title: DNA-guided DNA interference by a prokaryotic Argonaute.
abstract: RNA interference is widely distributed in eukaryotes and has a variety of functions, including antiviral defence and gene regulation. All RNA interference pathways use small single-stranded RNA (ssRNA) molecules that guide proteins of the Argonaute (Ago) family to complementary ssRNA targets: RNA-guided RNA interference. The role of prokaryotic Ago variants has remained elusive, although bioinformatics analysis has suggested their involvement in host defence. Here we demonstrate that Ago of the bacterium Thermus thermophilus (TtAgo) acts as a barrier for the uptake and propagation of foreign DNA. In vivo, TtAgo is loaded with 5'-phosphorylated DNA guides, 13-25 nucleotides in length, that are mostly plasmid derived and have a strong bias for a 5'-end deoxycytidine. These small interfering DNAs guide TtAgo to cleave complementary DNA strands. Hence, despite structural homology to its eukaryotic counterparts, TtAgo functions in host defence by DNA-guided DNA interference.
authors: Laboratory of Microbiology, Department of Agrotechnology and Food Sciences, Wageningen University, Dreijenplein 10, 6703 HB Wageningen, the Netherlands.
authors: Daan C
authors: DC
authors: Swarts
authors: Laboratory of Microbiology, Department of Agrotechnology and Food Sciences, Wageningen University, Dreijenplein 10, 6703 HB Wageningen, the Netherlands.
authors: Matthijs M
authors: MM
authors: Jore
authors: Laboratory of Microbiology, Department of Agrotechnology and Food Sciences, Wageningen University, Dreijenplein 10, 6703 HB Wageningen, the Netherlands.
authors: Edze R
authors: ER
authors: Westra
authors: Laboratory of Microbiology, Department of Agrotechnology and Food Sciences, Wageningen University, Dreijenplein 10, 6703 HB Wageningen, the Netherlands.
authors: Yifan
authors: Y
authors: Zhu
authors: Laboratory of Microbiology, Department of Agrotechnology and Food Sciences, Wageningen University, Dreijenplein 10, 6703 HB Wageningen, the Netherlands.
authors: Jorijn H
authors: JH
authors: Janssen
authors: Clare Hall Laboratories, Cancer Research UK, London Research Institute, South Mimms EN6 3LD, UK.
authors: Ambrosius P
authors: AP
authors: Snijders
authors: Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
authors: Yanli
authors: Y
authors: Wang
authors: Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10065, USA.
authors: Dinshaw J
authors: DJ
authors: Patel
authors: Centro de Biología Molecular Severo Ochoa, UAM-CSIC, Campus de Cantoblanco, 28049 Madrid, Spain.
authors: José
authors: J
authors: Berenguer
authors: Laboratory of Microbiology, Department of Agrotechnology and Food Sciences, Wageningen University, Dreijenplein 10, 6703 HB Wageningen, the Netherlands.
authors: Stan J J
authors: SJJ
authors: Brouns
authors: Laboratory of Microbiology, Department of Agrotechnology and Food Sciences, Wageningen University, Dreijenplein 10, 6703 HB Wageningen, the Netherlands.
authors: John
authors: J
authors: van der Oost
mesh_terms: D060565:Argonaute Proteins / Q000378:metabolism*; D020029:Base Pairing / Q000235:genetics; D001483:Base Sequence; D004247:DNA / Q000235:genetics / Q000378:metabolism*; D053837:DNA Cleavage; D003841:Deoxycytidine / Q000235:genetics / Q000378:metabolism; D020868:Gene Silencing; D010766:Phosphorylation; D010957:Plasmids / Q000235:genetics; D011387:Prokaryotic Cells / Q000378:metabolism*; D016963:Thermus thermophilus / Q000235:genetics* / Q000378:metabolism*
chemical_list: D060565:Argonaute Proteins; D003841:Deoxycytidine; D004247:DNA