Babudri N, Monti-Bragadin C
Mol Gen Genet. 1977 Oct 24;155(3):287-90. doi: 10.1007/BF00272807.
N and I group plasmids, which increase methylmethane sulfonate (MMS) mutagenesis in lexA+ strains of E. coli WP2 may be divided into two classes: those restoring part of the mutability of lexA- stains (class I) and those leaving lexA- strains non-mutable (class II). Almost complete restoration of MMS mutability is obtained by class I plasmids in a partially suppressed lexA rnm strain, while clase II plasmids cause far fewer MMS revertants in this strain than in lexA+. A pair of class I and II plasmids in lexA- shows a synergistic effect on mutability. These two classes do not coincide with plasmid division into incompatibility groups.
N和I组质粒可增加大肠杆菌WP2的lexA⁺菌株中甲基磺酸甲酯（MMS）诱变作用，可分为两类：一类可恢复lexA⁻菌株部分诱变能力（I类），另一类使lexA⁻菌株不发生诱变（II类）。I类质粒在部分抑制的lexA rnm菌株中几乎可完全恢复MMS诱变能力，而II类质粒在此菌株中引起的MMS回复突变体比在lexA⁺菌株中少得多。lexA⁻中的一对I类和II类质粒对诱变作用具有协同效应。这两类质粒与按不相容群划分的质粒不同。
