Kelley R L, Meller V H, Gordadze P R, Roman G, Davis R L, Kuroda M I
Department of Cell Biology, Baylor College of Medicine, Houston, Texas 77030, USA.
Cell. 1999 Aug 20;98(4):513-22. doi: 10.1016/s0092-8674(00)81979-0.
The multisubunit MSL dosage compensation complex binds to hundreds of sites along the Drosophila single male X chromosome, mediating its hypertranscription. The male X chromosome is also coated with noncoding roX RNAs. When either msl3, mle, or mof is mutant, a partial MSL complex is bound at only approximately 35 unusual sites distributed along the X. We show that two of these sites are the roX1 and roX2 genes and postulate that one of their functions is to provide entry sites for the MSL complex to recognize the X chromosome. The roX1 gene provides a nucleation site for extensive spreading of the MSL complex into flanking chromatin even when moved to an autosome. The spreading can occur in cis or in trans between paired homologs. We present a model for how the dosage compensation complex recognizes X chromatin.
多亚基MSL剂量补偿复合体结合在果蝇单条雄性X染色体上的数百个位点，介导其超转录。雄性X染色体也被非编码roX RNA覆盖。当msl3、mle或mof发生突变时，部分MSL复合体仅结合在沿X染色体分布的约35个不同寻常的位点上。我们发现其中两个位点是roX1和roX2基因，并推测它们的功能之一是为MSL复合体识别X染色体提供进入位点。即使将roX1基因转移到常染色体上，它也能为MSL复合体广泛扩散到侧翼染色质提供一个成核位点。这种扩散可以在顺式或配对同源染色体之间的反式中发生。我们提出了一个关于剂量补偿复合体如何识别X染色质的模型。
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