Shore D, Stillman D J, Brand A H, Nasmyth K A
MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, UK.
EMBO J. 1987 Feb;6(2):461-7. doi: 10.1002/j.1460-2075.1987.tb04776.x.
The 'silent' yeast mating-type loci (HML and HMR) are repressed by sequences (HMLE and HMRE) located over 1 kb from their promoters which have properties opposite those of enhancers, and are called 'silencers'. Both silencers contain autonomously replicating sequences (ARS). Silencer activity requires four trans-acting genes called SIR (silent information regulator). We have identified two DNA binding factors , SBF-B and SBF-E, which bind to known regulatory elements at HMRE. SBF-B binds to a region involved in both the silencer and ARS functions of HMRE, but doesn not bind to HMLE. This factor also binds to the unlinked ARS1 element. SBF-E recognizes a sequence found at both silencers. These results suggest that the two silencers may be composed of different combinations of regulatory elements at least one of which is common to both. Neither factor appears to be a SIR gene product. Hence the SIR proteins may not directly interact with the silencer control sites.
“沉默”的酵母交配型基因座（HML和HMR）受到位于其启动子上游超过1 kb处的序列（HMLE和HMRE）的抑制，这些序列具有与增强子相反的特性，被称为“沉默子”。两个沉默子都包含自主复制序列（ARS）。沉默子活性需要四个称为SIR（沉默信息调节因子）的反式作用基因。我们鉴定出了两种DNA结合因子，SBF-B和SBF-E，它们与HMRE处已知的调控元件结合。SBF-B与参与HMRE沉默子和ARS功能的区域结合，但不与HML结合。该因子也与未连锁的ARS1元件结合。SBF-E识别在两个沉默子中都存在的一个序列。这些结果表明，两个沉默子可能由不同的调控元件组合组成，其中至少有一个是两者共有的。这两种因子似乎都不是SIR基因产物。因此，SIR蛋白可能不会直接与沉默子控制位点相互作用。
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