Nucleic Acids Res. 2015 Apr 20;43(7):3701-11. doi:10.1093/nar/gkv169

Henriet S, Sumic S, Doufoundou-Guilengui C, Jensen MF, Grandmougin C, Fal K, Thompson E, Volff JN, Chourrout D.

Embryonic expression of endogenous retroviral RNAs in somatic tissues adjacent to the Oikopleura germline.

“In several Tor elements, env expression is driven by an internal promoter and not by the 5′LTR.” “Using human HEK293T cells, [...] Env was associated with cell membranes during subcellular fractionation.” “Some Tor elements are active and have recently integrated copies in Oikopleura germline DNA.” “Comparison of Argonaute protein sequences in the Oikopleura genome identified a single Piwi, sharing diagnostic residues with fly and vertebrate Piwi.” ”Our results show that expression of Tor in somatic tissues was located in proximity to germ cells. Tor RNA seemed mostly absent from germ cells themselves.”