GvpE- and GvpD-mediated transcription regulation of the p-gvp genes encoding gas vesicles in Halobacterium salinarum

• Published in: Microbiology (Society for General Microbiology) Vol. 150; no. 6; pp. 1829 - 1838
• Main Authors: Hofacker, Annette, Schmitz, Kerstin-Maike, Cichonczyk, Alexander, Sartorius-Neef, Simone, Pfeifer, Felicitas
• Format: Journal Article
• Language: English
• Published: Reading Soc General Microbiol 01.06.2004; Society for General Microbiology
• Subjects: Archaeal Proteins - genetics; Archaeal Proteins - metabolism; Bacterial plant pathogens; Bacteriological methods and techniques used in bacteriology; Bacteriology; Base Sequence; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Archaeal; Genes, Archaeal; Genes, Reporter; Halobacterium salinarum; Halobacterium salinarum - genetics; Halobacterium salinarum - metabolism; Microbiology; Miscellaneous; Molecular Sequence Data; Phytopathology. Animal pests. Plant and forest protection; Promoter Regions, Genetic; Proteins - genetics; Proteins - metabolism; Transcription, Genetic; Transformation, Bacterial; Nucleotide sequence; Transcription; Archaeobacteria; Enzyme; Haloferax volcanii; Consensus; Protein; Halobacterium salinarum; Endogenous; Reporter gene; Mutagenesis; Glycosidases; Halobacteriales; Bacteria; Hydrolases; Mutation; Halobacteriaceae; O-Glycosidases; Hybrid gene; β-Galactosidase
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/mic.0.27078-0

Institut für Mikrobiologie und Genetik, Technische Universität Darmstadt, Schnittspahnstr. 10, D-64287 Darmstadt, Germany Correspondence Felicitas Pfeifer pfeifer{at}bio.tu-darmstadt.de The transcription of the 14 p- gvp genes involved in gas vesicle formation of Halobacterium salinarum PHH1 is driven by the four promoters pA, pD, pF and pO. The regulation of these promoters was investigated in Haloferax volcanii transformants with respect to the endogenous regulatory proteins GvpE and GvpD. Northern analyses demonstrated that the transcription derived from the pA and pD promoters was enhanced by GvpE, whereas the activities of the pF and pO promoters were not affected. Similar results were obtained using promoter fusions with the bgaH reporter gene encoding an enzyme with -galactosidase activity. The largest amount of specific -galactosidase activity was determined for pA- bgaH transformants, followed by pF- bgaH and pD- bgaH transformants. The presence of GvpE resulted in a severalfold induction of the pA and pD promoter, whereas the pF promoter was not affected. A lower GvpE-induced pA promoter activity was seen in the presence of GvpD in the pA- bgaH /DE ex transformants, suggesting a function of GvpD in repression. To determine the DNA sequences involved in the GvpE-mediated activation, a 50-nucleotide region of the pA promoter was investigated by 4-nucleotide scanning mutagenesis. Some of these mutations affected the basal transcription, especially mutations in the region of the TATA box and the putative BRE sequence element, and also around position –10. Mutant E, harbouring a sequence with greater identity to the consensus BRE element, showed a significantly enhanced basal promoter activity compared to wild-type. Mutations not affecting basal transcription, but yielding a reduced GvpE-mediated activation, were located immediately upstream of BRE. These results suggested that the transcription activation by GvpE is in close contact with the core transcription machinery. The GenBank accession numbers for the p-vac subfragment sequences reported in this paper are X64729 (p- gvpACNO ) and X55648 (p- gvpDEFGHIJKLM ). Present address: Klinische Pharmakologie, Klinikum der Universität Frankfurt, Theodor Stern Kai 7, D-60590 Frankfurt, Germany.