Role of σ-factor (orf21) in clavulanic acid production in Streptomyces clavuligerus NRRL3585.
A putative sigma factor gene, orf21, was disrupted or overexpressed in the wild-type clavulanic acid (CA) producer Streptomyces clavuligerus NRRL3585 and characterized. An orf21 mutant (Streptomyces clavuligerus HN14) of S. clavuligerus was obtained by insertional inactivation via double-crossover. Although there was little reduction of sporulation in the mutant, the growth pattern was similar between mutant and wild-type. The production was reduced by 10-15% in S. clavuligerus HN14 compared to that in wild-type. Overexpression of orf21 in wild-type cells caused hyperproduction of spores on solid medium and increased clavulanic acid production by 1.43-fold. The overexpression of orf21 in wild-type S. clavuligerus stimulated the expression of the early clavulanic acid genes, ceas2 and cas2, and the regulatory gene, ccaR, as demonstrated by RT-PCR. The elevation of the ceas2, cas2 and ccaR transcripts was consistent with the enhanced production of clavulanic acid.
Jnawali
Hum Nath
HN
Institute of Biomolecule Reconstruction (iBR), Department of Pharmaceutical Engineering, SunMoon University, # 100, Asansi, Chungnam 336-708, Republic of Korea.
Liou
Kwangkyoung
K
Sohng
Jae Kyung
JK
D019818:Clavulanic Acid / Q000096:biosynthesis*; D003470:Culture Media / Q000737:chemistry; D020869:Gene Expression Profiling; D055786:Gene Knockout Techniques; D016254:Mutagenesis, Insertional; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism*; D013171:Spores, Bacterial / Q000254:growth & development; D013302:Streptomyces / Q000166:cytology / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*
D003470:Culture Media; D012808:Sigma Factor; D019818:Clavulanic Acid