Smith R L, Johnson A D
Dept of Biochemistry and Biophysics, University of California San Francisco, Box 0414, San Francisco, CA 94143, USA.
Trends Biochem Sci. 2000 Jul;25(7):325-30. doi: 10.1016/s0968-0004(00)01592-9.
The Ssn6-Tup1 repressor forms one of the largest and most important gene-regulatory circuits in budding yeast. This circuit, which appears conserved in flies, worms and mammals, exemplifies how a 'global' repressor (i.e. a repressor that regulates many genes in the cell) can be highly selective in the genes it represses. It also explains how, given the appropriate signal, specific subsets of these genes can be derepressed. Ssn6-Tup1 seems especially robust, bringing about a high level of repression irrespective of its precise placement on DNA or of specific features of the DNA control regions of its target genes. This high degree of repression probably results from several distinct mechanisms acting together.
Ssn6-Tup1阻遏物构成了芽殖酵母中最大且最重要的基因调控回路之一。该回路在果蝇、线虫和哺乳动物中似乎是保守的，它例证了一个“全局”阻遏物（即调控细胞中许多基因的阻遏物）如何能够在其所抑制的基因中具有高度选择性。它还解释了在给定适当信号的情况下，这些基因的特定子集如何能够被解除抑制。Ssn6-Tup1似乎特别强大，无论其在DNA上的精确位置或其靶基因的DNA控制区域的特定特征如何，都能带来高水平的抑制。这种高度的抑制可能是由几种不同的机制共同作用导致的。
