Increased gene dosage and mRNA expression from chromosomal duplications in Caenorhabditis elegans.

Isolation of copy number variations and chromosomal duplications at high frequency in the laboratory suggested that Caenorhabditis elegans tolerates increased gene dosage. Here, we addressed if a general dosage compensation mechanism acts at the level of mRNA expression in C. elegans.

Binding of an -Specific Condensin Correlates with a Reduction in Active Histone Modifications at Gene Regulatory Elements.

Condensins are evolutionarily conserved protein complexes that are required for chromosome segregation during cell division and genome organization during interphase. In , a specialized condensin, which forms the core of the dosage compensation complex (DCC), binds to and represses chromosome transcription. Here, we analyzed DCC localization and the effect of DCC depletion on histone modifications, transcription factor binding, and gene expression using chromatin immunoprecipitation sequencing and mRNA sequencing.

Caenorhabditis elegans Dosage Compensation: Insights into Condensin-Mediated Gene Regulation.

Recent work demonstrating the role of chromosome organization in transcriptional regulation has sparked substantial interest in the molecular mechanisms that control chromosome structure. Condensin, an evolutionarily conserved multisubunit protein complex, is essential for chromosome condensation during cell division and functions in regulating gene expression during interphase. In Caenorhabditis elegans, a specialized condensin forms the core of the dosage compensation complex (DCC), which specifically binds to and represses transcription from the hermaphrodite X chromosomes.

Cooperation between a hierarchical set of recruitment sites targets the X chromosome for dosage compensation.

In many organisms, it remains unclear how X chromosomes are specified for dosage compensation, since DNA sequence motifs shown to be important for dosage compensation complex (DCC) recruitment are themselves not X-specific. Here, we addressed this problem in . We found that the DCC recruiter, SDC-2, is required to maintain open chromatin at a small number of primary DCC recruitment sites, whose sequence and genomic context are X-specific.

Developmental Dynamics of X-Chromosome Dosage Compensation by the DCC and H4K20me1 in C. elegans.

In Caenorhabditis elegans, the dosage compensation complex (DCC) specifically binds to and represses transcription from both X chromosomes in hermaphrodites. The DCC is composed of an X-specific condensin complex that interacts with several proteins. During embryogenesis, DCC starts localizing to the X chromosomes around the 40-cell stage, and is followed by X-enrichment of H4K20me1 between 100-cell to comma stage.

Sex-biased gene expression and evolution of the x chromosome in nematodes.

Studies of X chromosome evolution in various organisms have indicated that sex-biased genes are nonrandomly distributed between the X and autosomes. Here, to extend these studies to nematodes, we annotated and analyzed X chromosome gene content in four Caenorhabditis species and in Pristionchus pacificus. Our gene expression analyses comparing young adult male and female mRNA-seq data indicate that, in general, nematode X chromosomes are enriched for genes with high female-biased expression and depleted of genes with high male-biased expression.

Genome-wide analysis of condensin binding in Caenorhabditis elegans.

Background: Condensins are multi-subunit protein complexes that are essential for chromosome condensation during mitosis and meiosis, and play key roles in transcription regulation during interphase. Metazoans contain two condensins, I and II, which perform different functions and localize to different chromosomal regions. Caenorhabditis elegans contains a third condensin, I(DC), that is targeted to and represses transcription of the X chromosome for dosage compensation.