DDP1, a heterochromatin-associated multi-KH-domain protein of Drosophila melanogaster, interacts specifically with centromeric satellite DNA sequences
DDP1, a heterochromatin-associated multi-KH-domain protein of Drosophila melanogaster, interacts specifically with centromeric satellite DNA sequences
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DOI：
10.1128/mcb.20.11.3860-3869.2000
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发表时间：
2000-06-01
影响因子：
5.3
通讯作者：
Azorín, F
中科院分区：
文献类型：
--
作者：
Cortés, A;Azorín, F
DDP1是果蝇的一种单链核酸结合蛋白，与着丝粒周围异染色质相关。DDP1包含15个连续的KH结构域，与酿酒酵母中高度保守的参与细胞倍性控制的Viglin蛋白同源。根据DDP1与着丝粒果蝇十二星着丝粒富含嘧啶的C链的结合，鉴定和纯化了DDP1。在这里，详细分析了DDP1与十二星C链的相互作用。这种相互作用是特定于序列的。特别是，在天然十二星序列中高度保守的鸟嘌呤残基对于DDP1的有效结合是必不可少的，DDP1的结合也被发现受到DNA底物二级结构的长度和程度的强烈影响。有效的DDP1结合需要大约75到100个核苷酸的最小长度，并且由于缺乏底物的二级结构而变得容易。DDP1还显示出与最丰富的着丝粒果蝇AAGAG卫星的富含嘧啶的非结构链的显著亲和力。与十二卫星C链形成的络合物的化学计量学表明，在DDP1中，15个连续的KH结构域被组织起来，从而定义了两个核酸结合面。这些结果在DDP1对异染色质组织和功能的可能贡献的背景下进行了讨论。
DDP1 is a single-stranded nucleic acid binding protein of Drosophila melanogaster that associates with pericentric heterochromatin. DDP1 contains 15 consecutive KH domains and is homologous to the highly conserved vigilin proteins that, in Saccharomyces cerevisiae, are involved in the control of cell ploidy, DDP1 was identified and purified on the basis of its binding to the pyrimidine-rich C strand of the centromeric Drosophila dodeca-satellite. Here, the interaction of DDP1 with the dodeca-satellite C strand was analyzed in detail. This interaction is sequence specific. In particular, a guanine residue which is highly conserved in natural dodeca-satellite sequences was found to be essential for the efficient binding of DDP1, DDP1 binding was also found to be strongly influenced by the length and extent of secondary structure of the DNA substrate. Efficient DDP1 binding required a minimal length of about 75 to 100 nucleotides and was facilitated by the lack of secondary structure of the substrate. DDP1 also showed a significant affinity for the unstructured pyrimidine-rich strand of the most abundant centromeric Drosophila AAGAG satellite. The stoichiometry of the complexes formed with the dodeca-satellite C strand suggests that, in DDP1, the 15 consecutive KH domains are organized such that they define two nucleic acid binding surfaces. These results are discussed in the context of the possible contribution of DDP1 to heterochromatin organization and function.