Expression analysis of the spi gene in the pock-forming plasmid pSA1.1 from Streptomyces azureus and localization of its product during differentiation

The sporulation inhibitory gene spi in the pock-forming conjugative plasmid pSA1.1 of Streptomyces azureus was introduced into cells via a high or low copy number vector to examine the effect of gene dosage on the growth of Streptomyces lividans TK24 as a host. In transformants carrying a high spi c...

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Bibliographic Details
Published in:Applied microbiology and biotechnology 2012-08, Vol.95 (3), p.707-716
Main Authors: Doi, Katusmi, Ohyama, Yukiko, Yokoyama, Eiji, Nishiyama, Takashi, Fujino, Yasuhiro, Nagayoshi, Yuko, Ohshima, Toshihisa, Ogata, Seiya
Format: Article
Language:English
Subjects:
Antibiotics
Applied Genetics and Molecular Biotechnology
Bacterial Proteins - analysis
Bacterial Proteins - genetics
Binding sites
Biomedical and Life Sciences
Biotechnology
Copy number
Cytosol - chemistry
Differentiation
Dosage
E coli
Elongation
Fluorescence
Gene Dosage
Gene Expression Profiling
Genes
Genetic engineering
Genotype & phenotype
Green fluorescent protein
Hyphae
Image enhancement
Life Sciences
Localization
Microbial Genetics and Genomics
Microbiology
Microscopy, Confocal
Morphology
Mycelia
Plasmids
Proteins
Septation
Sporulation
Streptomyces
Streptomyces - chemistry
Streptomyces - cytology
Streptomyces - genetics
Streptomyces - growth & development
Substrates
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Summary:The sporulation inhibitory gene spi in the pock-forming conjugative plasmid pSA1.1 of Streptomyces azureus was introduced into cells via a high or low copy number vector to examine the effect of gene dosage on the growth of Streptomyces lividans TK24 as a host. In transformants carrying a high spi copy number, nutrient mycelial growth was inhibited, as was morphological differentiation from substrate mycelium to aerial mycelium on solid media. The degree of inhibition depended on the spi gene dosage, but the presence of pSA1.1 imp genes, which encode negative repressor proteins for spi , relieved the inhibition. Confocal images of Spi tagged with enhanced green fluorescent protein in cells on solid media revealed that spi expression was initiated at the time of elongation of substrate mycelium, that its expression increased dramatically at septation in aerial hyphae, and that the expression was maximal during prespore formation. Expression of spi covered the whole of the hyphae, and the level of expression at the tip of the hyphae during prespore formation was about sixfold greater than during substrate mycelial growth and threefold greater than during aerial mycelial growth. Thus, localized expression of spi at particular times may inhibit sporulation until triggering imp expression to repress its inhibitory effects.
ISSN:0175-7598
1432-0614
DOI:10.1007/s00253-012-4000-9