Weiler Karen S, Chatterjee S
Department of Biology, West Virginia University, Morgantown, West Virginia 26506, USA.
Genetics. 2009 May;182(1):145-59. doi: 10.1534/genetics.109.101386. Epub 2009 Mar 16.
The D1 protein is a high mobility group A (HMGA)-like nonhistone chromosomal protein with primary localization to certain AT-rich satellite DNA sequences within heterochromatin. The binding of D1 to euchromatic sequences is less studied and the functional significance of its chromosomal associations is unclear. By taking advantage of existing P-insertion alleles of the D1 gene, I generated D1 null mutations to investigate the phenotypic effect of loss of the D1 gene. In contrast to a previous report, I determined that the D1 gene is not essential for viability of Drosophila melanogaster, and moreover, that loss of D1 has no obvious phenotypic effects. My tests for an effect of D1 mutations on PEV revealed that it is not a suppressor of variegation, as concluded by other investigators. In fact, the consequence of loss of D1 on one of six variegating rearrangements tested, T(2;3)Sb(V), was dominant enhancement of PEV, suggesting a role for the protein in euchromatic chromatin structure and/or transcription. A study of D1 protein sequence conservation highlighted features shared with mammalian HMGA proteins, which function as architectural transcription factors.
D1蛋白是一种高迁移率族A（HMGA）样非组蛋白染色体蛋白，主要定位于异染色质内某些富含AT的卫星DNA序列。D1与常染色质序列的结合研究较少，其染色体关联的功能意义尚不清楚。利用现有的D1基因P插入等位基因，我产生了D1无效突变，以研究D1基因缺失的表型效应。与之前的一份报告相反，我确定D1基因对于黑腹果蝇的生存力并非必不可少，此外，D1的缺失没有明显的表型效应。我对D1突变对位置效应斑驳（PEV）影响的测试表明，它不是如其他研究者所认为的斑驳抑制因子。事实上，在所测试的六个斑驳重排之一T(2;3)Sb(V)中，D1缺失的结果是PEV的显性增强，这表明该蛋白在常染色质染色质结构和/或转录中起作用。一项对D1蛋白序列保守性的研究突出了与哺乳动物HMGA蛋白共有的特征，后者作为结构转录因子发挥作用。
