Second-site suppressors of a cold-sensitive external scaffolding protein of bacteriophage phi X174

Genetics. 1993 Aug;134(4):1003-11.


This report describes the isolation and characterization of second-site suppressors of a cold-sensitive (cs) external scaffolding protein, gpD, of bacteriophage phi X174. Seven genetically distinct suppressors were isolated. Six of them are located in gene F which encodes the major coat protein of the virus. The seventh is located in gene J which encodes the DNA-binding protein. A subset of the suppressors are trans-acting. These second-site suppressors do not exhibit allele specificity; they are able to suppress defects associated with a csD protein for which they were not selected. The initial characterization of the second-site suppressors and their locations within the major coat protein suggest that the mechanism of suppression may involve both structural and stoichiometric phenomena.

Publication types

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

MeSH terms

  • Alleles
  • Bacteriophage phi X 174 / genetics*
  • Cold Temperature
  • Genes, Viral
  • Genetic Complementation Test
  • Oligonucleotides
  • Suppression, Genetic*
  • Transcriptional Activation
  • Viral Proteins / genetics*


  • Oligonucleotides
  • Viral Proteins