Department of Molecular and Cell Biology, Division of Biochemistry and Molecular Biology, University of California, Berkeley, Berkeley, California, USA.
Mol Cell Biol. 2012 Aug;32(16):3218-27. doi: 10.1128/MCB.00432-12. Epub 2012 Jun 11.
The Drosophila melanogaster Myb-MuvB/dREAM complex (MMB/dREAM) participates in both the activation and repression of developmentally regulated genes and origins of DNA replication. Mutants in MMB subunits exhibit diverse phenotypes, including lethality, eye defects, reduced fecundity, and sterility. Here, we used P-element excision to generate mutations in lin-52, which encodes the smallest subunit of the MMB/dREAM complex. lin-52 is required for viability, as null mutants die prior to pupariation. The generation of somatic and germ line mutant clones indicates that lin-52 is required for adult eye development and for early embryogenesis via maternal effects. Interestingly, the maternal-effect embryonic lethality, larval lethality, and adult eye defects could be suppressed by mutations in other subunits of the MMB/dREAM complex. These results suggest that a partial MMB/dREAM complex is responsible for the lethality and eye defects of lin-52 mutants. Furthermore, these findings support a model in which the Lin-52 and Myb proteins counteract the repressive activities of the other members of the MMB/dREAM complex at specific genomic loci in a developmentally controlled manner.
果蝇的 Myb-MuvB/dREAM 复合物（MMB/dREAM）参与发育调控基因和 DNA 复制起始的激活和抑制。MMB 亚基的突变体表现出多种表型，包括致死性、眼睛缺陷、繁殖力降低和不育。在这里，我们使用 P 元素切除来产生 lin-52 的突变，lin-52 编码 MMB/dREAM 复合物的最小亚基。lin-52 对于生存是必需的，因为缺失突变体在蛹化之前死亡。体细胞和生殖系突变克隆的产生表明 lin-52 对于成年眼睛发育和通过母体效应的早期胚胎发生是必需的。有趣的是，母源效应胚胎致死、幼虫致死和成年眼睛缺陷可以通过 MMB/dREAM 复合物的其他亚基的突变来抑制。这些结果表明，部分 MMB/dREAM 复合物负责 lin-52 突变体的致死性和眼睛缺陷。此外，这些发现支持这样一种模型，即 Lin-52 和 Myb 蛋白以发育控制的方式在特定基因组位置拮抗 MMB/dREAM 复合物的其他成员的抑制活性。
