Figure 6

Polyketide synthesis operon. An operon structure for a series of polyketide synthesis genes from pksB to pksR which begins with transcriptional regulator pksA and ends with hydroxylase of polyketide pksS is completely deleted in B. subtilis natto BEST195. Link plot of the alignment between a region including the polyketide synthesis operon in Marburg 168 and the corresponding region in BEST195 is displayed. The alignment was calculated using Murasaki, a multiple genome comparison program [16]. Each line between them indicates an anchor, which is a short well-conserved subsequence. Four PCR primers, A: 5'-AGAAAACAAATTGCAGAAGCAAC-3', B: 5'-GCATGTTGTTAAAGCACATAGCA-3', C: 5'-GATTGCATATGAAGTCACTCGC-3', and D: 5'-TACTCTACTCAGGTTGAGTGGGC-3' are indicated by horizontal short arrows. These primers are designed to amplify both ends of polyketide synthesis operon in 168. The pair of primers A, B and the pair C, D produced the predicted 3.14-kb and 3.10-kb fragments from 168. In contrast, only the pair A, D produced a predicted 1.62-kb fragment from BEST195 (data not shown).