title: Ancient and recent selective pressures shaped genetic diversity at AIM2-like nucleic acid sensors.
abstract: AIM2-like receptors (ALRs) are a family of nucleic acid sensors essential for innate immune responses against viruses and bacteria. We performed an evolutionary analysis of ALR genes (MNDA, PYHIN1, IFI16, and AIM2) by analyzing inter- and intraspecies diversity. Maximum-likelihood analyses indicated that IFI16 and AIM2 evolved adaptively in primates, with branch-specific selection at the catarrhini lineage for IFI16. Application of a population genetics-phylogenetics approach also allowed identification of positive selection events in the human lineage. Positive selection in primates targeted sites located at the DNA-binding interface in both IFI16 and AIM2. In IFI16, several sites positively selected in primates and in the human lineage were located in the PYD domain, which is involved in protein-protein interaction and is bound by a human cytomegalovirus immune evasion protein. Finally, positive selection was found to target nuclear localization signals in IFI16 and the spacer region separating the two HIN domains. Population genetic analysis in humans revealed that an IFI16 genic region has been a target of long-standing balancing selection, possibly acting on two nonsynonymous polymorphisms located in the spacer region. Data herein indicate that ALRs have been repeatedly targeted by natural selection. The balancing selection region in IFI16 carries a variant with opposite risk effect for distinct autoimmune diseases, suggesting antagonistic pleiotropy. We propose that the underlying scenario is the result of an ancestral and still ongoing host-pathogen arms race and that the maintenance of susceptibility alleles for autoimmune diseases at IFI16 represents an evolutionary trade-off.
authors.affiliation: Bioinformatics Laboratory, Scientific Institute IRCCS E. Medea, Bosisio Parini (LC), Italy.
authors.forename: Rachele
authors.initials: R
authors.lastname: Cagliani
authors.forename: Diego
authors.initials: D
authors.lastname: Forni
authors.forename: Mara
authors.initials: M
authors.lastname: Biasin
authors.forename: Manuel
authors.initials: M
authors.lastname: Comabella
authors.forename: Franca R
authors.initials: FR
authors.lastname: Guerini
authors.forename: Stefania
authors.initials: S
authors.lastname: Riva
authors.forename: Uberto
authors.initials: U
authors.lastname: Pozzoli
authors.forename: Cristina
authors.initials: C
authors.lastname: Agliardi
authors.forename: Domenico
authors.initials: D
authors.lastname: Caputo
authors.forename: Sunny
authors.initials: S
authors.lastname: Malhotra
authors.forename: Xavier
authors.initials: X
authors.lastname: Montalban
authors.forename: Nereo
authors.initials: N
authors.lastname: Bresolin
authors.forename: Mario
authors.initials: M
authors.lastname: Clerici
authors.forename: Manuela
authors.initials: M
authors.lastname: Sironi
mesh_terms: D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D002522:Chlorocebus aethiops; D004268:DNA-Binding Proteins / Q000235:genetics*; D019143:Evolution, Molecular; D014644:Genetic Variation; D006071:Gorilla gorilla; D006801:Humans; D008252:Macaca fascicularis; D008969:Molecular Sequence Data; D002679:Pan troglodytes; D010802:Phylogeny; D011148:Pongo pygmaeus; D012641:Selection, Genetic
chemical_list: D004268:DNA-Binding Proteins
keywords: AIM2-like receptors; IFI16; long-standing balancing selection; positive selection