Endogenous retroviral envelope protein HEMO (ERVMER34-1)

Endogenous retroviral envelope protein HEMO (ERVMER34-1) is a membrane and secreted protein encoded by a captured retroviral envelope gene, the oldest full-length endogenous envelope gene in the human genome. It is primarily expressed in the placenta, stem cells, and is notably activated in a broad array of solid tumors, suggesting significant promise as a cancer biomarker and possible therapeutic target. HEMO’s expression is driven by a cellular CpG island rather than the original viral promoter, and increased levels in cancer may be regulated by the Wnt/β-catenin pathway. Functionally, while the ancestral protein mediates membrane fusion and receptor recognition during viral infection, the endogenous HEMO protein’s roles in human biology are not fully understood—some evidence points to immunomodulatory activity. To date, there are no approved drugs targeting ERVMER34-1, and its therapeutic exploitation will require careful tissue specificity evaluation, especially to avoid adverse effects in the kidney where it maintains basal expression.

Other names

Endogenous retrovirus group MER34 member 1, envelopeERVMER34-1Endogenous retroviral envelope protein HEMOEndogenous retroviral envelope protein HEMO, secreted formenvMER34Endogenous retrovirus group MER34 member 1 Env polyproteinHERV-MER_4q12 provirus ancestral Env polyproteinHuman endogenous MER34 (medium-reiteration-frequency-family-34) open reading frameHuman endogenous MER34 ORFHEMO, 48 kDa formLP9056 proteinMER34_HUMAN (UniProt)

Not applicable (no currently identified drugs targeting this molecule)