Enhanced heterologous production of desosaminyl macrolides and their hydroxylated derivatives by overexpression of the pikD regulatory gene in Streptomyces venezuelae.
To elevate the production level of heterologous polyketide in Streptomyces venezuelae, an additional copy of the positive regulatory gene pikD was introduced into the pikromycin (Pik) polyketide synthase (PKS) deletion mutant of S. venezuelae ATCC 15439 expressing tylosin PKS genes. The resulting mutant strain showed enhanced production of both tylactone (TL) and desosaminyl tylactone (DesTL) of 2.7- and 17.1-fold, respectively. The notable increase in DesTL production strongly suggested that PikD upregulates the expression of the desosamine (des) biosynthetic gene cluster. In addition, two hydroxylated forms of DesTL were newly detected from the extract of this mutant. These hydroxylated forms presumably resulted from a PikD-dependent increase in expression of the pikC gene that encodes P450 hydroxylase. Gene expression analysis by reverse transcriptase PCR and bioconversion experiments of 10-deoxymethynolide, narbonolide, and TL into the corresponding desosaminyl macrolides indicated that PikD is a positive regulator of the des and pikC genes, as well as the Pik PKS genes. These results demonstrate the role of PikD as a pathway-specific positive regulator of the entire Pik biosynthetic pathway and its usefulness in the development of a host-vector system for efficient heterologous production of desosaminyl macrolides and novel hydroxylated compounds.
Jung
Won Seok
WS
Division of Nano Sciences, Ewha Womans University, Seoul 120-750, South Korea. joonyoon@ewha.ac.kr
Jeong
Soon Jeong
SJ
Park
Sung Ryeol
SR
Choi
Cha Yong
CY
Park
Byoung Chul
BC
Park
Je Won
JW
Yoon
Yeo Joon
YJ
D000606:Amino Sugars / Q000096:biosynthesis* / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000096:biosynthesis / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D005809:Genes, Regulator; D018942:Macrolides; D013302:Streptomyces / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D000606:Amino Sugars; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D018942:Macrolides; C428122:PikD protein, Streptomyces venezuelae; D014157:Transcription Factors; C110125:desosamine