title: Expansion of the Ago gene family in the teleost clade.
abstract: AGO proteins are universal effectors of eukaryotic small RNA-directed regulatory pathways. In this study, we used a comparative genomics approach to explore the AGO sub-family in the teleost clade. We identified five Ago homologues in teleost genomes, one more than encoded in other vertebrate clades. The additional teleost homologue was preserved most likely due to the differential retention of regulatory elements following the fish-specific genome duplication event that occurred approximately 350 million years ago. Analysis of all five Ago genomic loci in teleosts revealed that orthologues contain specific, conserved sequence elements in non-coding regions indicating that the teleost Ago paralogues are differentially regulated. This was supported by qRT-PCR analysis that showed differential expression of the zebrafish homologues across development and between adult tissues indicating stage and tissue-specific function of individual AGO proteins. Multiple sequence alignments showed not only that all teleost homologues possess critical residues for AGO function, but also that teleost homologues contain multiple orthologue-specific features, indicative of structural diversification. Notably, these are retained throughout the vertebrate lineage arguing these may be important for orthologue-specific functions.
authors.affiliation: Division of Molecular Genetics and Development, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia.
authors.forename: Lindsey
authors.initials: L
authors.lastname: McFarlane
authors.forename: Terje
authors.initials: T
authors.lastname: Svingen
authors.forename: Ingo
authors.initials: I
authors.lastname: Braasch
authors.forename: Peter
authors.initials: P
authors.lastname: Koopman
authors.forename: Manfred
authors.initials: M
authors.lastname: Schartl
authors.forename: Dagmar
authors.initials: D
authors.lastname: Wilhelm
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017124:Conserved Sequence; D015852:Eukaryotic Initiation Factor-2 / Q000145:classification* / Q000235:genetics*; D019143:Evolution, Molecular; D005399:Fishes / Q000235:genetics*; D020440:Gene Duplication; D016678:Genome; D008969:Molecular Sequence Data; D005810:Multigene Family; D009990:Oryzias / Q000235:genetics; D010802:Phylogeny; D058727:RNA, Small Untranslated / Q000235:genetics; D016415:Sequence Alignment; D023741:Takifugu / Q000235:genetics; D023721:Tetraodontiformes / Q000235:genetics; D015027:Zebrafish / Q000235:genetics
chemical_list: D015852:Eukaryotic Initiation Factor-2; D058727:RNA, Small Untranslated