Wandersman C, Moreno F, Schwartz M
J Bacteriol. 1980 Sep;143(3):1374-83. doi: 10.1128/jb.143.3.1374-1383.1980.
tpo mutations, located at 74 min on the genetic map, rendered Escherichia coli K-12 resistant to TP1, a phage which can use either the OmpF protein or the LamB protein as its receptor. tpo mutants synthesized decreased amounts of OmpF and LamB proteins but increased amounts of the OmpC product, another outer membrane protein. The effect of the tpo mutations in lam B gene expression was transcriptional. It is one facet of the following effect on the maltose regulon: strong decreases in the syntheses of the LamB protein and the periplasmic MalE protein occurred when the regulon was uninduced; a lesser decrease occurred in the syntheses of the LamB protein the MalE protein, and the cytoplasmic MalQ protein (amylomaltase) when the regulon was induced. The tpo mutants were found to be phenotypically identical to the perA mutant recently described by Wanner et al. (J. Bacteriol. 140:229--239, 1979) and to some of the ompB mutants described by Verhoef et al. (Mol. Gen. Genet. 169:137--146, 1979). Mapping and complementation analysis suggested that these three types of mutations belong to the same cistron. Our results bring to at least four the number of clearly distinct phenotypes which can result from mutations at, or close to, ompB, a locus which appears increasingly complex.
tpo突变位于遗传图谱的74分钟处，使大肠杆菌K-12对TP1产生抗性，TP1是一种噬菌体，它可以使用OmpF蛋白或LamB蛋白作为其受体。tpo突变体合成的OmpF和LamB蛋白量减少，但另一种外膜蛋白OmpC产物的量增加。tpo突变对lam B基因表达的影响是转录性的。这是对麦芽糖调节子以下影响的一个方面：当调节子未被诱导时，LamB蛋白和周质MalE蛋白的合成强烈减少；当调节子被诱导时，LamB蛋白、MalE蛋白和细胞质MalQ蛋白（淀粉麦芽糖酶）的合成减少程度较小。发现tpo突变体在表型上与Wanner等人（《细菌学杂志》140:229-239，1979年）最近描述的perA突变体以及Verhoef等人（《分子遗传学与普通遗传学》169:137-146，1979年）描述的一些ompB突变体相同。定位和互补分析表明，这三种类型的突变属于同一个顺反子。我们的结果使可能由ompB位点或其附近的突变产生的明显不同表型的数量至少增加到四个，ompB位点似乎越来越复杂。
