Conserved and non-conserved regions in the Sendai virus genome: evolution of a gene possessing overlapping reading frames.
We have sequenced the entire genome of a virulent field isolate of Sendai virus, the Hamamatsu strain, and compared the sequence with that of a distant related strain, the Z strain. Calculation of synonymous and non-synonymous (amino acid changing) nucleotide substitutions revealed regions where changes were permissive and non-permissive, and the experimentally determined functional region were found to be conserved, showing that important regions for function were conserved during evolution. In the cistron-overlapping regions in the P gene, one reading frame was conserved, whereas the other overlapping frame was flexible. The priority of one frame could be a strategy for evolution of an overlapping gene of RNA viruses. We found that the carboxyl two thirds of the C protein was conserved over the amino-terminal one third, possessing priority to the overlapping P polypeptide. This suggests that the carboxyl two thirds of the C protein have a functional importance. We also found a highly variable region between the L coding frame and the 5' trailer sequence. The relevance of these findings to actual viral replication should be clarified in the future.
Fujii
Y
Y
Department of Bacteriology, Hiroshima University School of Medicine, Japan.
Kiyotani
K
K
Yoshida
T
T
Sakaguchi
T
T
D001483:Base Sequence; D017124:Conserved Sequence; D019143:Evolution, Molecular; D016679:Genome, Viral; D008969:Molecular Sequence Data; D019590:Nucleocapsid Proteins / Q000235:genetics; D010750:Phosphoproteins / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D018108:Respirovirus / Q000145:classification / Q000235:genetics*; D017422:Sequence Analysis, DNA; D014764:Viral Proteins / Q000235:genetics*
D019590:Nucleocapsid Proteins; C055859:P protein, Sendai virus; D010750:Phosphoproteins; D014764:Viral Proteins