Structure and evolutionary implications of a "cysteine-rich" Campoletis sonorensis polydnavirus gene family.

Abstract

For successful parasitization, the female Campoletis sonorensis endoparasitic wasp injects a polydnavirus into its host, Heliothis virescens, during oviposition. Viral gene expression induces immunosuppression and alters development of the host. We report here that three abundantly expressed genes, VHv1

Promoter analysis of a cysteine-rich Campoletis sonorensis polydnavirus gene.

“…Comparison of promoter regions of the cysteine-rich CsPDV genes shows greater identity between the putative TISs and start codons (Dib-Hajj et al, 1993). Analysis of the upstream promoter regions between the two subfamilies did not show significant identity, but within the subfamilies higher identities were observed (Fig.…”

“…5 a). About 200 bp of promoter region of the VHv1.1 gene (Dib-Hajj et al, 1993) was aligned with the VHv1.4 gene promoter, which showed 86 % identity (Fig. 5 b).…”

“…Members of the cysteine-rich PDV gene family are expressed only in parasitized lepidopteran larvae (Dib-Hajj et al, 1993 ;Cui & Webb, 1996). The early and host-specific expression of the cysteine-rich CsPDV genes suggests similarities in regulation.…”

“…Very early expression of the cysteine-rich CsPDV genes resembles that of the baculovirus immediate early genes. All the CsPDV cysteine-rich genes (WHv1.6, WHv1.0, VHv1.4 and VHv1.1) have TATA box motifs 25-35 nucleotides upstream of the transcription initiation site (TIS) (Blissard et al, 1987 ;Dib-Hajj et al, 1993 ;Cui & Webb, 1996). Preliminary gel retardation assays show binding of nuclear protein(s) to the region containing the TATA box (data not shown).…”

“…Five class II viral genes have been isolated, WHv1.6, 1.0, VHv1.1, 1.4 and BHv0.9 (Blissard et al, 1987 ;Theilmann & Summers, 1987 ;Dib-Hajj et al, 1993 ;Cui & Webb, 1996), which belong to two distinct gene families (Summers & Dib-Hajj, 1995). Four of these class II genes (WHv1.0, 1.6, VHv1.1, 1.4) have various degrees of identity to each other and constitute a cysteine-rich PDV gene family (Dib-Hajj et al, 1993 ;Cui & Webb, 1996). The BHv0.9 gene is a member of the repeat element (rep) gene family that contains a 540 bp repeat (Theilmann & Summers, 1987).…”