embryos. Microarray analysis identified 6,693 expressed genes, 1,305 of which are enriched in the myo-3::GFP positive cell population relative to the average embryonic cell. The muscle-enriched gene set was validated by comparisons to known muscle markers, independently derived expression data, and GFP reporters in transgenic strains. These results confirm the utility of MAPCeL for cell type-specific expression profiling and reveal that 60% of these transcripts have human homologs. Conclusions: This study provides a comprehensive description of gene expression in developing Caenorhabditis elegans embryonic muscle cells. The finding that over half of these muscle-enriched transcripts encode proteins with human homologs suggests that mutant analysis of these genes in Caenorhabditis elegans could reveal evolutionarily conserved models of muscle gene function with ready application to human muscle pathologies. Keywords: embryonic muscle, myo-3::GFP