Baculoviruses contain a gene for the large subunit of ribonucleotide reductase.

Abstract

In the genomes of two baculoviruses, Spodoptera exigua and S. littoralis multicapsid nucleopolyhedroviruses (SeMNPV and SpliMNPV, respectively), an open reading frame (ORF) encoding the large subunit of ribonucleotide reductase (RR1) was identified. The predicted amino acid sequences of SeMNPV and SpliMNPV RR1 showed high homology to RR1 proteins from eukaryotes (ca. 70 % and 80 % similarity, respectively). The amino acid residues thought to be involved in catalytic function were conserved in the baculoviral RR1 ORFs. The RR1 ORFs in SeMNPV and SpliMNPV were located in different genomic positions. In SeMNPV, the RR1 ORF was located upstream of the polyhedrin gene, in an anti-genomic orientation. In SpliMNPV, the RR1 ORF preceded the p74 gene. By searching databanks, sequences homologous to the N ter-

Specificity of multiple homologous genomic regions in Spodoptera exigua nucleopolyhedrovirus DNA replication.

“…Plasmid pSeEcoRI-2.2, containing the SeMNPV ubiquitin gene, was described previously by van Strien et al (1996). The fragments that hybridized to RB-33 were cloned and analysed.…”

“…The SeMNPV-US isolate (Gelernter & Federici, 1986) and the AcMNPV E2 strain (Smith & Summers, 1978) were produced using S. exigua fourth instar larvae. Routine cell culture BFGE Homologous regions of Spodoptera exigua MNPV DNA Homologous regions of Spodoptera exigua MNPV DNA maintenance and AcMNPV and SeMNPV infection procedures were carried out according to published procedures (Summers & Smith, 1987 ;van Strien et al, 1996 ;Heldens et al, 1996). The SeMNPV plasmid and cosmid libraries were described previously (Heldens et al, 1996).…”

“…A detailed restriction map and an overlapping cosmid library of SeMNPV DNA have recently become available (Heldens et al, 1996). Several SeMNPV genes have been identified such as those encoding polyhedrin, p10, rr1 (ribonucleotide reductase) and ubiquitin (van Strien et al, 1992(van Strien et al, , 1997Zuidema et al, 1993). The genetic organization of the SeMNPV genome appeared to differ considerably from that of AcMNPV and OpMNPV (van Strien, 1997 ;Ayres et al, 1994 ;Ahrens et al, 1997).…”

Identification and functional analysis of a non-hr origin of DNA replication in the genome of Spodoptera exigua multicapsid nucleopolyhedrovirus.

“…A detailed physical map has recently been constructed (Heldens et al, 1996 b) and a few genes, e.g. coding for polyhedrin (van Strien et al, 1992), p10 (Zuidema et al, 1993) andubiquitin (van Strien et al, 1996), have been identified and characterized. Information about the identity and genetic location of cis-and trans-acting factors involved in the replication of SeMNPV DNA is lacking.…”

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“…Further upstream, at position -230 and -251 nt, two characteristic early gene mRNA start sites (CAGT) were identified [27]. However, these putative start sites were not preceded by perfect TATA boxes as described by [28]. Downstream of the p26 ORF, two possible poly-A motifs were present at positions 41 and 51 nt relative to the putative stop codon TAA.…”