A Vibrio harveyi insertional mutant in the cgtA (obg, yhbZ) gene, whose homologues are present in diverse organisms ranging from bacteria to humans and are essential genes in many bacterial species.
The cgtA gene product is a member of the subfamily of small GTP-binding proteins that have been identified in diverse organisms ranging from bacteria to humans. In bacteria that sporulate or display another special developmental programme, this gene (referred to as cgtA, obg or yhbZ) appears to be involved in the regulation of these processes. However, this gene has also been found to be essential in all bacterial species investigated to date, although its role in bacteria that do not sporulate and do not undergo a specific development remains unknown. Here the authors characterize a Vibrio harveyi mutant bearing a transposon insertion into the cgtA gene. This mutant reveals a multiple phenotype: it grows more slowly than the wild-type strain in a rich medium; its growth is completely inhibited in minimal media; its survival in 3% NaCl is dramatically reduced; it is very sensitive to UV irradiation; it is more susceptible to mutation upon treatment with different mutagens; its luminescence is decreased; its quorum-sensing regulation is less effective than in the wild-type strain; and the elongated shape of the mutant cells may suggest problems with the regulation of cell division and/or DNA replication. These defects in diverse cellular processes found in the insertional cgtA mutant of V. harveyi indicate that in a bacterium that does not sporulate and does not display other special development programmes, the CgtA protein is involved in the regulation of many crucial biochemical reactions, possibly at the stage of signal transduction.
Czyz
A
A
Laboratory of Molecular Biology (affiliated with the University of Gdansk), Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Kladki 24, 80-822 Gdansk, Poland.
Zielke
R
R
Konopa
G
G
Wegrzyn
G
G
D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D015964:Gene Expression Regulation, Bacterial; D020043:Genes, Essential; D006801:Humans; D008969:Molecular Sequence Data; D020559:Monomeric GTP-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D016254:Mutagenesis, Insertional; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D014733:Vibrio / Q000145:classification* / Q000235:genetics / Q000502:physiology*
D001426:Bacterial Proteins; D004251:DNA Transposable Elements; C108621:CgtA protein, bacteria; D020559:Monomeric GTP-Binding Proteins