Incorporation of the noncoding roX RNAs alters the chromatin-binding specificity of the Drosophila MSLI/MSL2 complex
Incorporation of the noncoding roX RNAs alters the chromatin-binding specificity of the Drosophila MSLI/MSL2 complex
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DOI：
10.1128/mcb.00910-07
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发表时间：
2008-02-01
影响因子：
5.3
通讯作者：
Scott, Maxwell J.
中科院分区：
文献类型：
--
作者：
Li, Fang;Schlemann, Anja H.;Scott, Maxwell J.
雄性特异性致死蛋白-RNA复合物是果蝇X染色体剂量补偿所必需的。MSL 2和MSL 1蛋白形成复合物，并且对于X染色体结合是必需的。此外，MSL复合物必须整合至少一个非编码roX RNA，以进行正常的X染色体结合。在这里，我们发现MSL 2的氨基末端环指结构域作为一个复合物与MSL 1结合到异染色质染色中心和染色体臂上的一些位点。这种结合需要与先前显示的MSL 1相同的氨基末端基本基序，该基序对于结合X染色体上的高亲和力位点是必需的。虽然MSL 2的RING指结构域足以增加roX 1在女性中的表达，但roX 2的激活需要羧基末端结构域中的基序。与X染色体上数百个位点的结合以及roX RNA有效掺入MSL复合物中需要MSL 2羧基末端结构域中富含脯氨酸的碱性基序。我们认为，将roX RNA掺入MSL复合物中改变了由MSL 1和MSL 2的氨基末端结构域形成的染色质结合模块的结合特异性。
The male-specific lethal (MSL) protein-RNA complex is required for X chromosome dosage compensation in Drosophila melanogaster. The MSL2 and MSL1 proteins form a complex and are essential for X chromosome binding. In addition, the MSL complex must integrate at least one of the noncoding roX RNAs for normal X chromosome binding. Here we find the amino-terminal RING finger domain of MSL2 binds as a complex with MSL1 to the heterochromatic chromocenter and a few sites on the chromosome arms. This binding required the same amino-terminal basic motif of MSL1 previously shown to be essential for binding to high-affinity sites on the X chromosome. While the RING finger domain of MSL2 is sufficient to increase the expression of roX1 in females, activation of roX2 requires motifs in the carboxyl-terminal domain. Binding to hundreds of sites on the X chromosome and efficient incorporation of the roX RNAs into the MSL complex require proline-rich and basic motifs in the carboxyl-terminal domain of MSL2. We suggest that incorporation of the roX RNAs into the MSL complex alters the binding specificity of the chromatin-binding module formed by the amino-terminal domains of MSL1 and MSL2.