Division of Biological Sciences, University of Missouri, Columbia, USA.
J Genet Genomics. 2011 Aug 20;38(8):327-32. doi: 10.1016/j.jgg.2011.07.001. Epub 2011 Jul 18.
A set of proteins and noncoding RNAs, referred to as the male specific lethal (MSL) complex, is present on the male X chromosome in Drosophila and has been postulated to be responsible for dosage compensation of this chromosome - the up-regulation of its expression to be equal to that of two X chromosomes in females. This hypothesis is evaluated in view of lesser known aspects of dosage compensation such as the fact that metafemales with three X chromosomes also have equal expression to normal females, which would require a down-regulation of each gene copy. Moreover, when this complex is ectopically expressed in females or specifically targeted to a reporter in males, there is no increase in expression of the genes or targets with which it is associated. These observations are not consistent with the hypothesis that the MSL complex conditions dosage compensation. A synthesis is described that can account for these observations.
一组蛋白质和非编码 RNA，称为雄性特异致死 (MSL) 复合物，存在于果蝇的雄性 X 染色体上，据推测其负责该染色体的剂量补偿 - 上调其表达，使其与雌性中的两条 X 染色体相当。该假说根据剂量补偿的一些鲜为人知的方面进行了评估，例如具有三条 X 染色体的拟雌性也与正常雌性具有相同的表达水平，这需要下调每个基因拷贝。此外，当该复合物在雌性中异位表达或专门针对雄性中的报告基因靶向时，与其相关的基因或靶标没有表达增加。这些观察结果与 MSL 复合物调节剂量补偿的假说不一致。描述了一个可以解释这些观察结果的综合模型。
