Fig. 4: knm BGC in comparison with bal and ris BGCs and the operon structure of knm.

a knm consists of 41 ORFs (resembling bal and ris BGCs, but lacking genes for methyltransferases). It is organized into 8 operons and 6 monogenic transcriptional units, according to (b) the results of semi-quantitative RT-PCR analysis showing the expression (or absence thereof) of all intergenic regions (35, except for the ones where neighboring genes lie on opposite strands and cannot be co-expressed) within knm. RNA was extracted from Kmc producing culture cultivated in R5 medium for 96 h, processed into cDNA, and used as a template for PCRs; chromosome DNA (gDNA) served as a positive control for each reaction, while non-treated RNA as a negative control; electrophoregrams represent the average results of three independent experiments.