Analysis of viral gene functions by means of early temperature-sensitive mutants of human cytomegalovirus.

Fifteen ts mutants of CMV, which are unable to form normal plaques at 39 degrees C on HEL cells but do form plaques at 34 degrees C, have been isolated following mutagenesis by ultraviolet light. Five mutants defective in viral DNA synthesis at 39 degrees C were divided into two different complementation groups and examined for various phenotypic characteristics.