Drosophila DDP1, a multi-KH-domain protein, contributes to centromeric silencing and chromosome segregation
Drosophila DDP1, a multi-KH-domain protein, contributes to centromeric silencing and chromosome segregation
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DOI：
10.1016/j.cub.2004.09.024
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发表时间：
2004-09-21
期刊：
影响因子：
9.2
通讯作者：
Azorín, F
中科院分区：
文献类型：
--
作者：
Huertas, D;Cortés, A;Azorín, F
背景资料：黑腹果蝇DDP 1蛋白是一种高度进化保守的蛋白，其特征在于存在15个串联组织的KH结构域，已知其介导与单链核酸（RNA和ssDNA）的高亲和力结合。与其分子组织一致，DDP 1在体外以高亲和力结合单链核酸。先前的研究表明，在多线染色体中，DDP 1与染色中心异染色质相关，这表明DDP 1对异染色质的形成和/或维持有贡献。本文在分析了现有文献的基础上，通过分析与亚纯型ddp 1（15-1）相关的表型，确定了DDP 1对异染色质结构和功能特性的实际贡献通过插入ddp 1第二内含子中的P元件的移动而产生的突变。ddp 1（15.1）在In（1）w（m4）的杂色重排中以及在显示hsp 70-白色（+）转基因的杂色表达的几个转基因系中表现为PEV的显性抑制剂。在来自纯合ddp 1（15.1）幼虫的多线染色体中，组蛋白H3-K9甲基化和HP 1在染色中心异染色质的沉积强烈减少。我们的研究结果还表明，当母体贡献的DDP 1减少，染色体凝聚和分离受到损害。此外，在ddp 1（15.1）突变的背景下，传输的非必需的Dp 1187 minichromosomeisreduced.Conclusions：我们得出结论，DDP 1有助于异染色质的结构和功能特性。这些结果在当前异染色质形成和维持模型的背景下进行了讨论;在这些模型中，HP 1沉积依赖于H3-K9甲基化，反过来，这需要RNAi途径的贡献。
Background: The Drosophila melanogaster DDP1 protein is a highly evolutionarily conserved protein that is characterised by the presence of 15 tandemly organized KH domains, known for mediating high-affinity binding to single-stranded nucleic acids (RNA and ssDNA). Consistent with its molecular organization, DDP1 binds single-stranded nucleic acids with high affinity, in vitro. It was shown earlierthat, in polytene chromosomes, DDP1 is found in association with chromocenter heterochromatin, suggesting a contribution to heterochromatin formation and/or maintenance.Results: In this paper, the actual contribution of DDP1 to the structural and functional properties of heterochromatin was determined through the analysis of the phenotypes associated with the hypomorphic ddp1(15-1) mutation that was generated through the mobilization of a P element inserted in the second intron of ddp1. ddp1(15.1) behaves as a dominant suppressor of PEV in the variegated rearrangement In(1)w(m4) as well as in several transgenic lines showing variegated expression of a hsp70-white(+) transgene. In polytene chromosomes from homozygous ddp1(15.1) larvae, histoneH3-K9 methylation and HP1 deposition at chromocentre heterochromatin are strongly reduced. Our results also show that, when the maternal contribution of DDP1 is reduced, chromosome condensation and segregation are compromised. Moreover, in a ddp1(15.1) mutant background, transmission of the nonessential Dp1187 minichromosome is reduced.Conclusions: We conclude that DDP1 contributes to the structural and functional properties of heterochromatin. These results are discussed in the context of current models for the formation and maintenance of heterochromatin; in these models, HP1 deposition depends on H3-K9 methylation that, in turn, requires the contribution of the RNAi pathway.