期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1987
卷号：84
期号：8
页码：2130-2134
DOI：10.1073/pnas.84.8.2130
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Galactose utilization in Streptomyces lividans was shown to be controlled by an operon that is induced in the presence of galactose and repressed by glucose. Two promoters, galP1 and galP2, which direct transcription of two distinct polycistronic transcripts, have been identified. galP1 is located immediately upstream of the operon and is induced in the presence of galactose. This promoter directs transcription of the galT, galE, and galK genes. The second promoter, galP2, is located within the operon just upstream of the galE gene. This promoter is responsible for constitutive transcription of the galE and galK genes. Comparison of the S. lividans gal operon to the Escherichia coli gal operon indicates the presence of a constitutive promoter positioned upstream of galE in both operons. We suggest that coupling the operon's constitutive promoter to the galE gene fulfills a physiological requirement for constitutive UDPgalactose 4-epimerase expression in Streptomyces.
