灰斑古毒蛾核型多角体病毒三个晚期表达因子基因

Three Late Expression Factor Genes of Orgyia ericae Single-nucleocapsid Nucleopolyhedrovirus

将灰斑古毒蛾(Orgyiaericae)单粒包埋型核型多角体病毒(OrerSNPV)基因组DNA的各EcoRI酶切片段进行克隆和测序。序列分析结果表明EcoRI-M(3.0kb)与EcoRI-P片段(2.2kb)相连处含有编码晚期表达因子(LEF-2)的开放阅读框(ORF)。同时在EcoRI-E(约10kb)片段两端分别含有lef-3和lef-11基因的部分序列。lef-2基因编码区由648bp组成,可编码216个氨基酸残基的多肽,预计蛋白质分子量为23.7kDa。将OrerSNPVLEF-2氨基酸序列与其它已知的27种杆状病毒的LEF-2序列比较,发现OrerSNPV与其它鳞翅目NPVLEF-2氨基酸有35%～49%同源性,其中与BusuSNPV、MaMNPV-A、HezeSNPV、HearSNPV和LdMNPV同源性最高,和GV有26%～31%同源性,与膜翅目松柏锯角叶蜂NPV的同源性为32%,与库蚊杆状病毒的同源性只有23%。根据氨基酸序列绘制的分子进化树表明28种杆状病毒lef-2基因可以分为鳞翅目NPV、GV、膜翅目NeseNPV与双翅目CulexnigripalpusBaculovirus四个分支。OrerSNPVlef-2与BusuSNPV在进化树上关系最为接近,而OrerSNPVlef-3和LdMNPV的最接近,OrerSNPVlef-11则和SeMNPV的关系最接近。

Genomic DNA of Orgyia ericae single-nucleocapsid nucleopolyhedrovirus (OrerSNPV) was digested with the restriction enzyme EcoRI and the fragments were cloned into the plasmid pUC19 to build a library for sequencing. An ORF encoding the LEF-2 was identified from the cloned EcoRI-M (3.0kb)and EcoRI-P(2.2kb)fragments with 648 bp in length and potential to encode a 216 amino acid polypeptide with predicted molecular weight of 23.7 kD. In addition, two ORFs encoding the partial LEF-3 and LEF-11 were identified from two ends of the cloned EcoRI-E (about 10 kb). Comparison analysis showed that OrerSNPV LEF-2 amino acid sequence shared 35%-49% identities with those of other 27 reported lepidopteran NPV LEF-2s, and the highest identities with BusuSNPV, MacoNPV-A, Helicoverpa zea single-nucleocapsid nucleopolyhedrovirus (HezeSNPV), Helicoverpa armigera single- nucleocapsid nucleopolyhedrovirus (HearSNPV) and Lymantria dispar multiple-nucleocapsid nucleopoly- hedrovirus (LdMNPV). OrerSNPV LEF-2 also shared 26%-31%, 32% and 23% identities with those from lepidopteran GVs, the hymenopteran NPV (Neodiprion sertifer nucleopolyhedrovirus, NeseNPV) and the dipteran virus (Culex nigripalpus Baculovirus). Phylogenetic tree based on the amino acid sequences showed the 28 baculovirus LEF-2s could be divided into 4 branches, NPVs, GVs, NeseNPV and Culex nigripalpus Baculovirus. OrerSNPV lef-2 gene was most closely related to Buzura suppressaria single- nucleocapsid nucleopolyhedrovirus (BusuSNPV), while OrerSNPV was most closely related to LdMNPV in the phylogenetic tree based on LEF-3 sequences and to Spodoptera exigua multiple- nucleocapsid nucleopolyhedrovirus (SeMNPV) in the tree of LEF-11. EMBL Accession numbers for the nucleotide sequences of the lef-2, lef-3 and lef-11 are AJ629189, AJ715478 and AJ715479, respectively.