Spontaneous temperature-sensitive mutations in bacteriophage T7.

Attempts to recover temperature-sensitive mutations affecting genes 13 and 14 (virion proteins) in bacteriophage T7 by analysis of amber revertants were confounded by the frequent occurrence of spontaneous temperature-sensitive mutations in other genes. These incidental temperature-sensitive mutations are physically distinct from but may be functionally related to genes 13 and 14, as shown by complementation and recombination studies. The possibility that these incidental temperature-sensitive mutations represent secondary-site suppressors of the pseudonormal suppressed amber products is discussed.