Lambda Transducing Phage and Clones Carrying Genes of the cysJIHDC Gene Cluster of Escherichia coli K 12

SUMMARY: DNA from each of two specialized transducing α phage, γdcysJIHD and γcysJ, has been analysed by heteroduplex mapping. The segment of the Escherichia coli chromosome carried by γdcysJlHD was shown to be large, approximately 18 kb in length, and to replace a large length of γDNA, approximately 11 kb, which includes the genes for integration and recombination. Thus γdcysJIHD is a bio-type transducing phage. γcysJ was shown to have lost very little γDNA and to carry about 8 kb of bacterial DNA. Sites for several restriction endonucleases were mapped in the DNA from each phage and cloning experiments located some of the genes of the cluster in relation to the restriction map. Cysteine regulation of the cloned cysJ and cysD genes was shown as well as cysteine regulation of P-galactosidase in some constructs. The direction of transcription of the cysD gene was established, and from physical evidence the size of the ‘silent section’ between the cysH and cysD genes was estimated to be at least 11 kb.