Identification and characterization of the genes encoding three structural proteins of the Thermoproteus tenax virus...

Three structural proteins, TP1, TP2 and TP3, of the virus TTV1 of the thermophilic archaebacterium Thermoproteus tenax strain Kra1 were mapped within the viral genome by locating the amino-terminal amino acid sequences of these proteins in the TTV1 DNA sequence. The derived amino acid sequences comprise 113, 139 and 160 amino acid residues, respectively. All three proteins are hydrophobic. The three genes are not linked, but transcribed in the same direction. No Shine-Dalgarno sequences are found in the vicinity of the initiation codons of these three genes. By Northern analysis, four mRNAs of 0.5 kb, 0.8 kb, 1.1 kb and 1.8 kb in size were found to be encoded in the region and in the vicinity of the genes, the shortest one (t1) encoding TP3 and the longest one (t4) encoding TP2. No transcript from the region encoding TP1 has been found so far. A transcriptional start site was mapped for the transcript t1. Its upstream sequence was similar to the putative consensus sequence for archaebacterial promoters.