Molecular characterization of the Prospect Hill virus M RNA segment: a comparison with the M RNA segments of other hantaviruses.

Complementary DNA representing the genomic M RNA segment of the Prospect Hill (PH) Hantavirus was cloned and its nucleotide sequence determined. The PH virus M RNA segment is 3707 nucleotides in length and has a long open reading frame in the viral complementary-sense RNA with a coding capacity of 1142 amino acids. The predicted gene product of the PH virus M segment was compared with the corresponding gene products of Hantaan virus strain 76-118 (Hantaan), Sapporo rat virus strain SR-11 (SR) and Puumala virus strain Hällnäs B1 (Hällnäs). The amino acid sequence identities between the G1 and G2 proteins of PH virus and Hällnäs virus are respectively 74% and 79%. In contrast, the amino acid sequence similarities between the G1 proteins of PH virus and SR virus or Hantaan virus are only 50%. However the G2 proteins of SR and Hantaan viruses were more closely related to the G2 protein of PH virus with amino acid sequence similarities of approximately 62%. The G1 proteins of all four viruses had three potential asparagine-linked glycosylation sites conserved and there was one conserved site in the G2 proteins. Hydrophilicity plots of the four virus glycoproteins were very similar. The region of greatest hydrophilicity was conserved in the Hällnäs, SR and Hantaan viruses, and was located near the C terminus of the G1 protein, whereas the region of greatest hydrophilicity in the PH virus glycoprotein precursor is located closer to the N terminus of the G1 protein. Our data demonstrate that despite differences in the serotypic profiles and virulence of PH and Hällnäs viruses, their G1 and G2 proteins are closely related. We conclude that PH and Hällnäs viruses may have evolved along a separate evolutionary pathway in the Hantavirus genus from that of SR and Hantaan viruses.