An unexpected role for the putative 4'-phosphopantetheinyl transferase-encoding gene nysF in the regulation of nystatin biosynthesis in Streptomyces noursei ATCC 11455.
The nysF gene encoding a putative 4'-phosphopantetheinyl transferase (PPTase) is located at the 5' border of the nystatin biosynthesis gene cluster in Streptomyces noursei. PPTases carry out post-translational modification of the acyl carrier protein domains on the polyketide synthases (PKS) required for their full functionality, and hence NysF was assumed to be involved in similar modification of the nystatin PKS. At the same time, DNA sequence analysis of the genomic region adjacent to the nysF gene revealed a gene cluster for a putative lantibiotic biosynthesis. This finding created some uncertainty regarding which gene cluster nysF functionally belongs to. To resolve this ambiguity, nysF was inactivated by both insertion of a kanamycin (Km) resistance marker into its coding region, and by in-frame deletion. Surprisingly, the nystatin production in both the nysF::Km(R) and DeltanysF mutants increased by ca. 60% compared to the wild-type, suggesting a negative role of nysF in the nystatin biosynthesis. The expression of xylE reporter gene under control of different promoters from the nystatin gene cluster in the DeltanysF mutant was studied. The data obtained clearly show enhanced expression of xylE from the promoters of several structural and regulatory genes in the DeltanysF mutant, implying that NysF negatively regulates the nystatin biosynthesis.
Department of Biotechnology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway.
Olga
O
Volokhan
Håvard
H
Sletta
Olga N
ON
Sekurova
Trond E
TE
Ellingsen
Sergey B
SB
Zotchev
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D009761:Nystatin / Q000096:biosynthesis*; D013302:Streptomyces / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D017855:Transferases (Other Substituted Phosphate Groups) / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
D001426:Bacterial Proteins; C082662:phosphopantetheinyl transferase; D009761:Nystatin; D017855:Transferases (Other Substituted Phosphate Groups)