Mutator mutations in bacteriophage T4 gene 42 (dHMC hydroxymethylase)

Genetics. 1977 Jul;86(3):501-11. doi: 10.1093/genetics/86.3.501.


Temperature-sensitive mutations of bacteriophage T4 gene 42 produce diverse effects upon spontaneous mutation rate. G:C vector A:T transition rates are increased, often strongly; frameshift mutation rates are weakly increased; A:T vector G:C transition rates (and perhaps also A:T vector Py:Pu transversion rates) are decreased; and one G:C vector Py:Pu transversion rate is also decreased. These results, together with certain interactions between gene-42 mutator effects and both base analogue mutagenesis and the viral error-prone repair system, suggest that the dHMC hydroxymethylase coded by gene 42 affects mutation rates in a more complex manner than by the simple regulation of the concentration of the DNA precursor dHMCTP.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Base Sequence
  • Chromosome Mapping
  • Coliphages / enzymology*
  • Cytosine
  • DNA Replication
  • DNA, Viral
  • Gene Frequency
  • Genes*
  • Models, Biological
  • Mutation*
  • Temperature
  • Transferases*


  • DNA, Viral
  • Cytosine
  • Transferases