[Cloning and analysis of genes in the halocin C8 gene cluster]

Halocin C8 (HalC8), produced by a halophilic archaeon strain AS7092, is a gene-coded peptide microhalocin and has a wide inhibitory spectrum against the members of haloarchaea. To investigate the mechanisms of the gene expression regulation, the peptide processing and transportation of this halocin, a 9.3kb DNA gene cluster containing the halocin C8 encoding gene (proC8) and other possible involved genes was cloned, by screening of a genomic library of AS7092 as well as anchoring PCR technique. Sequence analysis indicated that it contained at least six open reading frames, including halU, halR, proC8, halT1, halT2 and halT3. The gene halU encodes a membrane-spanning protein HalU, but its function is unknown. The gene halR encodes a putative regulator protein HalR, its function was deduced to regulate the transcription of proC8 gene, which encodes the precursor for halocin C8. The gene halT1, halT2 and halT3 likely encode the transporters HalT1, HalT2 and HalT3, the functions of which were speculated to transport the halocin C8 out of the cellular membrane. This is the first report of gene cluster cloning for any halocin.