We report the presence of extensive, transcriptionally controlled oscillations in the C. elegans, developmental transcriptome. Furthermore, using ribosome profiling, we show that these oscillating transcripts are actively translated. Overall design: Examination of three timecourses that were collected over C. elegans development and analyzed by RNA-seq of mRNA libraries
Extensive oscillatory gene expression during C. elegans larval development.
Cell line, Subject
View SamplesWe report the presence of extensive, transcriptionally controlled oscillations in the C. elegans, developmental transcriptome. Furthermore, using ribosome profiling, we show that these oscillating transcripts are actively translated. Overall design: Examination of two timecourses that were collected over C. elegans development and analyzed by RNA-seq of "RiboMinus" libraries
Extensive oscillatory gene expression during C. elegans larval development.
Cell line, Subject
View SamplesXRN2 is a conserved 5’-->3’ exoribonuclease that complexes with XTB-domain containing proteins. Thus, in Caenorhabditis elegans (C. elegans), the XTBD-protein PAXT-1 stabilizes XRN2 to retain its activity. XRN2 activity is also promoted by 3''(2''),5''-bisphosphate nucleotidase 1 (BPNT1) through its hydrolysis of 3’-phosphoadenosine-5''-bisphosphate (PAP), an endogenous XRN inhibitor. Here, we find through unbiased screening that loss of bpnt-1 function suppresses lethality caused by paxt-1 deletion. This unexpected finding is explained by XRN2 autoregulation, which occurs through repression of a cryptic promoter activity and destabilization of the xrn-2 transcript. Autoregulation appears to be triggered at different thresholds of XRN2 inactivation, such that more robust XRN2 perturbation, by elimination of both PAXT-1 and BPNT1, is less detrimental to worm viability than absence of PAXT-1 alone. Like more than 15% of C. elegans genes, xrn-2 occurs in an operon, and we identify additional operons under its control, consistent with a broader function of XRN2 in polycistronic gene regulation. Regulation occurs through intercistronic regions that link genes in an operon, but similar mechanisms may allow XRN2 to operate on monocistronic genes in organisms lacking operons. Overall design: Wild-type C. elegans worms were subjected to mock or xrn-2 RNAi from L1 to L4 stage at 20°C. Total RNA was extracted from the worms, and polyadenylated RNA was analyzed.
XRN2 Autoregulation and Control of Polycistronic Gene Expresssion in Caenorhabditis elegans.
Cell line, Subject
View SamplesmicroRNAs (miRNAs) constitute a class of small non-coding RNAs (~22nt). They are thought to be generally stable with half-lives of many hours or even days. However, several miRNAs have been reported to decay rapidly in specific situations. In order to examine miRNA stability on a global scale, we quantify relative decay rates of miRNA in first larval stage C. elegans worms that are treated with a transcription inhibitor alpha-amanitin by deep sequencing. Several miRNAs including members of the miR-35 and miR-51 families exhibit accelerated decay. Moreover, biogenesis of miRNAs involves generation of a miRNA duplex intermediate consisting of the miRNA guide strand (miR) and the miRNA passenger strand (miR*). miR and miR* names were originally assigned based on the relative abundance of each strand, with the less abundant strand presumed to be inactive, and thus the miR*. However, subsequent research showed that at least individual miR*s can have biological activity. Our sequencing data reveal that miR*s, operationally defined on the basis of their relative abundance at time point t=1h, are substantially less stable than miRs. This would appear to support the notion that miR*s mainly constitute processing byproducts rather than a less abundant class of functional miRNAs. Overall design: Examination of microRNA decay rates in the first larval stage C. elegans worms.
Engineering of a conditional allele reveals multiple roles of XRN2 in Caenorhabditis elegans development and substrate specificity in microRNA turnover.
Specimen part, Cell line, Treatment, Subject
View SamplesWe perform RNA sequencing and ribosome profiling time course experiments to examine the effect of fully dysregulating all let-7 targets (in let-7(n2853) animals), partially dysregulating only LIN41 (in lin-41(xe11) animals) or fully dysregulating all let-7 targets while partially dysregulating LIN41 in lin-41(xe11); let-7(n2853) double mutant animals. We conclude that effects on gene expression in let-7 mutant animals are largely and quantitatively explained by dysregulation of LIN41 as its primary target. Furthermore, we identify direct LIN41 target genes regulated on the level of translation or mRNA abundance. Overall design: Total RNA-sequencing time course experiments sampling synchronized worm populations of different genetic backgrounds every two hours over the course of development from late L2/early L3 stage to late L4/Young adult stage.
LIN41 Post-transcriptionally Silences mRNAs by Two Distinct and Position-Dependent Mechanisms.
Cell line, Subject
View SamplesWe perform RNA sequencing and ribosome profiling time course experiments to examine the effect of fully dysregulating all let-7 targets (in let-7(n2853) animals), partially dysregulating only LIN41 (in lin-41(xe11) animals) or fully dysregulating all let-7 targets while partially dysregulating LIN41 in lin-41(xe11); let-7(n2853) double mutant animals. We conclude that effects on gene expression in let-7 mutant animals are largely and quantitatively explained by dysregulation of LIN41 as its primary target. Furthermore, we identify direct LIN41 target genes regulated on the level of translation or mRNA abundance. Overall design: Ribosome profiling time course experiments sampling synchronized worm populations of different genetic backgrounds every two hours over the course of development from late L2/early L3 stage to late L4/Young adult stage.
LIN41 Post-transcriptionally Silences mRNAs by Two Distinct and Position-Dependent Mechanisms.
Cell line, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Altering TET dioxygenase levels within physiological range affects DNA methylation dynamics of HEK293 cells.
Specimen part, Cell line, Treatment
View SamplesWe compared TET1 and TET3 overexpressing cells to uninduced cells with endogenous levels of the respective transcript to determine global gene expression changes.
Altering TET dioxygenase levels within physiological range affects DNA methylation dynamics of HEK293 cells.
Specimen part, Treatment
View SamplesWe compared TET triple knockdown cells to control cells treated with non-targeting siRNAs to determine global gene expression changes.
Altering TET dioxygenase levels within physiological range affects DNA methylation dynamics of HEK293 cells.
Cell line, Treatment
View SamplesPrimary pre-B acute lymphoblastic (ALL) cells do not proliferate long-term ex vivo without the presence of stromal support. We developed and use an ex vivo co-culture model, consisting of mouse leukemic pre-B Bcr/Abl-expressing ALL cells grown with mitotically inactivated mouse embryonic fibroblasts (MEFs). This system provides a generic type of environmentally-mediated protection to the ALL cells, because when the ALL cells are treated with a moderate dose of a therapeutic drug, drug-resistant ALL cells can be recovered after a 1-2 week period of culture. Some of the factors produced by stromal cells that provide protection to ALL cells have been identified. However, it is unclear if the presence of drug-treated ALL cells affects the stromal fibroblasts. The current study was initiated to examine this using expression profiling on the irradiated MEFs.
Expression of cassini, a murine gamma-satellite sequence conserved in evolution, is regulated in normal and malignant hematopoietic cells.
Specimen part
View Samples