ISSN:
1617-4623
Keywords:
Key wordsStreptomyces
;
LysR-type repressor
;
stg gene repression
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract A 3240-bp DNA fragment, located next to the puromycin biosynthetic gene cluster of Streptomycesalboniger, contains three complete ORFs in the order: stgA, stgU and stgR. The transcriptional orientation of stgA is opposite to that of stgU and stgR. Each gene is expressed from its own promoter, although stgU and stgR can be cotranscribed. The deduced amino acid sequences of their products present similarities to a variety of pyridoxal-phosphate-dependent aspartate aminotransferases (StgA), several proteins of unknown function (StgU), and the LysR-type of transcriptional regulators (StgR). In a ΔstgR null mutant of S. alboniger, transcription of stgA and stgU is increased with respect to that in the wild type. In addition, in vivo experiments with promoter-probe plasmids indicated that in the ΔstgR mutant, stgA- or stgU-promoter-dependent expression of the reporter gene was up to three-fold higher than in the wild type. Taken together, these results indicate that StgR is a LysR-type transcriptional repressor of both stgA and stgU.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s004380050838
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