Open AccessThe tripartite immunity system of phages P1 and P7
Author(s) -
Heinrich Jochen,
Velleman Mathias,
Schuster Heinz
Publication year - 1995
Publication title -
fems microbiology reviews
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.91
H-Index - 212
eISSN - 1574-6976
pISSN - 0168-6445
DOI - 10.1111/j.1574-6976.1995.tb00193.x
Subject(s) - prophage , biology , repressor , lytic cycle , gene , genetics , plasmid , lysogenic cycle , psychological repression , bacteriophage , gene expression , virus , escherichia coli
Prophages P1 and P7 exist as unit copy DNA plasmids in the bacterial cell. Maintenance of the prophage state requires the continuous expression of two repressors: (i) C1 is a protein which negatively regulates the expression of lytic genes including the C1 inactivator gene coi , and (ii) C4 is an antisense RNA which specifically inhibits the synthesis of an anti‐repressor Ant. In addition, C1 repression is strengthened by lxc encoding an auxiliary repressor protein. The repressors C1, C4 and Lxc are components of a tripartite immunity system of the two phages. Here, the mode of action of these regulatory components including their antagonists Coi and Ant is described.