Romero J, Dzianott A M, Bujarski J J
Northern Illinois University, Department of Biological Sciences, DeKalb 60115.
Virology. 1992 Apr;187(2):671-81. doi: 10.1016/0042-6822(92)90470-a.
Complete nucleotide sequences of broad bean mottle virus (BBMV) genomic RNAs 2 and 3 were determined. They consist of 2811 and 2293 nucleotides, respectively. Both RNAs are caped and, unlike in other tricornaviruses, both initiate with an A residue. BBMV RNA2 is monocistronic and encodes an 815 amino acid 2a protein, whereas RNA3 is dicistronic, encoding for a 295 amino acid 3a protein and for the 190 amino acid coat protein. A central, 423 amino acid 2a protein core region is highly homologous among the three bromoviruses, whereas both N- and C-termini are more heterologous. Most of the homologies among 3a proteins are concentrated within the N-termini two-thirds of the molecule that is predominantly hydrophobic, whereas the C-terminal one-third contains a large number of charged amino acids. The homologies among coat proteins are clustered within several mostly hydrophobic, or neutral, domains. The 5' noncoding region of the RNA2 has 110 nucleotides, whereas that of RNA3 contains 330 nucleotides. As in cowpea chlorotic mottle virus, but unlike in Brome mosaic virus, the 5' noncoding region includes subgenomic promoter-like sequences. The BBMV RNA3 intercistronic region also has subgenomic promoter sequences and contains a long poly(A) stretch. At the 3' end, BBMV RNAs 2 and 3 have 257 and 236 noncoding nucleotides, respectively.
测定了蚕豆斑驳病毒（BBMV）基因组RNA2和RNA3的完整核苷酸序列。它们分别由2811和2293个核苷酸组成。两种RNA均有帽结构，与其他三叶草病毒不同的是，二者均以A残基起始。BBMV RNA2是单顺反子，编码一个815个氨基酸的2a蛋白，而RNA3是双顺反子，编码一个295个氨基酸的3a蛋白和190个氨基酸的外壳蛋白。三种雀麦花叶病毒的2a蛋白核心区域有423个氨基酸，高度同源，而N端和C端则更具异源性。3a蛋白之间的同源性大多集中在分子N端的三分之二区域，该区域主要是疏水性的，而C端的三分之一区域含有大量带电荷的氨基酸。外壳蛋白之间的同源性集中在几个大多为疏水性或中性的结构域内。RNA2的5'非编码区有110个核苷酸，而RNA3的5'非编码区含有330个核苷酸。与豇豆褪绿斑驳病毒一样，但与雀麦花叶病毒不同的是，5'非编码区包含亚基因组启动子样序列。BBMV RNA3的顺反子间区域也有亚基因组启动子序列，并含有一段长的聚腺苷酸序列。在3'端，BBMV RNA2和RNA3分别有257和236个非编码核苷酸。
