title: A self-encoded capsid derivative restricts Ty1 retrotransposition in Saccharomyces.
abstract: Retrotransposons and retroviral insertions have molded the genomes of many eukaryotes. Since retroelements transpose via an RNA intermediate, the additive nature of the replication cycle can result in massive increases in copy number if left unchecked. Host organisms have countered with several defense systems, including domestication of retroelement genes that now act as restriction factors to minimize propagation. We discovered a novel truncated form of the Saccharomyces Ty1 retrotransposon capsid protein, dubbed p22 that inhibits virus-like particle (VLP) assembly and function. The p22 restriction factor expands the repertoire of defense proteins targeting the capsid and highlights a novel host-parasite strategy. Instead of inhibiting all transposition by domesticating the restriction gene as a distinct locus, Ty1 and budding yeast may have coevolved a relationship that allows high levels of transposition when Ty1 copy numbers are low and progressively less transposition as copy numbers rise. Here, we offer a perspective on p22 restriction, including its mode of expression, effect on VLP functions, interactions with its target, properties as a nucleic acid chaperone, similarities to other restriction factors, and future directions.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, 30602, USA. djgarf@bmb.uga.edu.
authors.forename: David J
authors.identifier: http://orcid.org/0000-0001-6234-2426
authors.initials: DJ
authors.lastname: Garfinkel
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, 30602, USA.
authors.forename: Jessica M
authors.initials: JM
authors.lastname: Tucker
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, 30602, USA.
authors.forename: Agniva
authors.initials: A
authors.lastname: Saha
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, 30602, USA.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Nishida
authors.affiliation: Department of Structural Chemistry and Biology of Nucleic Acids, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Pachulska-Wieczorek
authors.affiliation: Institute of Computing Science, Poznan University of Technology, Poznan, Poland.
authors.forename: Leszek
authors.initials: L
authors.lastname: Błaszczyk
authors.affiliation: Department of Structural Chemistry and Biology of Nucleic Acids, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland.
authors.forename: Katarzyna J
authors.initials: KJ
authors.lastname: Purzycka
mesh_terms: D000818:Animals; D002213:Capsid / Q000378:metabolism; D018628:Gene Dosage; D015966:Gene Expression Regulation, Fungal; D006801:Humans; D018626:Retroelements; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism
chemical_list: D018626:Retroelements
keywords: Gag; Nucleic acid chaperone; RNA; Restriction factor; Retrotransposon; Saccharomyces; VLP assembly