title: Not so pseudo: the evolutionary history of protein phosphatase 1 regulatory subunit 2 and related pseudogenes.
abstract: BACKGROUND
  Pseudogenes are traditionally considered "dead" genes, therefore lacking biological functions. This view has however been challenged during the last decade. This is the case of the Protein phosphatase 1 regulatory subunit 2 (PPP1R2) or inhibitor-2 gene family, for which several incomplete copies exist scattered throughout the genome.
  
  
  RESULTS
  In this study, the pseudogenization process of PPP1R2 was analyzed. Ten PPP1R2-related pseudogenes (PPP1R2P1-P10), highly similar to PPP1R2, were retrieved from the human genome assembly present in the databases. The phylogenetic analysis of mammalian PPP1R2 and related pseudogenes suggested that PPP1R2P7 and PPP1R2P9 retroposons appeared before the great mammalian radiation, while the remaining pseudogenes are primate-specific and retroposed at different times during Primate evolution. Although considered inactive, four of these pseudogenes seem to be transcribed and possibly possess biological functions. Given the role of PPP1R2 in sperm motility, the presence of these proteins was assessed in human sperm, and two PPP1R2-related proteins were detected, PPP1R2P3 and PPP1R2P9. Signatures of negative and positive selection were also detected in PPP1R2P9, further suggesting a role as a functional protein.
  
  
  CONCLUSIONS
  The results show that contrary to initial observations PPP1R2-related pseudogenes are not simple bystanders of the evolutionary process but may rather be at the origin of genes with novel functions.
authors.forename: Luís
authors.initials: L
authors.lastname: Korrodi-Gregório
authors.forename: Joana
authors.initials: J
authors.lastname: Abrantes
authors.forename: Thorsten
authors.initials: T
authors.lastname: Muller
authors.forename: José
authors.initials: J
authors.lastname: Melo-Ferreira
authors.forename: Katrin
authors.initials: K
authors.lastname: Marcus
authors.forename: Odete A B
authors.initials: OA
authors.lastname: da Cruz e Silva
authors.forename: Margarida
authors.initials: M
authors.lastname: Fardilha
authors.affiliation: CIBIO-UP, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, InBIO, Laboratório Associado, Campus Agrário de Vairão, Vairão, Portugal. pjesteves@cibio.up.pt.
authors.forename: Pedro J
authors.initials: PJ
authors.lastname: Esteves
mesh_terms: D000818:Animals; D019143:Evolution, Molecular; D016678:Genome; D015894:Genome, Human; D006801:Humans; D008297:Male; D008322:Mammals / Q000235:genetics; D010802:Phylogeny; D054645:Protein Phosphatase 1 / Q000235:genetics*; D011544:Pseudogenes; D018626:Retroelements; D013081:Sperm Motility
chemical_list: D018626:Retroelements; D054645:Protein Phosphatase 1