Drosophila errantiviruses

Abstract

Retroelements with long-terminal repeats (LTRs) inhabit nearly all eukaryotic genomes. During the time of their rich evolutionary history they have developed highly diverse forms, ranging from ordinary retrotransposons to complex pathogenic retroviruses such as HIV-I. Errantiviruses are a group of insect endogenous LTR elements that share structural and functional features with vertebrate endogenous retroviruses. The errantiviruses illustrate one of the evolutionary strategies of retrotransposons to become infective, which together with their similarities to vertebrate retroviruses make them an attractive object of research promising to shed more light on the evolution of retroviruses.

Figure 1.

Evolutionary pathways that can lead to the origin of endogenous retroviruses. (A) Strategy that leads to formation of the most vertebrate endogenous retroviruses. In this case infectious retrovirus is loosing its infectivity, enters the germline and transfers vertically. (B) Aquisition of the env gene—a mechanism, by which errantiviruses gained the properties of endogenous retroviruses.