Sequence Analysis of 4.0 kb Region Upstream of the Chitinase Gene of Spodoptera litura Nucleopolyhedrovirus / 中国病毒学

ABSTRACT

The region of about 4.0 kb upstream of Spodoptera litura nucleopolyhedrovirus (SpltNPV) chiA gene was sequenced, in which six open reading frames(ORF1～6) were found. These ORFs are 156, 297, 540, 369, 1281, and 228 nucleotides long, encoding the proteins of 51, 98, 179, 122, 426, and 75 amino acids with the molecular weight of 6.15 kD, 11.46 kD, 21.70 kD, 14.69 kD, 47.59 kD, and 9.09 kD respectively. One early promoter motif CAGT in ORF1 and ORF3, two early promoter motifs CAGT in ORF2, one late promoter motif TAAG in ORF4 and two late promoter motifs TAAG in ORF5 were found in 5′noncoding regions of these ORFs. The polyadenylation signals, AATAAA, are located downstream of the translation stop codon of ORF1, ORF4 and ORF5. ORF4 is the homologous gene of AcMNPV ORF53, BmNPV ORF42, OpMNPV ORF56 and LdMNPV ORF54. Compared with all genes from baculoviruses, ORF1, ORF2 and ORF6 have no homologous genes. It is suggested that ORF1, ORF2 and ORF6 may be three novel baculovirus genes.