REGULATION OF THE ESCHERICHIA-COLI SHEA GENE AND CHARACTERIZATION OF ITS ENCODED HEMOLYTIC-ACTIVITY

Escherichia coli K-12 carries the cryptic hemolysin gene sheA which is under the control of positive and negative transcriptional regulators . The objectives of the present study were to further analyze the regu lation of the sheA gene in E. coli, to compare the sheA genes from E. coli K-12 and a pathogenic E. coli strain, and to characterize the She A hemolytic activity. Northern blot analysis demonstrated that the tra nscriptional regulator SlyA activates the E. coli K-12 sheA gene. The main transcriptional start site of the sheA gene was 56 nucleotides up stream from the start codon as determined by primer extension analysis . The sheA genes from E. coli K-12 and a pathogenic E. coli strain wer e identical. SheA hemolytic activity was cell associated and Ca2+ inde pendent. (C) 1998 Federation of European Microbiological Societies. Pu blished by Elsevier Science B.V. All rights reserved.