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Identification, sequence analysis and phylogeny of the lef-2 gene of Helicoverpa armigera single-nucleocapsid baculovirus.

Abstract：

:The baculovirus late expression factor 2 (LEF-2) is involved in DNA replication, and most likely function as a primase processivity factor. Lef-2 genes have been found in multinucleocapsid nucleopolyhedroviruses (MNPVs) and in granuloviruses (GVs), but not yet in single-nucleocapsid NPV (SNPV). Here, a lef-2 gene homolog was identified from SNPV of Helicoverpa armigera (HearNPV). The open reading frame of the HearNPV lef-2 gene is 696 nucleotides long, encoding a putative protein of 232 amino acids with an M(r) of about 26 kDa. The 5'-noncoding region contains two early (CAGT) consensus motifs for transcription initiation and three TATA boxes. Lef-2 transcripts started at a C, 29 nucleotides upstream of a putative translational start. A putative polyA signal, AATAAA, was found 76 nucleotides downstream of the translation stop codon. The HearNPV lef-2 gene has a low but significant degree of amino acid sequence identity (30%) to the lef-2 genes of 15 other baculoviruses of which nine were newly determined. The N-terminal half of the LEF-2 proteins contains one (I) and the C-terminal half two (II and III) conserved domains. Sixteen amino acids are absolutely conserved in those LEF-2 investigated and are probably critical for LEF-2 function. A phylogenetic tree of 16 baculovirus LEF-2 proteins was constructed by using maximum parsimony analysis and appeared to be comparable to a tree for ecdysteroid UDP-glucosyl transferases (Chen et al., 1997a). The genomic location of the lef-2 genes relative to polyhedrin/granulin and the clade structure of the gene trees suggest that genome organization and gene phylogeny are useful parameters to study the evolutionary history of baculoviruses. These two independent approaches also give a more complete picture of the ancestral relationship among baculovirus.

journal_name

Virus Res

journal_title

Virus research

authors

Chen X,Ijkel WF,Dominy C,de Andrade Zanotto PM,Hashimoto Y,Faktor O,Hayakawa T,Wang CH,Prekumar A,Mathavan S,Krell PJ,Hu Z,Vlak JM

doi

10.1016/s0168-1702(99)00097-0

subject

Has Abstract

pub_date

1999-12-01 00:00:00

pages

21-32

issue

eissn

0168-1702

issn

1872-7492

pii

S0168170299000970

journal_volume

pub_type

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Identification, sequence analysis and phylogeny of the lef-2 gene of Helicoverpa armigera single-nucleocapsid baculovirus.