Singh A, Manney T R
Genetics. 1974 Aug;77(4):661-70. doi: 10.1093/genetics/77.4.661.
A suppressor SUP101 of alleles trp5-67 and trp5-18 of the trp5 locus of Saccharomyces cerevisiae is described. The two suppressible mutations have been previously classified as missense. The suppression does not result from a physiological bypass of the tryptophan synthetase-catalyzed reaction, since the suppression is allele-specific. IU alleles trp5-70, tryp5-95, and trp5-102; IA alleles trp5-81, trp5-101, and trp5-103; and the ochre alleles trp5-33 and trp5-48 are not suppressed by SUP101. SUP101 does not suppress ochre alleles ade2-1, his5-2, arg4-17, lys1-1, amber alleles trp1-1, tyr7-1, or unclassified alleles at a number of other loci. These results indicate SUP101 is a missense suppressor. Growth on tryptophanless media is dependent upon gene dosage of both the suppressor and the suppressible alleles. Only the diploids homozygous both for the suppressor and suppressible alleles produce growth equivalent to growth of the haploids bearing a suppressible allele and the suppressor. Suppressor-bearing strains grow poorly even on tryptophan-supplemented media. In more than 100 asci analyzed partial growth inhibition on the complete medium always segregated with the suppressor.
本文描述了酿酒酵母色氨酸合成酶基因座trp5的等位基因trp5 - 67和trp5 - 18的一个抑制基因SUP101。这两个可被抑制的突变先前被归类为错义突变。这种抑制并非由色氨酸合成酶催化反应的生理旁路引起，因为这种抑制具有等位基因特异性。trp5 - 70、trp5 - 95和trp5 - 102等IU等位基因；trp5 - 81、trp5 - 101和trp5 - 103等IA等位基因；以及赭石型等位基因trp5 - 33和trp5 - 48均不能被SUP101抑制。SUP101也不能抑制赭石型等位基因ade2 - 1、his5 - 2、arg4 - 17、lys1 - 1，琥珀型等位基因trp1 - 1、tyr7 - 1，或其他多个基因座上未分类的等位基因。这些结果表明SUP101是一个错义抑制基因。在无色氨酸培养基上的生长取决于抑制基因和可被抑制等位基因的基因剂量。只有抑制基因和可被抑制等位基因均为纯合的二倍体才能产生与携带可被抑制等位基因和抑制基因的单倍体相当的生长。携带抑制基因的菌株即使在添加色氨酸的培养基上生长也很差。在分析的100多个子囊中，完全培养基上的部分生长抑制总是与抑制基因一起分离。
