Beutin L, Achtman M
J Bacteriol. 1979 Sep;139(3):730-7. doi: 10.1128/jb.139.3.730-737.1979.
Twelve mutants of Escherichia coli K-12 have been isolated which carry chromosomal mutations that exhibit pleiotropic effects on the expression of F factor tra cistrons. F pilus synthesis, deoxyribonucleic acid transfer, and surface exclusion are all inhibited. Six of the mutants carry sfrA mutations, and six carry sfrB mutations. sfrA and sfrB are cistrons mapping near thr and metE, respectively. Several F-like plasmids are dependent on sfrA and on sfrB for expression of tra cistrons. Plasmids of incompatibility groups C and S are only dependent on sfrB,and other conjugative plasmids are dependent on neither. sfrB mutations also result in changes in certain cell envelope properties, including change sensitivity to certain bacteriophages which use lipopolysaccharide as a receptor, synthesis of nonfunctional flagella, and altered sensitivity to antibiotics.
已分离出12株大肠杆菌K-12突变体，它们携带的染色体突变对F因子tra顺反子的表达具有多效性影响。F菌毛合成、脱氧核糖核酸转移和表面排斥均受到抑制。其中6个突变体携带sfrA突变，6个携带sfrB突变。sfrA和sfrB分别是位于thr和metE附近的顺反子。几种F样质粒的tra顺反子表达依赖于sfrA和sfrB。不相容群C和S的质粒仅依赖于sfrB，而其他接合性质粒则两者均不依赖。sfrB突变还会导致某些细胞包膜特性的变化，包括对某些以脂多糖为受体的噬菌体的敏感性改变、无功能鞭毛的合成以及对抗生素的敏感性改变。
