RESUMO
Andean potato mottle virus (APMV) is a comovirus whose genomic structure consists of two plus-strand RNA molecules (M- and B-RNA). Here we report the nucleotide sequence analysis of an APMV M-RNA cDNA clone with 3,669 nucleotide (nt) residues, exclusive of the polyadenylate at the 3' end, covering approximately 99% of the APMV M-RNA. The first initiation codon in register translates from nt 194 to 3185 a polyprotein of 997 amino acid (aa) residues. A second initiation codon in register, beginning at nt position 416, translates a polyprotein of 923 aa. The cleavage sites used in the processing of polyprotein were identified in the long open reading frame by N-terminal microsequencing of the large coat protein (LCP) and the small coat protein (SCP). These dipeptide cleavage sites are Q/M for the LCP and Q/F for the SCP. In a comparison of the deduced APMV polyprotein aa sequence with those of four other comoviruses, the coding regions for the putative movement protein, LCP and SCP, were found similar in length in all five species. Multiple alignment of the M-RNA sequences for each of the three genes from the five comoviruses revealed different degrees of homology. APMV was always the least homologous of the five comoviruses, showing significant aa substitutions in positions where the other comoviruses have identical residue or conservative substitutions.
Assuntos
Comovirus/genética , RNA Viral/genética , Proteínas Virais/genética , Sequência de Aminoácidos , Sequência de Bases , Brasil , Capsídeo/genética , Clonagem Molecular , Comovirus/classificação , Comovirus/isolamento & purificação , DNA Complementar/genética , DNA Viral/genética , Genes Virais , Dados de Sequência Molecular , Homologia de Sequência de Aminoácidos , Solanum tuberosum/microbiologia , Especificidade da EspécieRESUMO
Andean potato mottle virus (APMV), an endemic South American comovirus, has a bipartite genome consisting of two plus-strand RNA molecules (M and B RNA). We have cloned the 3' half of the B RNA and identified the complete sequence of the putative APMV RNA polymerase. The RNA polymerase gene is part of a large polyprotein-encoding open reading frame. The putative, mature RNA polymerase, as deduced by comparison with the related cowpea mosaic virus (CPMV), type member of the comovirus group, is 703 amino acids long and shows a large degree of similarity with CPMV and other RNA polymerases.