Bacteriophage T4 genes encode many essential
enzymes for DNA replication. Mutations in these genes inhibit replication of the phage genome during infection
(Epstein et al, 1963). Some genes that would typically be nonessential for phage growth on wild type E. coli bacteria
hosts can be studied on isolated mutant E. coli strains for which those genes are essential. Genetic mutations
within these bacteria inactivate specific host activities that duplicate the activities of phage gene products.
Growth of mutant phage strains will therefore be restricted on bacteria with mutations in similar genes (Coppo
et al., 1973). We have identified an E. coli mutant strain which is unable to support the growth of T4 strains defective in a gene we call dexA. It is the purpose of this research to isolate, identify and map the amber and temperature sensitive mutations of dexA. The techniques to be used include mutagenesis, spot complementation testing, phage crosses, PCR and plasmid DNA isolation. If time permits, ultraviolet light irradiation and cloning techniques will also be used.