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I-Ceul recognition sites in the rrn operons of the Bacillus subtilis 168 chromosome: inherent landmarks for genome analysis

1995; Microbiology Society; Volume: 141; Issue: 8 Linguagem: Inglês

10.1099/13500872-141-8-1937

1465-2080

Tsutomu Toda, Mitsuhiro Itaya,

Genomics and Phylogenetic Studies

The Bacillus subtilis 168 circular chromosome yielded ten fragments on I- Ceu i endonuclease digestion. I- Ceu l recognizes a 26 bp sequence that is located within the gene encoding the 235 subunit of the rRNA in Chlamydomonas eugametos, Escherichia coli and Salmonella typhimurium. The precise locations of the I- Ceu l sites of the B. subtilis chromosome were determined on a Notl-Sfi l physical map by (i) double digestion analyses with I- Ceu l and Sfi l, (ii)comparison of mutant strains lacking a specific rrn operon, (iii)using an I- Ceu l linking clone and (iv) analysis of nucleotide sequence data of some rrn operons. In conclusion, all the I- Ceu l sites were located within the B. subtilis rrn operons and the I- Ceu l sites were conserved in all the B. subtilis 168 derivatives tested. Thus, variations in size of the I- Ceu l fragments must be due to genome alterations. A B. subtilis 168 strain was investigated with I- Ceu l. We demonstrated that the aberrant structure was the outcome of the inversion of an ~ 1700 kb DNA segment.