Noyer-Weidner M, Diaz R, Reiners L
Mol Gen Genet. 1986 Dec;205(3):469-75. doi: 10.1007/BF00338084.
Several chimeric pBR322/328 derivatives containing genes for cytosine-specific DNA methyltransferases (Mtases) can be transformed into the Escherichia coli K12/E. coli B hybrid strains HB101 and RR1 but not into other commonly used E. coli K12 strains. In vitro methylation of cytosine residues in pBR328 and other unrelated plasmids also reduces their potential to transform such methylation sensitive strains, albeit to a lesser degree than observed with plasmids containing Mtase genes. The extent of reduced transformability depends on the target specificity of the enzyme used for in vitro modification. The role of a host function in the discrimination against methylated plasmids was verified by the isolation of K12 mutants which tolerate cytosine methylated DNA. The mutations map in the vicinity of the serB locus. This and other data indicate that the host rglB function is involved in the discrimination against modified DNA.
几种含有胞嘧啶特异性DNA甲基转移酶（Mtases）基因的嵌合pBR322/328衍生物可转化到大肠杆菌K12/大肠杆菌B杂交菌株HB101和RR1中，但不能转化到其他常用的大肠杆菌K12菌株中。pBR328和其他无关质粒中胞嘧啶残基的体外甲基化也会降低它们转化此类甲基化敏感菌株的潜力，尽管程度低于含有Mtase基因的质粒。转化能力降低的程度取决于用于体外修饰的酶的靶标特异性。通过分离耐受胞嘧啶甲基化DNA的K12突变体，验证了宿主功能在区分甲基化质粒中的作用。这些突变位于serB基因座附近。这一结果和其他数据表明，宿主rglB功能参与了对修饰DNA的区分。
