Recruitment of the male-specific lethal (MSL) dosage compensation complex to an autosomally integrated roX chromatin entry site correlates with an increased expression of an adjacent reporter gene in male Drosophila
Recruitment of the male-specific lethal (MSL) dosage compensation complex to an autosomally integrated roX chromatin entry site correlates with an increased expression of an adjacent reporter gene in male Drosophila
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DOI：
10.1074/jbc.m103008200
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发表时间：
2001-08-24
影响因子：
4.8
通讯作者：
Scott, MJ
中科院分区：
文献类型：
--
作者：
Henry, RA;Tews, B;Scott, MJ
果蝇通过使雄性中大多数 X 连锁基因的转录加倍来进行剂量补偿（均衡 X 连锁基因产物）。 MSL（雄性特异性致死）核糖核蛋白复合物由至少五种蛋白质和两种非编码 RNA（roX1 和 roX2）组成，对于这种转录反应至关重要。最近的研究表明，X 连锁的 roX1 和 roX2 基因均含有至少一个 MSL 复合体的染色质进入位点。在这项研究中，我们表明，在受组成型犰狳启动子（arm-lacZ）控制的绝缘lacZ报告基因上游插入roX1或roX2 DNA序列，会导致雄性中lacZ的表达显着升高。然而，仅在一些携带 roX1-arm-lacZ 或 roX2-arm-lacZ 转基因常染色体插入的品系中观察到完全补偿，即雄性相对于雌性的 lacZ 表达精确加倍。此外，我们发现包含 MSL 结合位点的 roX1 的 419 个碱基对片段足以引起雄性中 lacZ 表达的适度升高，但这种反应明显低于全长 roX1 cDNA 所获得的反应。这是首次直接证明在常染色体上插入 MSL 染色质进入位点会导致男性中进入位点附近基因的表达升高。
Drosophila dosage compensate (equalize X-linked gene products) by doubling the transcription of most X-linked genes in males. The MSL (male-specific lethal) ribonucleoprotein complex consisting of at least five proteins and two non-coding RNAs (roX1 and roX2) is essential for this transcription response. Recently it has been shown that the X-linked roX1 and roX2 genes each contain at least one chromatin entry site for the MSL complex. In this study we show that insertion of either roX1 or roX2 DNA sequences, upstream of an insulated lacZ reporter gene controlled with the constitutive armadillo promoter (arm-lacZ), results in a significant elevation of expression of lacZ in males. However, full compensation, that is a precise doubling of lacZ expression in males relative to females, was only observed in some lines carrying autosomal insertions of either roX1-arm-lacZ or roX2-arm-lacZ transgenes. Furthermore, we found that a 419-base pair fragment of roX1 that contains an MSL binding site was sufficient to cause a modest elevation of expression of lacZ in males, but this response was significantly less than obtained with a full-length roX1 cDNA. This is the first direct demonstration that insertion of an MSL chromatin entry site on an autosome results in elevated expression in males of genes near the entry site.