Transcriptional repression by nucleosomes but not H1 in reconstituted preblastoderm Drosophila chromatin.
Transcriptional repression by nucleosomes but not H1 in reconstituted preblastoderm Drosophila chromatin.
复制标题
在重建的前胚层果蝇染色质中，核小体而非 H1 抑制转录。
作者：
Raphael Sandaltzopoulos;T. Blank;Peter B. Becker
果蝇胚前胚层提取液中重组的染色质抑制RNA聚合酶II的转录。我们在DNA上组装了有规则间隔的核小体，这些核小体附着在顺磁珠上，能够有效地纯化用于转录研究的染色质模板。我们已经使用诊断盐提取来确定固定染色质的转录抑制主要是由于核小体核心。当纯化的H1结合到染色质中时，导致重复长度增加到200 - 220 bp， H1对转录抑制的贡献可以忽略不计。如果加入更多的H1，则没有得到规则间隔的染色质，只有在这些条件下，H1的转录抑制才明显。我们得出结论，聚合酶II在该系统中有效抑制转录不需要组蛋白H1的存在。
Chromatin reconstituted in an extract from preblastoderm Drosophila embryos represses transcription by RNA polymerase II. We have assembled regularly spaced nucleosomes on DNA attached to paramagnetic beads enabling the efficient purification of chromatin templates for transcription studies. We have used diagnostic salt extractions to establish that transcriptional repression of immobilized chromatin was largely due to nucleosome cores. When purified H1 was incorporated into chromatin, resulting in increased repeat lengths to 200‐220 bp, the contribution of H1 to transcriptional repression was negligible. If more H1 was added no regularly spaced chromatin was obtained and only under these conditions was transcriptional inhibition by H1 apparent. We conclude that efficient repression of transcription by polymerase II in this system does not require the presence of histone H1.