Mutator and antimutator effects of the bacteriophage P1 hot gene product.
The Hot (homolog of theta) protein of bacteriophage P1 can substitute for the Escherichia coli DNA polymerase III theta subunit, as evidenced by its stabilizing effect on certain dnaQ mutants that carry an unstable polymerase III epsilon proofreading subunit (antimutator effect). Here, we show that Hot can also cause an increase in the mutability of various E. coli strains (mutator effect). The hot mutator effect differs from the one caused by the lack of theta. Experiments using chimeric theta/Hot proteins containing various domains of Hot and theta along with a series of point mutants show that both N- and C-terminal parts of each protein are important for stabilizing the epsilon subunit. In contrast, the N-terminal part of Hot appears uniquely responsible for its mutator activity.
Chikova
Anna K
AK
Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, P.O. Box 12233, Research Triangle Park, NC 27709, USA.
Schaaper
Roel M
RM
D017101:Bacteriophage P1 / Q000235:genetics* / Q000378:metabolism*; D004258:DNA Polymerase III / Q000235:genetics* / Q000378:metabolism*; D004259:DNA-Directed DNA Polymerase / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D015967:Gene Expression Regulation, Viral; D011994:Recombinant Proteins; D014764:Viral Proteins / Q000235:genetics* / Q000378:metabolism*
D029968:Escherichia coli Proteins; D011994:Recombinant Proteins; D014764:Viral Proteins; C500758:HOT protein, bacteriophage P1; C505238:holE protein, E coli; D004258:DNA Polymerase III; D004259:DNA-Directed DNA Polymerase