Gardel C, Benson S, Hunt J, Michaelis S, Beckwith J
J Bacteriol. 1987 Mar;169(3):1286-90. doi: 10.1128/jb.169.3.1286-1290.1987.
New mutants of Escherichia coli altered in protein export were identified in phoA-lacZ and lamB-lacZ gene fusion strains by searching for mutants that showed an altered lactose phenotype. Several mutations mapped in a new gene, secD. These mutants were, in general, cold sensitive for growth, and the mutations led to an accumulation of precursor of exported proteins. The secD gene is closely linked to tsx on the E. coli chromosome, but separable from another gene proposed to be involved in export, ssaD, which maps nearby. A plasmid carrying secD+ was identified and used to show that the mutations are recessive. The secD gene may code for a component of the cellular export machinery.
通过寻找乳糖表型发生改变的突变体，在 phoA-lacZ 和 lamB-lacZ 基因融合菌株中鉴定出了大肠杆菌中蛋白质输出发生改变的新突变体。有几个突变定位在一个新基因 secD 中。这些突变体通常对生长温度敏感，并且这些突变导致输出蛋白前体的积累。secD 基因与大肠杆菌染色体上的 tsx 紧密连锁，但与另一个推测参与输出的基因 ssaD 是可分离的，ssaD 基因位于附近。一个携带 secD⁺ 的质粒被鉴定出来，并用于证明这些突变是隐性的。secD 基因可能编码细胞输出机制的一个组成部分。
