Boeke J D, Styles C A, Fink G R
Mol Cell Biol. 1986 Nov;6(11):3575-81. doi: 10.1128/mcb.6.11.3575-3581.1986.
Mutations in the Saccharomyces cerevisiae SPT3 gene have dramatic effects on the expression of Ty elements and genes adjacent to the element. The SPT3 gene is essential for Ty transposition, because transposition of chromosomal Ty elements ceased when the SPT3 gene was replaced with the frameshift mutation spt3-101. Presumably, the elimination of transposition was due to the effect of the SPT3 gene product on Ty transcription; the transcripts of chromosomal Ty elements were largely abolished in the spt3-101 strain (F. Winston, K. J. Durbin, and G. R. Fink, Cell 39:675-682, 1984). Ty transcription in an spt3-101 strain could be reestablished by introduction of the pGTyH3 plasmid, in which transcription of the Ty element TyH3 is under the control of the GAL1 promoter; these plasmid-derived Ty transcripts were SPT3-independent. Ty transposition resumed after galactose induction in spt3-101 strains containing the pGTyH3 plasmid. In spt3 mutants nearly all of the resulting transposition events derived from pGTyH3 plasmids and not from chromosomal elements.
酿酒酵母SPT3基因的突变对Ty元件及该元件附近基因的表达有显著影响。SPT3基因对于Ty转座至关重要，因为当SPT3基因被移码突变spt3 - 101取代时，染色体Ty元件的转座就会停止。据推测，转座的消除是由于SPT3基因产物对Ty转录的影响；在spt3 - 101菌株中，染色体Ty元件的转录本基本被消除（F. Winston、K. J. Durbin和G. R. Fink，《细胞》39:675 - 682，1984）。通过引入pGTyH3质粒可以在spt3 - 101菌株中重新建立Ty转录，其中Ty元件TyH3的转录受GAL1启动子控制；这些质粒衍生的Ty转录本不依赖SPT3。在含有pGTyH3质粒的spt3 - 101菌株中，半乳糖诱导后Ty转座恢复。在spt3突变体中，几乎所有产生的转座事件都源自pGTyH3质粒而非染色体元件。
