Evolution of sequence recognition by restriction-modification enzymes: Selective pressure for specificity decrease

Akito Chinen, Yasuhiro Naito, Naofumi Handa, Ichizo Kobayashi

研究成果: Article

20 引用 (Scopus)


Several type II restriction-modification (RM) gene complexes kill host bacterial cells that have lost them, through attack on the chromosomal recognition sites of these cells. Two RM gene complexes recognizing the same sequence cannot simultaneously enjoy such stabilization through postsegregational host killing, because one will defend chromosomal sites from attack by the other. In the present work, we analyzed intrahost competition between two RM gene complexes when the recognition sequence of one was included in that of the other. When the EcoRII gene complex, recognizing 5'-CCWGG (W = A, T), is lost from the host, the SsoII gene complex, which recognizes 5'-CCNGG (N = A, T, G, C), will prevent host death by protecting CCWGG sites on the chromosome. However, when the SsoII (CCNGG) gene complex is lost, the EcoRII (CCWGG) gene complex will be unable to prevent host death through attack by SsoII on 5'-CCSGG (S = C, G) sites. These predictions were verified in our experiments, in which we analyzed plasmid maintenance, cell growth, cell shape, and chromosomal DNA. Our results demonstrate the presence of selective pressure for decrease in the specificity of recognition sequence of RM systems in the absence of invading DNA.

ジャーナルMolecular Biology and Evolution
出版物ステータスPublished - 2000 1 1


ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Molecular Biology
  • Genetics