Galinski M S, Mink M A, Pons M W
Division of Molecular Virology, James N. Gamble Institute of Medical Research, Cincinnati, Ohio 45219.
Virology. 1988 Aug;165(2):499-510. doi: 10.1016/0042-6822(88)90594-6.
The sequence of the gene encoding the L protein of the human parainfluenza 3 virus was determined by direct dideoxy sequence analysis of the genomic 50 S RNA and confirmed by molecular cloning and sequence analysis of recombinant clones. A series of three overlapping clones was generated by primer extension using genomic 50 S RNA as the template. These clones originate within the 5' end of the hemagglutinin-neuraminidase gene, span the entire L gene, and extend into the extracistronic 5' end of the viral RNA. The L gene extends 6755 nucleotides (inclusive of the putative transcription initiation and polyadenylation signal sequences) and encodes a protein consisting of 2233 amino acids (MW 255,812). There are 44 nucleotides downstream of the putative polyadenylation signal sequence which may represent a negative-strand leader. The complementary sequence of the extracistronic region is nearly identical to the 3' end of the viral RNA. Thirty-three of the first thirty-nine nucleotides of the 3' ends of the plus and minus strands are conserved. Comparison of amino acid sequence homology with other paramyxoviral L proteins indicates a high degree of sequence conservation with Sendai virus (62%) and Newcastle disease virus (28%). In addition, four smaller regions were identified which shared extensive homology with the L protein of vesicular stomatitis virus, a member of the Rhabdoviridae family.
通过对基因组50S RNA进行直接双脱氧序列分析，确定了人副流感3病毒L蛋白编码基因的序列，并通过重组克隆的分子克隆和序列分析进行了确认。以基因组50S RNA为模板，通过引物延伸产生了一系列三个重叠克隆。这些克隆起源于血凝素神经氨酸酶基因的5'端，跨越整个L基因，并延伸到病毒RNA的顺反子外5'端。L基因延伸6755个核苷酸（包括推定的转录起始和聚腺苷酸化信号序列），编码一个由2233个氨基酸组成的蛋白质（分子量255,812）。推定的聚腺苷酸化信号序列下游有44个核苷酸，可能代表负链前导序列。顺反子外区域的互补序列与病毒RNA的3'端几乎相同。正链和负链3'端的前39个核苷酸中有33个是保守的。与其他副粘病毒L蛋白的氨基酸序列同源性比较表明，与仙台病毒（62%）和新城疫病毒（28%）有高度的序列保守性。此外，还鉴定出四个较小的区域，它们与弹状病毒科成员水疱性口炎病毒的L蛋白有广泛的同源性。
