Cloning and nucleotide sequencing of the S4 genome segment of avian reovirus S1133

Summary

The sequence of RNA genome segment S4 of the avian reovirus (ARV) strain S1133 was determined. S4 RNA is 1185 base pairs long and contains one open reading frame encoding a protein of 367 amino acid residues (40.6 kDa), the similar size as the known S4 gene product (σ NS), with a net charge of −1 at neutral pH. The S4 RNA sequence possesses a pentanucleotide sequence UCAUC at the 3′-terminus of its plus strand like in ARV S1 and S3 segments and ten segments of mammalian reovirus (MRV). The predicted amino acid sequence comparison revealed that the homology is 44.02%, 45.71%, and 42.33% for ARV σ NS and three serotypes of MRV σ NS, respectively. The relatively high content of α-helix structure in the C-terminal portion of ARV σ NS suggests that this protein may functionally relate to MRV σ NS. Northern blot hybridization showed that a ³²P-labeled cDNA insert S4-49 from ARV S4 RNA cross-hybridized with the corresponding RNA segments of all seven strains of ARV tested.