Divergent evolution toward sex chromosome-specific gene regulation in Drosophila

Villa, Raffaella; Jagtap, Pravin Kumar Ankush; Thomae, Andreas W.; Sparr, Aline Campos; Forne, Ignasi; Hennig, Janosch; Straub, Tobias und Becker, Peter B. (2021): Divergent evolution toward sex chromosome-specific gene regulation in Drosophila. In: Genes & Development, Bd. 35, Nr. 13-14: S. 1055-1070

Abstract

The dosage compensation complex (DCC) of Drosophila identifies its X-chromosomal binding sites with exquisite selectivity. The principles that assure this vital targeting are known from the D. melanogaster model: DCC-intrinsic specificity of DNA binding, cooperativity with the CLAMP protein, and noncoding roX2 RNA transcribed from the X chromosome. We found that in D. virilis, a species separated from melanogaster by 40 million years of evolution, all principles are active but contribute differently to X specificity. In melanogaster, the DCC subunit MSL2 evolved intrinsic DNA-binding selectivity for rare PionX sites, which mark the X chromosome. In virilis, PionX motifs are abundant and not X-enriched. Accordingly, MSL2 lacks specific recognition. Here, roX2 RNA plays a more instructive role, counteracting a nonproductive interaction of CLAMP and modulating DCC binding selectivity. Remarkably, roX2 triggers a stable chromatin binding mode characteristic of DCC. Evidently, X-specific regulation is achieved by divergent evolution of protein, DNA, and RNA components.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Medizin
• Themengebiete: 600 Technik, Medizin, angewandte Wissenschaften > 610 Medizin und Gesundheit
• ISSN: 0890-9369
• Sprache: Englisch