title: Complete sequences of the glycoproteins and M RNA of Punta Toro phlebovirus compared to those of Rift Valley fever virus.
abstract: The complete sequence of Punta Toro virus (Phlebovirus, Bunyaviridae) middle size (M), RNA has been determined. The RNA is 4330 nucleotides long (mol wt 1.46 X 10(6), base composition: 26.7% A, 33.6% U, 18.5% G, 21.2% C) and has 3'- and 5'-terminal sequences that, depending on the arrangement, are complementary for some 15 residues. The viral RNA codes in its viral-complementary sequence for a single primary gene product (the viral glycoprotein precursor) that is comprised of 1313 amino acids (146,376 Da) and is abundant in cysteine residues but has few potential asparagine-linked glycosylation sites. The 5'-noncoding region of the Punta Toro M viral-complementary RNA is short (16 nucleotides); the 3'-noncoding sequence is much longer (372 nucleotides). The latter is rich in short stretches of adenylate residues, like the 3'-noncoding regions of the Punta Toro S mRNA species (T. Ihara, H. Akashi, and D. H. L. Bishop, 1984, Virology 136, 293-306). No other large open reading frame has been identified in either the viral, or viral-complementary, M RNA sequences. Limited amino-terminal sequence analyses of the two viral glycoproteins have indicated the gene order and potential cleavage sites in the glycoprotein precursor. The data suggest the existence of a 30 X 10(3)-Da polypeptide (designated NSM) in the glycoprotein precursor that precedes the G1 protein (i.e., gene product order: NSM-G1-G2). Examination of the sequence of the Punta Toro M gene product reveals the presence of multiple hydrophobic sequences including a 19-amino acid, carboxy-proximal, hydrophobic region (G2). This hydrophobic sequence is followed by a 13-amino acid-terminal sequence rich in charged amino acids. The size and constitution of the carboxy-terminal region is consistent with a transmembranal and anchor function for the glycoprotein in the viral envelope. Other regions of the glycoprotein precursor contain sequences of amino acids with a predominantly hydrophobic character (23, 50, and 20 amino acids in length). Their functions are unknown. The amino terminus of the G1 protein is located near the end of the 23-amino acid-long hydrophobic sequence of the presumptive precursor, the hydrophobic 50-amino acid sequence lies within G1, and the amino terminus of G2 is located in the middle of the 20-amino acid-long hydrophobic sequence.(ABSTRACT TRUNCATED AT 400 WORDS)
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002043:Bunyaviridae / Q000235:genetics*; D002460:Cell Line; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D004247:DNA / Q000032:analysis; D006023:Glycoproteins / Q000235:genetics*; D007668:Kidney; D009693:Nucleic Acid Hybridization; D016856:Phlebovirus / Q000235:genetics*; D012367:RNA, Viral / Q000235:genetics*; D012296:Rift Valley fever virus / Q000235:genetics*; D013045:Species Specificity; D014764:Viral Proteins / Q000235:genetics*
chemical_list: D006023:Glycoproteins; D012367:RNA, Viral; D014764:Viral Proteins; D004247:DNA