Structural organization of the genomic region between genes 30 and 31 in T4-related bacteriophages LZ, LZ1 and LZ9

Abstract

We have determined the nucleotide sequence and organization of the genomic region between genes 30 and 31 in the T4-related bacteriophages LZ, LZ1 and LZ9. In case of T4, this region has been shown to contain eleven coding sequences and several regulatory elements, including two early, two middle and one late promoters. The sequence analysis of LZ, LZ1 and LZ9 revealed that the most diverged part of the genomic region 30–31 in these phages lies within the early gene cluster 30.9–30.3. A new orthologue of T4 30.8 was revealed in LZ1. Two individual open reading frames, 30.4A and 30.4B, replaced the counterpart of T4 gene 30.4 in LZ, while any counterparts of T4 genes 30.8 and 30.5 were absent at all. No analogues of T4 genes 30.7 and 30.8 were found in phage LZ9. One of two early promoters was absent in LZ and LZ9. Moreover, the intergenic region between genes rIII and 30.9 of LZ9 appears to contain the 153 nt insertion, forming new hypothetical ORF. Keywords: T4-related bacteriophages, phage LZ, phage LZ1, phage LZ9, genomic region 30–31