POLYDNAVIRUS GENES AND GENOMES: Emerging Gene Families and New Insights into Polydnavirus Replication

Abstract

Polydnavirus genome sequencing is providing new insights into viral genome organization and viral gene function. Sequence analyses demonstrate that the genomes of these viral mutualists are largely noncoding but maintain genes and gene families that are unrelated to other viral genes. Interestingly, these organizational patterns in polydnavirus genomes are evident in both the bracovirus and ichnovirus genera, even though these two genera are evolutionarily unrelated. The identity and function of some polydnavirus gene families are considered with some functions experimentally supported and others implied by homology relationships with known insect genes. The evidence relative to polydnavirus origins and evolution is considered but remains an area of speculation. However, sequencing of these viral genomes has been informative and provides opportunities for productive investigation of these unusual mutualistic insect viruses.

Functional endogenous viral elements in the genome of the parasitoid wasp Cotesia congregata : insights into the evolutionary dynamics of bracoviruses

“…According to this hypothesis, adjacent segments in the same orientation and separated by small spacers could fail to be resolved (figure 1a, blue lines). We were indeed able to observe this phenomenon resulting in large circles containing the sequences of two segments in the particles, a situation similar to circle 'nesting' observed in ichnoviruses [44]. Given that the length of BV nucleocapsids is correlated with the size of the dsDNA molecule they contain [36,37], a large range of DNA circle sizes can be encapsidated thus allowing nesting.…”

A SERI technique reveals an immunosuppressive activity of a serine-rich protein encoded in Cotesia plutellae bracovirus

“…PDVs harbor large multigene families that are often implicated in immunosuppression and immunoevasion in parasitized hosts (17). CpBV is regarded as a major factor in reducing cellular immune capacity in parasitized P. xylostella (18,19).…”

Involvement of Gap Junction Proteins in Infectious Diseases Caused by Parasites

“…Usually, Inx genes are encoded on multiple exons and have the potential to produce more than one protein by differential splicing [18]. Recently, viral homologs of Panxs/Inxs were identified in Polydnaviruses and denominated vinnexins (Vinx) [19]. …”