Sternberg P W, Stern M J, Clark I, Herskowitz I
Cell. 1987 Feb 27;48(4):567-77. doi: 10.1016/0092-8674(87)90235-2.
Transcription of the yeast HO gene requires five genes, SWI 1, 2, 3, 4, 5. We present evidence that some SWI products activate HO by antagonizing negative regulatory activities encoded by the SIN genes. sin- mutants (defining six genes) were identified because they express HO in the absence of particular SWI products. We argue that SWI5 activates HO by antagonizing SIN3 and that SWI4 activates HO by antagonizing SIN6. HO is expressed in sin3- daughter cells, hence we infer that the SIN3 product represses HO in wild-type daughter cells and that SWI5 and SIN3 are responsible for the cell-lineage-dependent expression of HO. HO is transcribed only when all types of repression are absent: in mother cells, where SWI5 antagonizes SIN3; in late G1, when SWI4 antagonizes SIN6; and in a or alpha cells, where a1-alpha 2 repression is absent.
酵母HO基因的转录需要五个基因，即SWI 1、2、3、4、5。我们提供的证据表明，一些SWI产物通过拮抗SIN基因编码的负调控活性来激活HO。鉴定出了sin-突变体（定义了六个基因），因为它们在没有特定SWI产物的情况下表达HO。我们认为SWI5通过拮抗SIN3来激活HO，而SWI4通过拮抗SIN6来激活HO。HO在sin3-子细胞中表达，因此我们推断SIN3产物在野生型子细胞中抑制HO，并且SWI5和SIN3负责HO的细胞谱系依赖性表达。只有当所有类型的抑制都不存在时，HO才会转录：在母细胞中，SWI5拮抗SIN3；在G1晚期，SWI4拮抗SIN6；在a或α细胞中，不存在a1-α2抑制。
