Almouzni G, Wolffe A P
Laboratory of Molecular Embryology, National Institute of Child Health and Human Development, Bethesda, Maryland 20892.
Genes Dev. 1993 Oct;7(10):2033-47. doi: 10.1101/gad.7.10.2033.
The chromatin assembly process coupled to DNA synthesis in the Xenopus oocyte nucleus is significantly more repressive toward basal transcription than chromatin assembly on duplex DNA. We show that chromatin assembly concurrent with DNA synthesis over the promoter region itself is causal for repression. However, the trans-activator Gal4-VP16 both relieves repression and activates transcription regardless of the chromatin assembly pathway. This activation is independent of whether Gal4-VP16 addition occurs before or after chromatin assembly. We propose that replication-coupled chromatin assembly represents a general mechanism to direct the efficient repression of basal transcription. However transcription induction by a specific activator, Gal4-VP16, occurs independent of this chromatin-mediated repression.
非洲爪蟾卵母细胞核中与DNA合成偶联的染色质组装过程，相较于双链DNA上的染色质组装，对基础转录的抑制作用要强得多。我们发现，在启动子区域本身与DNA合成同时发生的染色质组装是造成抑制的原因。然而，反式激活因子Gal4-VP16无论染色质组装途径如何，都能解除抑制并激活转录。这种激活与Gal4-VP16的添加是在染色质组装之前还是之后发生无关。我们提出，复制偶联的染色质组装代表了一种指导有效抑制基础转录的普遍机制。然而，由特定激活因子Gal4-VP16介导的转录诱导独立于这种染色质介导的抑制作用而发生。
