title: Potential coexistence of both bacterial and eukaryotic small RNA biogenesis and functional related protein homologs in Archaea.
abstract: RNA silencing plays crucial roles in both bacteria and eukaryotes, yet its machinery appears to differ in these two kingdoms. A couple of Argonaute protein homologs have been reported in some archaeal species in recent years. As Argonaute protein is the key component of eukaryotic RNA silencing pathways, such findings suggested the possibility of existence of eukaryotic RNA silencing like pathways in Archaea, which present the life forms between prokaryotes and eukaryotes. To further explore such hypothesis, we systematically screened 71 fully sequenced archaeal genomes, and identified some proteins containing homologous regions to the functional domains of eukaryotic RNA silencing pathway key proteins. The phylogenetic relationships of these proteins were analyzed. The conserved functional amino acids between archaeal and eukaryotic Piwi domains suggested their functional similarity. Our results provide new clues to the evolution of RNA silencing pathways.
authors.affiliation: State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Microbiology Chinese Academy of Sciences, Beijing, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Xiuying
authors.initials: X
authors.lastname: Liu
authors.forename: Li
authors.initials: L
authors.lastname: Huang
authors.forename: Huishan
authors.initials: H
authors.lastname: Guo
authors.forename: Xiu-Jie
authors.initials: XJ
authors.lastname: Wang
mesh_terms: D019843:Archaeal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017124:Conserved Sequence; D056890:Eukaryota / Q000378:metabolism*; D019143:Evolution, Molecular; D023281:Genomics; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D020365:RNA Helicases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D012329:RNA, Bacterial / Q000096:biosynthesis* / Q000235:genetics*; D022661:RNA, Untranslated / Q000096:biosynthesis* / Q000235:genetics*; D016914:Ribonuclease H / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D043244:Ribonuclease III / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
chemical_list: D019843:Archaeal Proteins; D012329:RNA, Bacterial; D022661:RNA, Untranslated; D043244:Ribonuclease III; D016914:Ribonuclease H; C078856:ribonuclease HI; D020365:RNA Helicases