Sequence analysis of a non-classified, non-occluded DNA virus that causes salivary gland hypertrophy of Musca domestica, MdSGHV

Abstract

The genome of the virus that causes salivary gland hypertrophy in Musca domestica (MdSGHV) was sequenced. This non-classified, enveloped, double stranded, circular DNA virus had a 124,279bp genome. The G + C content was 43.5% with 108 putative methionine-initiated open reading frames (ORFs). Thirty ORFs had homology to database proteins: eleven to proteins coded by both baculoviruses and nudiviruses (p74, pif-1, pif-2, pif-3, odv-e66, rr1, rr2, iap, dUTPase, MMP, and Ac81-like), seven to nudiviruses (mcp, dhfr, ts, tk and three unknown proteins), one to baculovirus (Ac150-like), one to herpesvirus (dna pol), and ten to cellular proteins. Mass spectrum analysis of the viral particles' protein components identified 29 structural ORFs, with only p74 and odv-e66 previously characterized as baculovirus structural proteins. Although most of the homology observed was to nudiviruses, phylogenetic analysis showed that MdSGHV was not closely related to them or to the baculoviruses.

Nudivirus Genomics and Phylogeny

“…Besides in nudiviruses, homologues to baculovirus core genes were also detected in two salivary gland hypertrophy viruses (SGHVs) MdSGHV infecting the house fly Musca domestica and GpSGHV infecting the tsetse fly Glossina pallidipes (Abd-Alla et al 2008, Garcia-Maruniak et al 2008. GpSGHV and MdSGHV share 37 homologous ORFs and are phylogenetically closely related (Garcia-Maruniak et al 2009).…”

Analysis of transcripts from predicted open reading frames of Musca domestica salivary gland hypertrophy virus

“…Examination of sequencing chromatograms showed one or more possible terminations for most of the transcripts. A library of sequencing files of the trimmed 39-RACE sequences and each of the 108 putative ORF sequences described for MdSGHV (Garcia-Maruniak et al, 2008) was generated using the EditSeq program (DNASTAR, Lasergene), and sequences were aligned along with the complete MdSGHV genome sequence to detect the 39-UTR of each transcript. Each 39-RACE sequence was opened with Artemis v. 10 software (Rutherford et al, 2000).…”

“…The presence of overlapping ORFs in the MdSGHV genome may in part reflect the close proximity of the putative ORFs (Garcia-Maruniak et al, 2008). Historically, gene overlap, or 'overprinting', was thought to be a mechanism for maximizing the coding information within genomes of limited size (Fukuda et al, 2003;Lamb & Horvath, 1991).…”

“…The MdSGHV genome is 124 279 bp long and has a total of 108 putative ORFs (Garcia-Maruniak et al, 2008). Comparative analysis of the genome sequences has shown that the MdSGHV is closely related to the tsetse fly virus, Glossina pallidipes SGHV (GpSGHV): both SGHVs form a monophyletic clade distinct from other circular dsDNA insect viruses (Garcia-Maruniak et al, 2009).…”

“…Significantly, MdSGHV is capable of pervasive development in adult salivary glands; 100 % of the glands display SGH and release copious levels of infectious virus between 48 and 72 h post-injection (V. U. Lietze & D. G. Boucias, unpublished results). The synchronized infection displayed by this virus and the access to virus-free house fly colonies provides an inexpensive model to elucidate the in vivo biology of this dsDNA animal virus.The MdSGHV genome is 124 279 bp long and has a total of 108 putative ORFs (Garcia-Maruniak et al, 2008). Comparative analysis of the genome sequences has shown that the MdSGHV is closely related to the tsetse fly virus, Glossina pallidipes SGHV (GpSGHV): both SGHVs form a monophyletic clade distinct from other circular dsDNA insect viruses (Garcia-Maruniak et al, 2009).…”