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Pleiotropic regulatory genes bldA, adpA and absB are implicated in production of phosphoglycolipid antibiotic moenomycin.

Makitrynskyy R, Ostash B, Tsypik O, Rebets Y, Doud E, Meredith T, Luzhetskyy A, Bechthold A, Walker S, Fedorenko V - Open Biol (2013)

Bottom Line: Unlike the majority of actinomycete secondary metabolic pathways, the biosynthesis of peptidoglycan glycosyltransferase inhibitor moenomycin in Streptomyces ghanaensis does not involve any cluster-situated regulators (CSRs).Our work highlights an underappreciated strategy for secondary metabolism regulation, in which the interaction between structural genes and pleiotropic regulators is not mediated by CSRs.This strategy might be relevant for a growing number of CSR-free gene clusters unearthed during actinomycete genome mining.

View Article: PubMed Central - PubMed

Affiliation: Department of Genetics and Biotechnology, Ivan Franko National University of Lviv, Hrushevskoho st. 4, Lviv 79005, Ukraine.

ABSTRACT
Unlike the majority of actinomycete secondary metabolic pathways, the biosynthesis of peptidoglycan glycosyltransferase inhibitor moenomycin in Streptomyces ghanaensis does not involve any cluster-situated regulators (CSRs). This raises questions about the regulatory signals that initiate and sustain moenomycin production. We now show that three pleiotropic regulatory genes for Streptomyces morphogenesis and antibiotic production-bldA, adpA and absB-exert multi-layered control over moenomycin biosynthesis in native and heterologous producers. The bldA gene for tRNA(Leu)UAA is required for the translation of rare UUA codons within two key moenomycin biosynthetic genes (moe), moeO5 and moeE5. It also indirectly influences moenomycin production by controlling the translation of the UUA-containing adpA and, probably, other as-yet-unknown repressor gene(s). AdpA binds key moe promoters and activates them. Furthermore, AdpA interacts with the bldA promoter, thus impacting translation of bldA-dependent mRNAs-that of adpA and several moe genes. Both adpA expression and moenomycin production are increased in an absB-deficient background, most probably because AbsB normally limits adpA mRNA abundance through ribonucleolytic cleavage. Our work highlights an underappreciated strategy for secondary metabolism regulation, in which the interaction between structural genes and pleiotropic regulators is not mediated by CSRs. This strategy might be relevant for a growing number of CSR-free gene clusters unearthed during actinomycete genome mining.

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Related in: MedlinePlus

Levels of moenomycin production by various S. ghanaensis strains. Column labels: wt, ΔadpA—wild-type and adpAgh  mutant, respectively; wt adpA—wild-type strain overexpressing adpAgh; ΔbldA—bldAgh-minus mutant; wt bldA—wild-type strain overexpressing bldAgh; ΔabsB—absBgh-minus mutant; ΔabsB absB-exp—absBgh-minus mutant expressing plasmid for complementation pSOKEabsBgh-exp; wt absB-exp—wild-type strain overexpressing absBgh.
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RSOB130121F2: Levels of moenomycin production by various S. ghanaensis strains. Column labels: wt, ΔadpA—wild-type and adpAgh mutant, respectively; wt adpA—wild-type strain overexpressing adpAgh; ΔbldA—bldAgh-minus mutant; wt bldA—wild-type strain overexpressing bldAgh; ΔabsB—absBgh-minus mutant; ΔabsB absB-exp—absBgh-minus mutant expressing plasmid for complementation pSOKEabsBgh-exp; wt absB-exp—wild-type strain overexpressing absBgh.

Mentions: Deletion of adpAgh in the S. ghanaensis chromosome completely abolished moenomycin production, as determined by LC-MS (figure 2) and bioassays. No mass peaks corresponding to the earliest known moenomycin precursors [2] were found in the extracts of adpAgh mutant (ΔadpAgh), showing that moenomycin production was blocked at the initial first steps. Knockout of adpAgh had a significant influence on the morphological development S. ghanaensis. On solid media, a phenotype of S. ghanaensisΔadpAgh resembled that of the ‘bald’ (bld) mutants described for streptomycetes (figure 3 and [34]). AdpA proteins in other species are key developmental regulators, and their deletion has been reported to lead to substantial morphological defects [26,32,35].Figure 2.


Pleiotropic regulatory genes bldA, adpA and absB are implicated in production of phosphoglycolipid antibiotic moenomycin.

Makitrynskyy R, Ostash B, Tsypik O, Rebets Y, Doud E, Meredith T, Luzhetskyy A, Bechthold A, Walker S, Fedorenko V - Open Biol (2013)

Levels of moenomycin production by various S. ghanaensis strains. Column labels: wt, ΔadpA—wild-type and adpAgh  mutant, respectively; wt adpA—wild-type strain overexpressing adpAgh; ΔbldA—bldAgh-minus mutant; wt bldA—wild-type strain overexpressing bldAgh; ΔabsB—absBgh-minus mutant; ΔabsB absB-exp—absBgh-minus mutant expressing plasmid for complementation pSOKEabsBgh-exp; wt absB-exp—wild-type strain overexpressing absBgh.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3814723&req=5

RSOB130121F2: Levels of moenomycin production by various S. ghanaensis strains. Column labels: wt, ΔadpA—wild-type and adpAgh mutant, respectively; wt adpA—wild-type strain overexpressing adpAgh; ΔbldA—bldAgh-minus mutant; wt bldA—wild-type strain overexpressing bldAgh; ΔabsB—absBgh-minus mutant; ΔabsB absB-exp—absBgh-minus mutant expressing plasmid for complementation pSOKEabsBgh-exp; wt absB-exp—wild-type strain overexpressing absBgh.
Mentions: Deletion of adpAgh in the S. ghanaensis chromosome completely abolished moenomycin production, as determined by LC-MS (figure 2) and bioassays. No mass peaks corresponding to the earliest known moenomycin precursors [2] were found in the extracts of adpAgh mutant (ΔadpAgh), showing that moenomycin production was blocked at the initial first steps. Knockout of adpAgh had a significant influence on the morphological development S. ghanaensis. On solid media, a phenotype of S. ghanaensisΔadpAgh resembled that of the ‘bald’ (bld) mutants described for streptomycetes (figure 3 and [34]). AdpA proteins in other species are key developmental regulators, and their deletion has been reported to lead to substantial morphological defects [26,32,35].Figure 2.

Bottom Line: Unlike the majority of actinomycete secondary metabolic pathways, the biosynthesis of peptidoglycan glycosyltransferase inhibitor moenomycin in Streptomyces ghanaensis does not involve any cluster-situated regulators (CSRs).Our work highlights an underappreciated strategy for secondary metabolism regulation, in which the interaction between structural genes and pleiotropic regulators is not mediated by CSRs.This strategy might be relevant for a growing number of CSR-free gene clusters unearthed during actinomycete genome mining.

View Article: PubMed Central - PubMed

Affiliation: Department of Genetics and Biotechnology, Ivan Franko National University of Lviv, Hrushevskoho st. 4, Lviv 79005, Ukraine.

ABSTRACT
Unlike the majority of actinomycete secondary metabolic pathways, the biosynthesis of peptidoglycan glycosyltransferase inhibitor moenomycin in Streptomyces ghanaensis does not involve any cluster-situated regulators (CSRs). This raises questions about the regulatory signals that initiate and sustain moenomycin production. We now show that three pleiotropic regulatory genes for Streptomyces morphogenesis and antibiotic production-bldA, adpA and absB-exert multi-layered control over moenomycin biosynthesis in native and heterologous producers. The bldA gene for tRNA(Leu)UAA is required for the translation of rare UUA codons within two key moenomycin biosynthetic genes (moe), moeO5 and moeE5. It also indirectly influences moenomycin production by controlling the translation of the UUA-containing adpA and, probably, other as-yet-unknown repressor gene(s). AdpA binds key moe promoters and activates them. Furthermore, AdpA interacts with the bldA promoter, thus impacting translation of bldA-dependent mRNAs-that of adpA and several moe genes. Both adpA expression and moenomycin production are increased in an absB-deficient background, most probably because AbsB normally limits adpA mRNA abundance through ribonucleolytic cleavage. Our work highlights an underappreciated strategy for secondary metabolism regulation, in which the interaction between structural genes and pleiotropic regulators is not mediated by CSRs. This strategy might be relevant for a growing number of CSR-free gene clusters unearthed during actinomycete genome mining.

Show MeSH
Related in: MedlinePlus