ERVW-1

ERVW-1 encodes Syncytin-1, a transmembrane glycoprotein also known as Env-W or HERV-W Env. Originating from an endogenous retrovirus, it mediates trophoblast syncytialization—the fusion of cytotrophoblast cells into syncytiotrophoblast, a critical process for placental development, nutrient exchange, and progesterone secretion during pregnancy. Its functional receptor is the neutral amino acid transporter ASCT2 (SLC1A5).
Dysregulated Syncytin-1 expression links to preeclampsia (impaired placental fusion) and multiple sclerosis (MS, via immune activation or demyelination). Preclinical research explores inhibitors like anti-Syncytin-1 monoclonal antibodies or ASCT2 antagonists for MS and pregnancy complications, though no targeted drugs are yet approved.