Viral particles of endogenous betaretroviruses are released in the sheep uterus and infect the conceptus trophectoderm in a transspecies embryo transfer model

Sarah Black (1, 2) , Frederick Arnaud (3) , Robert Burghardt (4) , Carey Satterfield (1, 2) , Jo-Ann Fleming (1, 2) , Charles Long (5) , Carol Hanna (5) , Lita Murphy (6) , Roman Biek (7) , Massimo Palmarini (6) , Thomas Spencer (1, 2)

1 Department of Animal Science
2 Center of Animal Biotechnology and Genome
3 RPC - Rétrovirus et Pathologie Comparée
4 Department of Veterinary Integrative Biosciences
5 Department of Veterinary Physiology and Pharmacology
6 Institute of Biodiversity, Animal Health and Comparative Medicine
7 Division of Ecology and Evolutionary Biology

The sheep genome contains multiple copies of endogenous betaretroviruses highly related to the exogenous and oncogenic jaagsiekte sheep retrovirus (JSRV). The endogenous JSRVs (enJSRVs) are abundantly expressed in the uterine luminal and glandular epithelia as well as in the conceptus trophectoderm and are essential for conceptus elongation and trophectoderm growth and development. Of note, enJSRVs are present in sheep and goats but not cattle. At least 5 of the 27 enJSRV loci cloned to date possess an intact genomic organization and are able to produce viral particles in vitro. In this study, we found that enJSRVs form viral particles that are released into the uterine lumen of sheep. In order to test the infectious potential of enJSRV particles in the uterus, we transferred bovine blastocysts into synchronized ovine recipients and allowed them to develop for 13 days. Analysis of microdissected trophectoderm of the bovine conceptuses revealed the presence of enJSRV RNA and, in some cases, DNA. Interestingly, we found that RNAs belonging to only the most recently integrated enJSRV loci were packaged into viral particles and transmitted to the trophectoderm. Collectively, these results support the hypothesis that intact enJSRV loci expressed in the uterine endometrial epithelia are shed into the uterine lumen and could potentially transduce the conceptus trophectoderm. The essential role played by enJSRVs in sheep reproductive biology could also be played by endometrium-derived viral particles that influence development and differentiation of the trophectoderm.

Mots clés: wether hoggs

Mots clés: particule virale; mouton; cellule trophoblastique; rétrovirus; utérus; transfert d'embryon

Domaines: Virologie

Sarah Black, Frederick Arnaud, Robert Burghardt, Carey Satterfield, Jo-Ann Fleming, et al.. Viral particles of endogenous betaretroviruses are released in the sheep uterus and infect the conceptus trophectoderm in a transspecies embryo transfer model. Journal of Virology, 2010, 84 (18), pp.9078-9085. ⟨10.1128/JVI.00950-10⟩. ⟨hal-01606951⟩