Halorubrum virus HRPV1
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Halorubrum pleomorphic virus 1 ( HRPV1 , officially Halorubrum virus HRPV1 ) is a species of single-stranded DNA virus in the virus family Pleolipoviridae . Its hosts are archaea of the genus Halorubrum from the class Halobacteria (Haloarchaeen), Phylum (division) Euryarchaeota . It was unlike any other virus known at the time of its discovery in that its genome is a single strand of DNA and it infects archaa. As with other archaeal viruses, the infection seemsto take placewithout final lysis (dissolution and destruction) of the host; the offspring viruses are likely toemerge from the cell membraneby budding .
construction
The virus particles (virions) are pleomorphic and have an outer lipid envelope . There are also two main structural proteins in the shell :
- VP3 - with 15 kDa (Kilo-Dalton)
- VP4 - with 53 kDa.
The genome does not appear to be associated with a nucleoprotein .
The spike protein (VP4) is glycosylated . Spike proteins are usually located in the outer shell of a virus particle and help the pathogen to penetrate the host cells. The lipid envelope of the virions is similar in composition to that of the host. VP3 is a membrane protein that is apparently not exposed to the external environment. It could be that it serves to form a kind of shell around the genome , as is the case with other viruses. However, so far this is only a guess.
Genome
The genome is a single-stranded DNA molecule 7048 bases in length . It encodes 9 open reading frames (ORFs). Two of them code for the structural proteins VP3 and VP4. Another encoded protein (VP8) appears to be an ATPase . The functions of the other proteins are not yet known.
Systematics
When comparing the reproduction cycle (penetration into the host and presumed leakage through budding), the structure of the virions (size of VP3 and VP4) and the genome, the great similarity with the Haloarcula virus HHPV1 (also called Haloarcula hispanica pleomorphic virus 1 ) is striking , although the latter has a double-stranded genome (Baltimore Group 1). This was the reason they were both assigned to the same genus Alphapleolipovirus in the family Pleolipoviridae . Confirmation of such a relationship for other viruses could indicate that the current Baltimore classification system needs to be revised.
Individual evidence
- ↑ a b c d e ICTV: ICTV Taxonomy history: Haloarcula virus HHPV1 , EC 51, Berlin, Germany, July 2019; Email ratification March 2020 (MSL # 35)
- ↑ a b ICTV : Master Species List 2018a v1 , MSL including all taxa updates since the 2017 release. Fall 2018 (MSL # 33)
- ↑ a b c d Pietila, M, Laurinavicius S, Sund, J, Roine E & Bamford D (2009) The single-stranded DNA genome of novel archaeal virus Halorubrum pleomorphic virus 1 Is enclosed in the envelope decorated with glycoprotein spikes. J Virol 84 (2) 788-798 doi : 10.1128 / JVI.01347-09
- ^ ICTV Online (10th) Report Pleolipoviridae .