Project description:By screening for genes possessing canonical X-box sequences in promoters of three Caenorhabditis species, namely C. elegans, C. briggsae and C. remanei, we identified 93 genes (including known X-box regulated genes) that encode putative components of ciliated neurons in C. elegans and are subject to the same regulatory control. For many of these genes, restricted anatomical expression in ciliated cells was confirmed, and control of transcription by the ciliogenic DAF-19 RFX transcription factor was demonstrated by comparative transcriptional profiling of daf-19(+) and daf-19(-) animals. Experiment Overall Design: There 4 samples.
Project description:By screening for genes possessing canonical X-box sequences in promoters of three Caenorhabditis species, namely C. elegans, C. briggsae and C. remanei, we identified 93 genes (including known X-box regulated genes) that encode putative components of ciliated neurons in C. elegans and are subject to the same regulatory control. For many of these genes, restricted anatomical expression in ciliated cells was confirmed, and control of transcription by the ciliogenic DAF-19 RFX transcription factor was demonstrated by comparative transcriptional profiling of daf-19(+) and daf-19(-) animals. Keywords: Microarry analysis; DAF-19; X-box motif; C. elegans; transcription; comparative genomics
Project description:Cilia are ubiquitous cell surface projections that modulate various sensory- and motility based processes and are implicated in a growing number of multi-organ genetic disorders termed ciliopathies. As new components required for cilium biogenesis and function remain unidentified, we sought to further define and validate the transcriptional targets of the ciliogenic C. elegans RFX transcription factor DAF-19. To this end, transcriptional profiling of daf-19 mutants (which do not form cilia) and wild-type animals was performed using selectively staged embryos where ciliogenesis occurs in most ciliated sensory neurons (CSNs). Statistical comparisons between the two populations revealed 881 differentially regulated genes with 1.5-fold change or greater. A subset of these was confirmed by quantitative RT-PCR. Transgenic worms expressing transcriptional-GFP fusions revealed CSN-specific expression patterns for 9 of 12 candidate genes. We show that two uncharacterized candidate genes, which we term dyf-17 and dyf-18 because their corresponding mutants display dye-filling (Dyf) defects, are important for ciliogenesis. DYF-17 localizes at the base of cilia and interestingly, is specifically required for building the distal segment of sensory cilia. DYF-18 is an evolutionarily conserved CDK-7/CCRK-related serine-threonine kinase that is necessary for the proper function of intraflagellar transport (IFT), a process critical for cilium biogenesis. Together, our comparative microarray study identifies targets of the evolutionarily conserved RFX transcription factor, DAF-19, providing a rich dataset from which to uncover—in addition to DYF-17 and DYF-18—cellular components important for cilium formation and function. 4 daf-19,daf12; 4 daf-12; 4 WT
Project description:Cilia are ubiquitous cell surface projections that modulate various sensory- and motility based processes and are implicated in a growing number of multi-organ genetic disorders termed ciliopathies. As new components required for cilium biogenesis and function remain unidentified, we sought to further define and validate the transcriptional targets of the ciliogenic C. elegans RFX transcription factor DAF-19. To this end, transcriptional profiling of daf-19 mutants (which do not form cilia) and wild-type animals was performed using selectively staged embryos where ciliogenesis occurs in most ciliated sensory neurons (CSNs). Statistical comparisons between the two populations revealed 881 differentially regulated genes with 1.5-fold change or greater. A subset of these was confirmed by quantitative RT-PCR. Transgenic worms expressing transcriptional-GFP fusions revealed CSN-specific expression patterns for 9 of 12 candidate genes. We show that two uncharacterized candidate genes, which we term dyf-17 and dyf-18 because their corresponding mutants display dye-filling (Dyf) defects, are important for ciliogenesis. DYF-17 localizes at the base of cilia and interestingly, is specifically required for building the distal segment of sensory cilia. DYF-18 is an evolutionarily conserved CDK-7/CCRK-related serine-threonine kinase that is necessary for the proper function of intraflagellar transport (IFT), a process critical for cilium biogenesis. Together, our comparative microarray study identifies targets of the evolutionarily conserved RFX transcription factor, DAF-19, providing a rich dataset from which to uncover—in addition to DYF-17 and DYF-18—cellular components important for cilium formation and function.
Project description:Cilia are required for many sensory and motility related functions and are involved in growing number of genetic disorders termed ciliopathies. DAF-19, RFX type transcription factor controls expression of many cilia structure and function related genes. To this end, transcriptional profiling of daf-19 mutants (which do not form cilia) and wild-type animals was performed using selectively staged larval stages where cilia mature and maintained, structurally as well as functionally.
Project description:We have performed a systems-level analysis of the RFX/Daf-19 family transcription factor, Rfx2. Using a combination of high-throughput sequencing of Rfx2-regulated transcripts and chromosomal binding sites, we provide a comprehensive accounting of the target genes by which Rfx2 controls ciliogenesis and cilia beating in vertebrates.
Project description:Many tissue-specific stem cells maintain the ability to produce multiple cell types during long periods of non-division, or quiescence. FOXO transcription factors promote quiescence and stem cell maintenance, but the mechanisms by which FOXO proteins promote multipotency during quiescence are still emerging. The single FOXO ortholog in C. elegans, daf-16, promotes entry into a quiescent and stress-resistant larval stage called dauer in response to adverse environmental cues. During dauer, stem and progenitor cells maintain or re-establish multipotency to allow normal development to resume after dauer. We find that during dauer, daf-16/FOXO prevents epidermal stem cells (seam cells) from prematurely adopting differentiated, adult characteristics. In particular, dauer larvae that lack daf-16 misexpress collagens that are normally adult-enriched. Using col-19p::gfp as an adult cell fate marker, we find that all major daf-16 isoforms contribute to opposing col-19p::gfp expression during dauer. By contrast, daf-16(0) larvae that undergo non-dauer development do not misexpress col-19p::gfp. Adult cell fate and the timing of col-19p::gfp expression are regulated by the heterochronic gene network, including lin-41 and lin-29. lin-41 encodes an RNA-binding protein orthologous to LIN41/TRIM71 in mammals, and lin-29 encodes a conserved zinc finger transcription factor. In non-dauer development lin-41 opposes adult cell fate by inhibiting the translation of lin-29, which directly activates col-19 transcription and promotes adult cell fate. We find that during dauer, lin-41 blocks col-19p::gfp expression, but surprisingly, lin-29 is not required in this context. Additionally, daf-16 promotes the expression of lin-41 in dauer larvae. The col-19p::gfp misexpression phenotype observed in dauer larvae with reduced daf-16 requires the downregulation of lin-41, but does not require lin-29. Taken together, this work demonstrates a novel role for daf-16/FOXO as a heterochronic gene that promotes expression of lin-41/TRIM71 to contribute to multipotent cell fate in a quiescent stem cell model.