Redondoviridae

Redondoviruses are assigned by the International Committee on Taxonomy of Viruses (ICTV) to the Redondoviridae.{{cite web |title=ICTV Report Redondoviridae |url=http://www.ictv.global/report/redondoviridae}}{{cite web |last1=Abbas |first1=AA |last2=Taylor |first2=LJ |last3=Collman |first3=RG |last4=Bushman |first4=Frederic D. |title=Create one new family (Redondoviridae) for circular, Rep-encoding DNA viruses |url=https://ictv.global/ictv/proposals/2019.011D.zip |format=docx |website=ictv.global |publisher=International Committee on Taxonomy of Viruses |language=en |date=14 October 2019 |access-date=31 January 2025}}

The family Redondoviridae contains one genus, Torbevirus, which contains two species, Brisavirus (Torbevirus brisa) and Vientovirus (Torbevirus viento). The names derive from the words for breeze and wind in Spanish (“{{lang|es|brisa}}” and “{{lang|es|viento}}”), denoting the association with the human airway. Multiple strains have been proposed on the basis of viral genome structure.{{cn|date=November 2022}}

The redondoviruses are members of the Circular Rep-Containing Single Stranded (CRESS) DNA Virus group.{{Citation|last1=Zhao|first1=Lele|title=Eukaryotic Circular Rep-Encoding Single-Stranded DNA (CRESS DNA) Viruses: Ubiquitous Viruses With Small Genomes and a Diverse Host Range|date=2019|journal=Advances in Virus Research|volume=103|pages=71–133|publisher=Elsevier|language=en|doi=10.1016/bs.aivir.2018.10.001|pmid=30635078|isbn=978-0-12-817722-8|last2=Rosario|first2=Karyna|last3=Breitbart|first3=Mya|last4=Duffy|first4=Siobain|s2cid=58636379 }}

•  Phylum: Cressdnaviricota{{Cite web|url=https://talk.ictvonline.org/files/proposals/animal_dna_viruses_and_retroviruses/m/animal_dna_ec_approved/9355|archive-url=https://web.archive.org/web/20200212184351/https://talk.ictvonline.org/files/proposals/animal_dna_viruses_and_retroviruses/m/animal_dna_ec_approved/9355|url-status=dead|archive-date=February 12, 2020|title=Create 1 new phylum (Cressdnaviricota) including 2 classes and 6 orders for classification of CRESS-DNA viruses.|last=Krupovic M, Varsani A, Kuhn J, Kazlauskas D, Breitbart M, Delwart E, Rosario K, Yutin N, Wolf YI, Harrach B, Zerbini FM, Dolja VV, Koonin EV|date=2019|website=ICTV Taxonomy Proposal 2019.012D.A.v1.Cressdnaviricota}}
•  Class: Arfiviricetes (Ar from arginine; fi from finger; describes a feature of the Rep protein conserved among viruses in this class)
•  Order: Recrevirales{{cite web|url=https://ictv.global/taxonomy/taxondetails?taxnode_id=202307362&taxon_name=Redondoviridae|title=History of the taxon: Family: Redondoviridae (2023 Release, MSL #39)|author=|date=|website=ictv.global|publisher=International Committee on Taxonomy of Viruses|access-date=31 January 2025|quote=}} (Re from redondoviruses; cre from CRESS)

The redondovirus genome is circular, and by analogy to other CRESS viruses likely single stranded. Genomes range in size from about 3.0 to 3.1 kilobases. The genome encodes three inferred proteins:{{cn|date=November 2022}}

• A Rep protein that likely initiates rolling-circle DNA replication.
• A Cap protein that likely self-assembles to yield icosahedral particles.
• An ORF3 protein of unknown function. ORF3 is entirely encoded within the Cap coding region in a different reading frame.

Redondovirus genomes have been reported primarily from human samples surveyed using metagenomic DNA sequencing. They have been found primarily in oral and airway specimens.In some human populations, oral samples can show up to 80% Redondovirus positivity.{{cite journal |vauthors=Taylor LJ, Dothard MI, Rubel MA, Allen AA, Hwang Y, Roche AM, Graham-Wooten J, Fitzgerald AS, Khatib LA, Ranciaro A, Thompson SR, Beggs WR, Campbell MC, Mokone GG, Mpoloka SW, Fokunang C, Njamnshi AK, Mbunwe E, Woldemeskel D, Belay G, Nyambo T, Tishkoff SA, Collman RG, Bushman FD |title=Redondovirus Diversity and Evolution on Global, Individual, and Molecular Scales |journal=J Virol |volume=95 |issue=21 |pages=e0081721 |date=October 2021 |pmid=34406857 |pmc=8513488 |doi=10.1128/JVI.00817-21 |url=}}

Analysis of a variety of human-derived sample types showed a strong positive correlation of Redondovirus DNA and DNA of the oral amoeba Entamoeba gingivalis. Follow up studies showed that a xenic culture containing Entamoeba gingivalis and feeder bacteria was also positive for redondovirus DNA and RNA. Analysis using intracellular cross linking (Hi-C) showed crosslinking of redondovirus DNA to Entamoeba DNA, supporting Entamoeba gingivalis as the host.{{cite journal |last1=Keeler |first1=Emma |last2=Merenstein |first2=Carter |last3=Reddy |first3=Shantan |last4=Taylor |first4=Louis |last5=Cobian-Guemes |first5=Ana |last6=Zankharia |first6=Urvi |last7=Collman |first7=Ronald |last8=Bushman |first8=Frederic |title=Widespread, human-associated redondoviruses infect the commensal protozoan Entamoeba gingivalis |journal=Cell Host and Microbe |date=December 1, 2022 |volume=31 |issue=1 |pages=58–68.e5 |doi=10.1016/j.chom.2022.11.002 |pmid= 36459997|s2cid=254179614 |pmc=9969835 }}{{cite journal |last1=Kinsella |first1=Cormac |last2=Deijs |first2=Martin |last3=Becker |first3=Christin |last4=Broekhuizen |first4=Patricia |last5=van Gool |first5=Tom |last6=Bart |first6=Aldert |last7=Schaefer |first7=Arne |last8=van der Hoek |first8=Lia |title=Host prediction for disease-associated gastrointestinal cressdnaviruses |journal=Virus Evol. |date=September 16, 2022 |volume=8 |issue=2 |pages=veac087 |doi=10.1093/ve/veac087 |pmid=36325032|pmc=9615429 }}

It is unknown whether redondoviruses cause human disease. Some CRESS viruses are known pathogens, such as porcine circovirus type 2{{Cite journal|author-link1=Meng Xiang-Jin|last=Meng|first=Xiang-Jin|date=January 2013|title=Porcine Circovirus Type 2 (PCV2): Pathogenesis and Interaction with the Immune System|journal=Annual Review of Animal Biosciences|language=en|volume=1|issue=1|pages=43–64|doi=10.1146/annurev-animal-031412-103720|pmid=25387012|issn=2165-8102}}

Redondoviruses have been reported associated with periodontitis. In one study, the levels fell with successful treatment. Abundance of redondovirus genomes has also been found to be high in some intensive care unit patients, and in patients with severe COVID-19.{{cite journal |vauthors=Merenstein C, Liang G, Whiteside SA, Cobián-Güemes AG, Merlino MS, Taylor LJ, Glascock A, Bittinger K, Tanes C, Graham-Wooten J, Khatib LA, Fitzgerald AS, Reddy S, Baxter AE, Giles JR, Oldridge DA, Meyer NJ, Wherry EJ, McGinniss JE, Bushman FD, Collman RG |title=Signatures of COVID-19 Severity and Immune Response in the Respiratory Tract Microbiome |journal=mBio |volume=12 |issue=4 |pages=e0177721 |date=August 2021 |pmid=34399607 |pmc=8406335 |doi=10.1128/mBio.01777-21 |url=}} At present the basis of these disease associations is unclear.

{{Reflist|2}}

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• [http://www.ictv.global/report/redondoviridae ICTV Report: Redondoviridae]

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Category:DNA viruses

Category:Virus families