DasSarma S, Damerval T, Jones J G, Tandeau de Marsac N
Départment de Biochimie et Génétique Moléculaire, Institut Pasteur, Paris, France.
Mol Microbiol. 1987 Nov;1(3):365-70. doi: 10.1111/j.1365-2958.1987.tb01943.x.
The halophilic archaebacterium, Halobacterium halobium, displays spontaneous and revertible genetic variability for the gas vesicle phenotype (Vac) at frequencies as high as 0.5 to 5%. To investigate the mechanism of these high-frequency mutations, we have cloned a gas vesicle protein gene (gvpA) from the Vac+ wild-type H. halobium strain, NRC-1, and determined its nucleotide sequence, transcription start site, and genomic location. The gene sequence predicts that the gas vesicle protein has a molecular weight of 9156 and is relatively hydrophobic except for a hydrophilic C-terminal region. Northern hybridization analysis shows that the gene is transcribed into a 350-nucleotide mRNA, and primer extension analysis indicates that transcription begins 20 nucleotides upstream of the ATG start codon. Southern hybridization analysis shows that the gene is encoded by a large H. halobium plasmid. We discuss potential mechanisms for genetic variability of the Vac phenotype and identify sequences in the gvpA promoter region which may function as signals for transcription in H. halobium.
嗜盐古细菌盐生盐杆菌（Halobacterium halobium）的气荚膜表型（Vac）呈现出自发性且可回复的遗传变异性，频率高达0.5%至5%。为了研究这些高频突变的机制，我们从Vac⁺野生型盐生盐杆菌菌株NRC-1中克隆了一个气荚膜蛋白基因（gvpA），并确定了其核苷酸序列、转录起始位点和基因组位置。基因序列预测气荚膜蛋白的分子量为9156，除了亲水性的C末端区域外相对疏水。Northern杂交分析表明该基因转录成一条350个核苷酸的mRNA，引物延伸分析表明转录起始于ATG起始密码子上游20个核苷酸处。Southern杂交分析表明该基因由盐生盐杆菌的一个大质粒编码。我们讨论了Vac表型遗传变异性的潜在机制，并鉴定了gvpA启动子区域中可能作为盐生盐杆菌转录信号的序列。
