HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: mic.0.028639-0v1 155/6/1819    most recent Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Google Scholar Articles by Li, R. Articles by Tan, H. PubMed PubMed Citation Articles by Li, R. Articles by Tan, H. Agricola Articles by Li, R. Articles by Tan, H.

polR, a pathway-specific transcriptional regulatory gene, positively controls polyoxin biosynthesis in Streptomyces cacaoi subsp. asoensis

Rui Li^1,

Zhoujie Xie^1,

¹ State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
² Laboratory of Microbial Metabolism and School of Life Science and Biotechnology, Shanghai Jiaotong University, Shanghai 200030, China

The polyoxin (POL) biosynthetic gene cluster (pol) was recently cloned from Streptomyces cacaoi subsp. asoensis. A 3.3 kb DNA fragment carrying an obvious open reading frame (polR), whose deduced product shows sequence similarity to SanG of Streptomyces ansochromogenes and PimR of Streptomyces natalensis, was revealed within the pol gene cluster. Disruption of polR abolished POL production, which could be complemented by the integration of a single copy of polR into the chromosome of the non-producing mutant. The introduction of an extra copy of polR in the wild-type strain resulted in increased production of POLs. The transcription start point (tsp) of polR was determined by S1 mapping. Reverse transcriptase PCR experiments showed that PolR is required for the transcription of 18 structural genes in the pol gene cluster. Furthermore, we showed that polC and polB, the respective first genes of two putative operons (polC–polQ2 and polA–polB) consisting of 16 and 2 of these 18 genes, have similar promoter structures. Gel retardation assays indicated that PolR has specific DNA-binding activity for the promoter regions of polC and polB. Our data suggest that PolR acts in a positive manner to regulate POL production by activating the transcription of at least two putative operons in the pol gene cluster.

Correspondence
Huarong Tan
tanhr{at}sun.im.ac.cn
Zixin Deng
zxdeng{at}sjtu.edu.cn

These authors contributed equally to this work.

The GenBank/EMBL/DDBJ accession number for the sequence reported in this paper is EU158805.