Systematic sequencing of the 283 kb 210°-232° region of the Bacillus subtilis genome containing the skin element and many sporulation genes

As part of the Bacillus subtilis genome sequencing project, we have determined a 283 kb contiguous sequence from 210° to 232° of the B. subtilis genome. This region contains the 48 kb skin element which is excised during sporulation by a site-specific recombinase. In this region, 310 complete ORFs and one tRNA gene were identified: 66 ORFs have been sequenced and characterized previously by other workers, e.g. acc, ans, bfm, blt, bmr, comE, comG, dnaK, rpoD and sin operons; cwlA, gpr and lysA genes; many sporulation genes and operons, spo0A, spoIIA, spoIIM, spoIIP, spoIIIA, spoIIIC, spoIVB, spoIVCA, spoIVCB and spoVA, etc. The products of 84 ORFs were found to display significant similarity to proteins with known function in data banks, e.g., proteins involved in nucleotide metabolism, lipid biosynthesis, amino acid transport (ABC transporter), phosphate-specific transport, the glycine cleavage system, the two-component regulatory system, cell wall autolysis, ferric uptake and sporulation. However, the functions of more than half of the ORFs (52%, 160 ORFs) are still unknown. In the skin element containing 60 ORFs, 32 ORFs (53%) encode proteins which have significant homology to gene products of the B. subtilis temperate phage ∅105 and/or the defective phage PBSX.