How might flukes and tapeworms maintain genome integrity without a canonical piRNA pathway?
Surveillance by RNA interference is central to controlling the mobilization of transposable elements (TEs). In stem cells, Piwi argonaute (Ago) proteins and associated proteins repress mobilization of TEs to maintain genome integrity. This defense mechanism targeting TEs is termed the Piwi-interacting RNA (piRNA) pathway. In this opinion article, we draw attention to the situation that the genomes of cestodes and trematodes have lost the piwi and vasa genes that are hallmark characters of the germline multipotency program. This absence of Piwi-like Agos and Vasa helicases prompts the question: how does the germline of these flatworms withstand mobilization of TEs? Here, we present an interpretation of mechanisms likely to defend the germline integrity of parasitic flatworms.
Department of Microbiology, Immunology, and Tropical Medicine, and Research Center for Neglected Tropical, Diseases School of Medicine and Health Sciences, George Washington University, Washington, DC 20037, USA.
Danielle E
DE
Skinner
Department of Microbiology, Immunology, and Tropical Medicine, and Research Center for Neglected Tropical, Diseases School of Medicine and Health Sciences, George Washington University, Washington, DC 20037, USA.
Gabriel
G
Rinaldi
Institute of Hygiene and Microbiology, University of Würzburg, Josef-Schneider-Strasse 2, Würzburg, D-97080, Germany; Sección Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de la República, Iguá 4225, CP 11400, Montevideo, Uruguay.
Uriel
U
Koziol
Institute of Hygiene and Microbiology, University of Würzburg, Josef-Schneider-Strasse 2, Würzburg, D-97080, Germany.
Klaus
K
Brehm
Department of Microbiology, Immunology, and Tropical Medicine, and Research Center for Neglected Tropical, Diseases School of Medicine and Health Sciences, George Washington University, Washington, DC 20037, USA. Electronic address: pbrindley@gwu.edu.
Paul J
PJ
Brindley
D000818:Animals; D060565:Argonaute Proteins / Q000235:genetics; D002589:Cestoda / Q000235:genetics*; D053487:DEAD-box RNA Helicases / Q000235:genetics / Q000378:metabolism; D042822:Genomic Instability / Q000235:genetics*; D010802:Phylogeny; D011499:Protein Processing, Post-Translational; D034741:RNA, Small Interfering / Q000235:genetics*; D014200:Trematoda / Q000235:genetics*
D060565:Argonaute Proteins; D034741:RNA, Small Interfering; D053487:DEAD-box RNA Helicases
Cestoda; Platyhelminthes; Trematoda; argonaute; germline; piRNA pathway; piwi; transposable elements; vasa