ERVWE 1 ( endogenous retroviral family W , Env ( C 7 ) , member 1 )

Hugo: ERVWE1 Other names: env; enverin; Env-W; HERV-W; HERV-W-ENV; HERV-W_7q21.2 provirus ancestral Env polyprotein precursor; HERV-7q; HERVW; Syncytin; Syncytin-1 Location: 7q21.2 Note: Sequences of retroviral origin represent about 8% of the human genome. There are at least 31 families of human endogenous retroviruses (HERVs). Each family derived from an independent infection of the germ line by an exogenous virus during the evolution of the human lineage. The infectious retrovirus founding the contemporary HERV-W family entered the human ancestor genome after the divergence between Catarrhini and Platyrrhini, i.e., less than 40 million years ago. The spread of the HERV-W family into the genome essentially results from events of intracellular retrotransposition of transcriptionally active copies, a phenomenon mediated either by their own reverse transcriptase (RT) machinery or by RT from LINE elements. Generally, due to the absence of a selective pressure, HERV-W elements have accumulated inactivating substitutions (frame-shifts, nonsense mutations), leading to complex multicopy families whose transmission is exclusively Mendelian. Thus, the contemporary HERV-W family consists of collections of heterogeneous elements, ranging from full-length defective proviruses (gag, pol, and env genes flanked at both extremities by two long terminal repeats (LTRs)) to isolated LTRs derived from recombination events. The human endogenous retrovirus HERV-W multicopy family includes a unique proviral locus, termed ERVWE1, which contains gag and pol pseudogenes and has retained a full-length envelope open reading frame (ORF) also named Syncytin or Syncytin-1. ERVWE1 is a bona fide gene involved in hominoid placental physiology.