Rodicio R
Technische Hochschule Darmstadt, Institut für Mikrobiologie, Federal Republic of Germany.
Curr Genet. 1986;11(3):235-41. doi: 10.1007/BF00420612.
Two maltase constitutive alleles MAL1-1c and MAL1-2c were obtained as revertants from a defective mall-1 mutant allele not promoting maltose fermentation. Classical genetical analysis showed that the mutations were linked or allelic to the MAL1 locus. Dominance relations were established by testing alpha-glucosidase activities in diploids containing various allele combinations. The maltose regulatory genes belonging to the MAL1, MAL1-1c and MAL1-2c alleles were cloned. Differences in restriction sites were found between the wild type MAL1 and the derived MAL1-constitutive alleles. The MAL1 regulatory gene was located in a 1.15 kb EcoRI fragment (Rodicio and Zimmermann 1985a, b). An EcoRI fragment of this size was found in plasmids containing the MAL1 regulatory wild type allele but was absent from plasmids carrying the constitutive alleles. The genomic organization of the MAL loci in the constitutive mutants was confirmed by Southern analysis. Various fragments containing sequences of the different MAL1 alleles were used to probe genomic digests of MAL1, MAL1-1c and MAL1-2c strains. The results obtained support the conclusion that the constitutive mutations had arisen by a rearrangement between the original mal1-1 mutant allele and sequences with different location in the genome.
从一个不能促进麦芽糖发酵的缺陷型mall - 1突变等位基因获得了两个麦芽糖酶组成型等位基因MAL1 - 1c和MAL1 - 2c作为回复突变体。经典遗传学分析表明，这些突变与MAL1位点连锁或等位。通过检测含有各种等位基因组合的二倍体中的α - 葡萄糖苷酶活性，确定了显性关系。克隆了属于MAL1、MAL1 - 1c和MAL1 - 2c等位基因的麦芽糖调节基因。发现野生型MAL1与衍生的MAL1组成型等位基因之间存在限制性位点差异。MAL1调节基因位于一个1.15 kb的EcoRI片段中（Rodicio和Zimmermann，1985a，b）。在含有MAL1调节野生型等位基因的质粒中发现了这种大小的EcoRI片段，但携带组成型等位基因的质粒中没有。通过Southern分析证实了组成型突变体中MAL位点的基因组组织。用含有不同MAL1等位基因序列的各种片段探测MAL1、MAL1 - 1c和MAL1 - 2c菌株的基因组消化产物。获得的结果支持这样的结论：组成型突变是由原始mal1 - 1突变等位基因与基因组中不同位置的序列之间的重排产生的。
