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The gene for a halophilic β‐galactosidase ( bga H) of Haloferax alicantei as a reporter gene for promoter analyses in Halobacterium salinarum
Author(s) -
Patenge Nadja,
Haase Andrea,
Bolhuis Henk,
Oesterhelt Dieter
Publication year - 2000
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.2000.01831.x
Subject(s) - halobacterium salinarum , biology , haloferax volcanii , halophile , reporter gene , gene , promoter , archaea , gene expression , halobacterium , biochemistry , microbiology and biotechnology , genetics , bacteria
Investigations of transcriptional regulation and the characterization of promoters in homologous expression systems are most easily performed using suitable reporter genes. Presumably because of the high internal salt concentration in halophilic Archaea, the successful application of the commonly used reporter genes has not been reported so far. Recently, the gene for an extremely halophilic β‐galactosidase ( bga H) from Haloferax alicantei has become available. After transformation of Halobacterium salinarum with a vector‐carrying bga H, the enzyme activity in cell lysates could be readily determined by a simple colorimetric assay and colonies could be screened for activity on plates containing Xgal substrate. Expression of bga H under the control of various halobacterial promoters of known strength led to different specific β‐galactosidase activities in the lysates. Using Northern blot hybridization and semiquantitative RT‐PCR, it was shown that the bga H transcript level corresponded to the specific enzyme activity. Therefore, the bga H gene of Haloferax alicantei appears to be a useful tool for in vivo studies of gene expression in Halobacterium salinarum and possibly other halophilic Archaea.