The Caenorhabditis elegans somatic gonad was the first organ to have its cell lineage determined, and the gonadal lineages of the two sexes differ greatly in their pattern of cell divisions, cell migration and cell types. Despite much study, the genetic pathways that direct early gonadal development and establish its sexual dimorphism remain largely unknown, with just a handful of regulatory genes identified from genetic screens. To help define the genetic networks that regulate gonadal development, we employed cell-specific RNA-seq. We identified transcripts present in Z1/Z4 or Z1/Z4 daughter cells in each sex at the onset of somatic gonadal sexual differentiation. For comparison, transcripts were identified in whole animals at both time points. Pairwise comparisons of samples identified several hundred gonad-enriched transcripts, including most known Z1/Z4-enriched mRNAs, and reporter analysis confirmed the effectiveness of this approach. Prior to the Z1/Z4 division few sex-biased Z1/Z4 transcripts were detectable, but less than six hours later, we identified more than 250 sex-biased transcripts in the Z1/Z4 daughters, of which about a third were enriched in the somatic gonad cells compared to cells from whole animals. This indicates that a robust sex-biased developmental program, some of it gonad-specific, initiates in these cells around the time of the first Z1/Z4 division. Cell-specific analysis also identified approximately 70 previously unannotated mRNA isoforms that are enriched in Z1/Z4 or their daughters. Our data suggest that early sex differentiation in the gonad is controlled by a relatively small suite of differentially expressed genes, even after dimorphism has become apparent. Overall design: 20 total sample: two time points, two sexes, and gonadal cells or whole animals. The earlier time point was collected in triplicate and was harvested 9.5 hours after starved, hatched L1s were fed. The later time point was collected in duplicate and was harvested 15 hour after starved, hatched L1 were fed. Replicates of either dissociated whole animals or gonadal cells (Z1/Z4 or Z1/Z4 daughter) from both male and hermaphrodites were harvested for each time point.
Cell-Specific mRNA Profiling of the Caenorhabditis elegans Somatic Gonadal Precursor Cells Identifies Suites of Sex-Biased and Gonad-Enriched Transcripts.
Sex, Specimen part, Subject, Time
View SamplesIn mammals, a key transition in spermatogenesis is the exit from spermatogonial differentiation and mitotic proliferation and the entry into spermatocyte differentiation and meiosis. Although several genes that regulate this transition have been identified, how it is controlled and coordinated remains poorly understood. Here we examine the role in male gametogenesis of the Doublesex-related gene Dmrt6 (Dmrtb1) and find that Dmrt6 plays a critical role in directing germ cells through the mitotic to meiotic germ cell transition. DMRT6 protein is expressed in late mitotic spermatogonia. In mice of the C57BL/6J strain a null mutation in Dmrt6 disrupts spermatogonial differentiation, causing expression in inappropriate cell types of spermatogonial differentiation factors including SOHLH1, SOHLH2 and DMRT1 and the meiotic initiation factor STRA8 and causing most late spermatogonia to undergo apoptosis. In mice of the 129Sv background, most Dmrt6 mutant spermatogonia can complete differentiation and enter meiosis, but they show defects in chromosome pairing, establishment of the XY body, and processing of recombination foci, and mainly arrest in mid-pachynema. mRNA profiling of Dmrt6 mutant testes together with DMRT6 ChIP-seq suggest that DMRT6 represses genes involved in spermatogonial differentiation and activates genes required for meiotic prophase. Our results indicate that Dmrt6 plays a key role in coordinating the transition in gametogenic programs from spermatogonial differentiation and mitosis to spermatocyte development and meiosis. Overall design: Six samples for RNA-Seq with three biological replicates in each group. Two samples for ChIP-Seq (one input and one ChIP).
The mammalian Doublesex homolog DMRT6 coordinates the transition between mitotic and meiotic developmental programs during spermatogenesis.
No sample metadata fields
View SamplesDmrt1 (doublesex and mab-3 related transcription factor 1) is a conserved transcriptional regulator of male differentiation required for testicular development in vertebrates. This study examines the result of conditional removal of Dmrt1 from Sertoli cells in P28 testis tissue.
DMRT1 prevents female reprogramming in the postnatal mammalian testis.
Sex, Specimen part
View SamplesRetinoic acid (RA) is a potent inducer of cell differentiation and plays an essential role in sex-specific germ cell development in the mammalian gonad. RA is essential for male gametogenesis and hence fertility. However, RA can also disrupt sexual cell fate in somatic cells of the testis, promoting transdifferentiation of male Sertoli cells to female granulosa-like cells when the male sexual regulator Dmrt1 is absent. The feminizing ability of RA in the somatic testis suggests that RA might normally play a role in somatic cell differentiation or cell fate maintenance in the ovary. To test for this possibility we disrupted RA signaling in somatic cells of the early fetal ovary using three genetic strategies and one pharmaceutical approach. We found that deleting all three RA receptors (RARs) in the XX somatic gonad at the time of sex determination did not significantly affect ovarian differentiation, follicle development, or female fertility. Transcriptome analysis of adult triple mutant ovaries revealed remarkably little effect on gene expression in the absence of somatic RAR function. Likewise, deletion of three RA synthesis enzymes (Aldha1-3) at the time of sex determination did not masculinize the ovary. A dominant-negative RAR transgene altered granulosa cell proliferation, likely due to interference with a non-RA signaling pathway, but did not affect granulosa cell specification or fertility. Finally, culture of fetal XX gonads with an RAR antagonist blocked germ cell meiotic initiation but did not disrupt sex-biased gene expression. We conclude that RA signaling, although crucial in the ovary for meiotic initiation, is not required for granulosa cell specification, differentiation, or reproductive function. Overall design: Ovaries from six week old mice with five replicates in each of two genotypes were analyzed by RNA-Seq
Retinoic acid signaling is dispensable for somatic development and function in the mammalian ovary.
Age, Specimen part, Cell line, Subject
View SamplesDmrt1 (doublesex and mab-3 related transcription factor 1) is a conserved transcriptional regulator of male differentiation required for testicular development in vertebrates. In mice of the 129Sv strain, loss of Dmrt1 causes a high incidence of teratomas. Mutant 129Sv germ cells undergo apparently normal differentiation up to embryonic day 13.5 (E13.5), but some cells fail to arrest mitosis and ectopically express pluripotency markers. Expression analysis and chromatin immunoprecipitation identified DMRT1 target genes whose misexpression may underly teratoma formation.
The DM domain protein DMRT1 is a dose-sensitive regulator of fetal germ cell proliferation and pluripotency.
Specimen part
View SamplesWe use gene expression data to provide a three-faceted analysis on the links between molecular subclasses of glioblastima, epithelial-to mesenchymal transition (EMT) and CD133 cell surface protein. The contribution of this paper is three-folded: First, we used a newly identified signature for epithelial-to-mesenchymal transition in human mammary epithelial cells, and demonstrated that genes in this signature have significant overlap with genes differentially expressed in all known GBM subtypes. However, the overlap between the genes up-regulated in the mesenchymal subtype of GBM and in the EMT signature was more significant than other GBM subtypes. Second, we provided evidence that there is a negative correlation between the genetic signature of EMT and that of CD133 cell surface protein, a putative marker for neural stem cells. Third, we studied the correlation between GBM molecular subtypes and the genetic signature of CD133 cell surface protein. We demonstrated that the mesenchymal and neural subtypes of GBM have the strongest correlations with the CD133 genetic signature. While the mesenchymal subtype of GBM demonstrates similarity with the signatures of both EMT and CD133, it also demonstrates some differences with each of these signatures that is partly due to the fact that the signatures of EMT and CD133 are inversely related to each other. Taken together this data sheds light on role of the mesenchymal transition and neural stem cells, and their mutual interaction, in molecular subtypes of glioblastoma multiforme.
Investigating the link between molecular subtypes of glioblastoma, epithelial-mesenchymal transition, and CD133 cell surface protein.
Specimen part
View SamplesThe canonical Wnt pathway plays a central role in stem cell maintenance, differentiation and proliferation in the intestinal epithelium. Constitutive, aberrant activity of the TCF4/ß-catenin transcriptional complex is the primary transforming factor in colorectal cancer. Despite significant recent inroads, the full complement of Wnt target genes and the mechanisms of regulation remain incompletely understood. Here we identify a nuclear long non-coding RNA, termed WiNTRLINC1, as a direct target of TCF4/ß-catenin in colorectal cancer cells. WiNTRLINC1 positively regulates the expression of its close neighbor ASCL2, a transcription factor that controls intestinal stem cell fate. WiNTRLINC1 interacts with TCF4/ß-catenin to mediate the juxtaposition/physical contact of its own promoter with the regulatory regions of ASCL2. ASCL2, in turn, regulates WiNTRLINC1 expression. This feedforward regulatory loop controls stem cell-related gene expression and is highly amplified in colorectal cancer. Overall design: Derivatives of Ls174T colon cancer cells, overexpressing the Tet repressor were used for the construction of inducible overexpressing a shRNA against the WiNTRLINC1 long non coding RNA upon treatment with doxyxycline. siRNAs against WiNTRLINC1 were designed with the siDesign center tool from Dharmacon and their sequences were used for the construction of the shRNA stem loop structure as described in EMBO Rep. 2003 Jun;4(6):609-15. The modified pTER vector was used as a backbone for constructing the shRNA cassette as described in EMBO Rep. 2003 Jun;4(6):609-15. Positive cell clones were screened with RT-PCR in order to validate the efficiency of the knockdown of WiNTRLINC1. The Ls174T derivative cell line inducibly overexpressing a shRNA against ASCL2 has been described previously in Cell. 2009 Mar 6;136(5):903-12. RNA deep sequencing was performed in the WiNTRLINC1 KD and ASCL2 KD cells compared to controls cells in order to detect changes in gene expression due to the loss of either WiNTRLINC1 or ASCL2.
A Positive Regulatory Loop between a Wnt-Regulated Non-coding RNA and ASCL2 Controls Intestinal Stem Cell Fate.
No sample metadata fields
View SamplesGoal was to identify yeast genes whose expression changed as a function of the shift from growth in bulk culture to growth in an air-liquid interfacial biofilm.
Ethanol-independent biofilm formation by a flor wine yeast strain of Saccharomyces cerevisiae.
Specimen part
View SamplesComparison of gene expression profiles from C. elegans wildtype strain (N2) treated with L4440 and T25B9.1 RNAi for 5 days after L4 larvae stage. Jena Centre for Systems Biology of Ageing - JenAge (ww.jenage.de) Overall design: 6 samples in 2 groups: N2, L4440 5 days (3 Samples); N2, T25B9.1 5 days (3 Samples)
Impairing L-Threonine Catabolism Promotes Healthspan through Methylglyoxal-Mediated Proteohormesis.
Sex, Age, Specimen part, Cell line, Subject
View SamplesBackground: Arsenite is one of the most toxic chemical substances known and is assumed to exert detrimental effects on viability even at lowest concentrations. By contrast and unlike higher concentrations, we here find that exposure to low-dose arsenite promotes growth of cultured mammalian cells. In the nematode C. elegans, low-dose arsenite promotes resistance against thermal and chemical stressors, and extends lifespan of this metazoan, whereas higher concentrations reduce longevity. While arsenite causes a transient increase in reactive oxygen species (ROS) levels in C. elegans, co-exposure to ROS scavengers prevents the lifespan-extending capabilities of arsenite, indicating that transiently increased ROS levels act as transducers of arsenite effects on lifespan, a process known as mitohormesis. The RNA-seq data comprises 2 biological replicates for worms exposed to 100nM Arsenite 48h after L4 and 2 biological replicates of the same age as controls Jena Centre for Systems Biology of Ageing - JenAge (www.jenage.de) Overall design: 4 samples: 2 mRNA profiles of C.elegans 48h after L4 exposed to Arsenite; 2 mRNA profiles of C.elegans 48h after L4 as controls (H20). The N2 wild type (var. Bristol) strain was used.
Mitochondrial hormesis links low-dose arsenite exposure to lifespan extension.
Specimen part, Treatment, Subject
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