Cbmmunication Gamma - Hemolysin Genes in the Same Family with LukF and inkS Genes in Methici - n

7-hemolysin, consist of two protein component, i.e,, F and S fbr leukocidin and H7I and H7II fbr 7-hemolysin, We have reported the cloning and sequencing of the leukocidin genes lukS and inkF from MRSA No. 4,2'3) In a previous report4) we purified both H7I and Hvll components to hornogeneity from S. aureus, compared their properties with those of the F and S components of leukocidin, and suggested that the leukocidin F component is identical with 7-hemolysin H7I. In this report, by sequencing the DNA, we demonstrate that lukF acts as a common gene for the two toxins, leukocidin and v-hemolysin and the specific activity of leukocidin and 7-hemolysin are set by the gene product of lukS or hig2, i.e., the S or H7II component. The 72% homology of the N-terrninal 58-residue amino acid sequences from S and H7II indicatcd their similar DNA sequences, Therefbre, we hybridized Hindlll-digested chromosomal DNA of MRSA No, 4 and S. aureus 5R Smith, which is a known producer of 7-hemolysin,5} with a