Division of Molecular Biology, Biocenter, Innsbruck Medical University, Fritz-Pregl Strasse 3, 6020 Innsbruck, Austria.
Nucleic Acids Res. 2011 Apr;39(8):3103-15. doi: 10.1093/nar/gkq1298. Epub 2010 Dec 21.
The molecular motor protein CHD1 has been implicated in the regulation of transcription and in the transcription-independent genome-wide incorporation of H3.3 into paternal chromatin in Drosophila melanogaster. A key feature of CHD1 is the presence of two chromodomains, which can bind to histone H3 methylated at lysine 4 and thus might serve to recruit and/or maintain CHD1 at the chromatin. Here, we describe genetic and biochemical approaches to the study of the Drosophila CHD1 chromodomains. We found that overall localization of CHD1 on polytene chromosomes does not appreciably change in chromodomain-mutant flies. In contrast, the chromodomains are important for transcription-independent activities of CHD1 during early embryonic development as well as for transcriptional regulation of several heat shock genes. However, neither CHD1 nor its chromodomains are needed for RNA polymerase II localization and H3K4 methylation but loss of CHD1 decreases transcription-induced histone eviction at the Hsp70 gene in vivo. Chromodomain mutations negatively affect the chromatin assembly activities of CHD1 in vitro, and they appear to be involved in linking the ATP-dependent motor to the chromatin assembly function of CHD1.
分子马达蛋白 CHD1 被认为参与了转录的调节，以及在黑腹果蝇中 H3.3 在转录非依赖性的情况下被广泛整合到父本染色质中。CHD1 的一个关键特征是存在两个 chromodomains，它可以结合到赖氨酸 4 甲基化的组蛋白 H3，因此可能有助于将 CHD1 募集到或维持在染色质上。在这里，我们描述了研究果蝇 CHD1 chromodomains 的遗传和生化方法。我们发现，在 chromodomain 突变体果蝇中，CHD1 在多线染色体上的总体定位并没有明显改变。相比之下，chromodomains 对于 CHD1 在早期胚胎发育过程中的转录非依赖性活性以及几个热休克基因的转录调控非常重要。然而，CHD1 及其 chromodomains 都不需要 RNA 聚合酶 II 的定位和 H3K4 甲基化，但 CHD1 的缺失会减少体内 HSP70 基因转录诱导的组蛋白驱逐。chromodomain 突变在体外显著影响了 CHD1 的染色质组装活性，并且它们似乎参与了将 ATP 依赖性马达与 CHD1 的染色质组装功能连接起来。
