1A-08 Suicidal defense against an epigenetic system： a role for a Type IV methyl-dependent restriction enzyme

Attack on the host cell chromosome by restriction enzymes is a subject of various biological interactions. When several Type II restriction-modification gene complexes enter a new host cell, they try to avoid chromosome breakage and cell killing by expressing the modification enzyme first. Once they...

Full description

Saved in:
Bibliographic Details
Published inGenes & Genetic Systems Vol. 81; no. 6; p. 408
Main Authors FUKUDA Eri, KOBAYASHI Ichizo
Format Journal Article
LanguageJapanese
Published The Genetics Society of Japan 2006
Online AccessGet full text

Cover

More Information
Summary:Attack on the host cell chromosome by restriction enzymes is a subject of various biological interactions. When several Type II restriction-modification gene complexes enter a new host cell, they try to avoid chromosome breakage and cell killing by expressing the modification enzyme first. Once they establish themselves, they attack the host chromosome when their presence is threatened. Through this post-segregational killing strategy, they force their maintenance on the host. On the other hand, Escherichia coli cells employ a Type IV restriction enzyme McrBC, which recognizes methylated DNAs and cleaves DNA between two of these recognition sites. We hypothesize that McrBC serves for suicidal defense against invasion of specific DNA methylation systems. In this work, we analyze host attack by McrBC. We demonstrate McrBC-mediated abortion of establishment of a modification enzyme gene in E. coli. We also demonstrate McrBC-dependent cell death and chromosomal DNA degradation following genome methylation by RM systems. These results support our hypothesis. To our knowledge, this represents the first example of direct suicidal defense against an epigenetic system.
ISSN:1341-7568