INTERACTION OF SPATIALLY SEPARATED PROTEIN DNA COMPLEXES FOR CONTROL OF GENE-EXPRESSION - OPERATOR CONVERSIONS
INTERACTION OF SPATIALLY SEPARATED PROTEIN DNA COMPLEXES FOR CONTROL OF GENE-EXPRESSION - OPERATOR CONVERSIONS
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DOI：
10.1073/pnas.85.24.9683
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发表时间：
1988-12-01
影响因子：
11.1
通讯作者：
ADHYA, S
中科院分区：
文献类型：
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作者：
HABER, R;ADHYA, S
两个操纵子在空间上彼此分离并且与启动子分离，当与 Gal 抑制子结合时抑制 gal 操纵子。尽管同时存在 Gal 和 Lac 阻遏物，但将任一 gal 操纵子转换为 lac 操纵子都会导致去抑制，这表明仅占据操纵子位点不足以引起抑制。将两个操纵子转换为 lac 操纵子可在 Lac 阻遏蛋白存在的情况下恢复正常抑制。我们认为正常的抑制需要操纵子结合的抑制分子之间的相互作用；这会生成一个 DNA 环，它是高阶结构的一部分。 RNA 聚合酶和环 AMP 受体蛋白存在于该复合物中，但由于高级结构而无法启动转录。这种更高阶的DNA.sbd.多蛋白复合物可能出现在由调节蛋白从远端位点控制的多种遗传调节系统中。
Two operators, spatially separated from each other and from the promoters, repress the gal operon when bound to Gal repressor. Conversion of either gal operator to a lac operator results in derepression, although both Gal and Lac repressors are present, suggesting that mere occupation of operator sites is not sufficient to cause repression. Conversion of both operators to lac operators restores normal repression in the presence of Lac repressor protein. We propose that normal repression requires interaction between operator-bound like repressor molecules; this generates a DNA loop, which is part of a higher order structure. RNa polymerase and cyclic AMP receptor protein are present in this complex but unable to initiate transcription because of the higher order structure. Such higher order DNA.sbd.multiprotein complexes could occur in a variety of genetic regulatory systems that are controlled from distal sites by regulatory proteins.