Ordered assembly of roX RNAs into MSL complexes on the dosage-compensated X chromosome in Drosophila
Ordered assembly of roX RNAs into MSL complexes on the dosage-compensated X chromosome in Drosophila
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DOI：
10.1016/s0960-9822(00)00311-0
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发表时间：
2000-02-10
期刊：
影响因子：
9.2
通讯作者：
Kuroda, MI
中科院分区：
文献类型：
--
作者：
Meller, VH;Gordadze, PR;Kuroda, MI
背景资料：在雄性果蝇中，X染色体被转录上调以实现剂量补偿，这一过程取决于MSL蛋白与X染色体的结合。在最近的研究中已经提出了非编码RNA的作用。roX 1和roX 2 RNA是男性特异性的非编码RNA，由剂量补偿男性X染色体产生，也发现与剂量补偿男性X染色体相关。无论roX RNA的物理部分的MSL complex尚未resolved.Results：我们发现，roX RNA与MSL蛋白共定位，是非常不稳定的，除非MSL复合物共表达，这表明一个物理相互作用。我们能够免疫沉淀roX 2 RNA从男性组织培养细胞与抗体的蛋白质Msl 1和Mle，符合与MSL复合物的整体关联。roX 1和roX 2 RNA在突变体中的定位表明了MSL复合物组装的顺序，其中roX 2 RNA在需要Mle解旋酶的过程中早期掺入。我们还发现，roX 2基因，如roX 1，是一个成核网站MSL复杂的扩展到侧翼染色质cis.Conclusions：我们的研究结果支持一个模型，其中MSL蛋白组装在特定的染色质进入网站（包括roX 1和roX 2基因）; roX RNA加入复杂的合成网站;和完整的复合物传播顺式剂量补偿X染色体上的大多数基因。
Background: In the male Drosophila, the X chromosome is transcriptionally upregulated to achieve dosage compensation, in a process that depends on association of the MSL proteins with the X chromosome. A role for non-coding RNAs has been suggested in recent studies. The roX1 and roX2 RNAs are male-specific, non-coding RNAs that are produced by, and also found associated with, the dosage-compensated male X chromosome. Whether roX RNAs are physically part of the MSL complex has not been resolved.Results: We found that roX RNAs colocalize with the MSL proteins and are highly unstable unless the MSL complex is coexpressed, suggesting a physical interaction. We were able to immunoprecipitate roX2 RNA from male tissue-culture cells with antibodies to the proteins Msl1 and Mle, consistent with an integral association with MSL complexes. Localization of roX1 and roX2 RNAs in mutants indicated an order of MSL-complex assembly in which roX2 RNA is incorporated early in a process requiring the Mle helicase. We also found that the roX2 gene, like roX1, is a nucleation site for MSL complex spreading into flanking chromatin in cis.Conclusions: Our results support a model in which MSL proteins assemble at specific chromatin entry sites (including the roX1 and roX2 genes); the roX RNAs join the complex at their sites of synthesis; and complete complexes spread in cis to dosage compensate most genes on the X chromosome.