GENE ARRANGEMENT IN THE UPSTREAM REGION OF CLOSTRIDIUM-BOTULINUM TYPE-E AND CLOSTRIDIUM-BUTYRICUM BL6340 PROGENITOR TOXIN GENES IS DIFFERENT FROM THAT OF OTHER TYPES

The cluster of genes encoding the botulinum progenitor toxin and the u pstream region including p21 and p47 were divided into three different gene arrangements (class I-III). To determine the gene similarity of the type E neurotoxin (BoNT/E) complex to other types, the gene organi zation in the upstream region of the nontoxic-nonhemagglutinin gene (n tnh) was investigated in chromosomal DNA from Clostridium botulinum ty pe E strain Iwanai and C. butyricum strain BL6340. The gene cluster of type E progenitor toxin (Iwanai and BL6340) was similar to those of t ype F and type A (from infant botulism in Japan), but not to those of types A, B, and C. Though genes for the hemagglutinin component and P2 1 were not discovered, genes encoding P47, NTNH, and BoNT were found i n type E strain Iwanai and C. butyricum strain BL6340. However, the ge nes of ORF-X-1 (435 bp) and ORF-X-2 (partially sequenced) were present just upstream of that of P47. The orientation of these genes was in i nverted direction to that of p47. The gene cluster of type E progenito r toxin (Iwanai and BL6340) is, therefore, a specific arrangement (cla ss IV) among the genes encoding components of the BoNT complex. (C) 19 98 Federation of European Microbiological Societies. Published by Else vier Science B.V.