Snake deltavirus utilizes envelope proteins of different viruses to generate infectious particles

Abstract

2Hepatitis D virus (HDV) is the only known human satellite virus, and it requires hepatitis B virus 3 (HBV) to form infectious particles. Until 2018 HDV was the sole representative of the 4 genus Deltavirus. The subsequent identification of HDV-like agents in non-human hosts indicated a 5 much longer evolutionary history of deltaviruses than previously hypothesized. Interestingly, none 6 of the HDV-like agents were found in co-infection with an HBV-like agent suggesting that these 7 viruses use different helper virus(es). Here we show, using snake deltavirus (SDeV), that HBV 8

Identification of novel avian and mammalian deltaviruses provides new insights into deltavirus evolution

“…We first determined if the replication initiated by transfecting these plasmids. These plasmids express the minus-strand genome and therefore DAg protein is expressed if the viral genome replicates ( Szirovicza et al. 2020 ).…”

“…2020 ). Further, viral envelope proteins of reptarenavirus and hartmanivirus, but not HBV, confer infectivity upon the snake deltavirus ( Szirovicza et al. 2020 ).…”

Diversification of mammalian deltaviruses by host shifting

“…The lack of farnesylation sites in DrDVs raises further doubts that hepadnaviruses facilitate transmission. Given the growing body of evidence that deltaviruses can exploit diverse enveloped viruses (11,19), concurrent or sequential swapping of host species and helper viruses seems the most plausible explanation for deltavirus diversification. Our results therefore imply a swap in helper use along the evolutionary divergence separating human and vampire bat-infecting deltaviruses, though the current helper(s) that facilitate transmission among bats remain a mystery.…”

“…Replication of DrDV in human cells would be unsurprising given the ability of the more divergent snake deltavirus to do so (19). Moreover, HDV infects woodchucks (a rodent) experimentally, suggesting that deltaviruses generally may have a broad cellular tropism (5).…”

“…Specifically, given the broad cellular tropism of deltaviruses, satellite-helper interactions would likely be more important determinants of cross-species transmission than satellite-host interactions (11,19). Consequently, anticipating host shifts would require understanding the determinants of satellite and helper virus compatibility along with prevalence and diversity of compatible helpers in candidate hosts, rather than classical barriers such as host cell receptor use or evasion of innate immunity.…”