Recruitment of C. elegans dosage compensation proteins for gene-specific versus chromosome-wide repression.
نویسندگان
چکیده
In C. elegans, an X-chromosome-wide regulatory process compensates for the difference in X-linked gene dose between males (XO) and hermaphrodites (XX) by equalizing levels of X-chromosome transcripts between the sexes. To achieve dosage compensation, a large protein complex is targeted to the X chromosomes of hermaphrodites to reduce their expression by half. This repression complex is also targeted to a single autosomal gene, her-1. By silencing this male-specific gene, the complex induces hermaphrodite sexual development. Our analysis of the atypical dosage compensation gene dpy-21 revealed the first molecular differences in the complex that achieves gene-specific versus chromosome-wide repression. dpy-21 mutations, shown here to be null, cause elevated X-linked gene expression in XX animals, but unlike mutations in other dosage compensation genes, they do not cause extensive XX-specific lethality or disrupt the stability or targeting of the dosage compensation complex to X. Nonetheless, DPY-21 is a member of the dosage compensation complex and localizes to X chromosomes in a hermaphrodite-specific manner. However, DPY-21 is the first member of the dosage compensation complex that does not also associate with her-1. In addition to a difference in the composition of the complex at her-1 versus X, we also found differences in the targeting of the complex to these sites. Within the complex, SDC-2 plays the lead role in recognizing X-chromosome targets, while SDC-3 plays the lead in recognizing her-1 targets.
منابع مشابه
Recruitment and spreading of the C. elegans dosage compensation complex along X chromosomes.
To achieve X-chromosome dosage compensation, organisms must distinguish X chromosomes from autosomes. We identified multiple, cis-acting regions that recruit the Caenorhabditis elegans dosage compensation complex (DCC) through a search for regions of X that bind the complex when detached from X. The DCC normally assembles along the entire X chromosome, but not all detached regions recruit the c...
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Dosage compensation is a chromosome-wide regulatory process that balances X-chromosome gene expression between males and females that have different complements. Recent advances have clarified the molecular nature of the Caenorhabditis elegans sex-determination signal, which tallies X-chromosome number relative to the ploidy and controls both the choice of sexual fate and the process of dosage ...
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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 C. elegans. We found that the DCC recruiter, SDC-2, is required to maintain open chromatin at a small number of primary DCC recruitment si...
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ورودعنوان ژورنال:
- Development
دوره 130 26 شماره
صفحات -
تاریخ انتشار 2003