Abundance of an endogenous retroviral envelope protein in placental trophoblasts suggests a biological function

Virology. 1995 Aug 20;211(2):589-92. doi: 10.1006/viro.1995.1442.


To investigate the hypothesis that the human endogenous sequence ERV-3 has a function, we have cloned and expressed the transmembrane region of its envelope gene and raised specific antibodies to the fusion protein and to a synthetic peptide. These antibodies reacted with a 65-kDa polypeptide which constituted approximately 0.1% of the cellular protein in syncytiotrophoblasts in placenta. The evolutionary conservation and abundant expression of this endogenous retroviral protein in a specific cell type support the concept of a biological function. The similarity of a domain of ERV-3 env to putative immunosuppressive p15E sequences suggests that ERV-3 might form part of the placental immunosuppressive barrier between mother and foetus.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Cells, Cultured
  • DNA Primers
  • Female
  • Fluorescent Antibody Technique
  • Humans
  • Molecular Sequence Data
  • Placenta / cytology
  • Placenta / metabolism*
  • Placenta / virology
  • Retroviridae Proteins / biosynthesis*
  • Retroviridae Proteins / genetics
  • Retroviridae Proteins / physiology
  • Trophoblasts / metabolism*
  • Trophoblasts / virology
  • Viral Envelope Proteins / biosynthesis*
  • Viral Envelope Proteins / genetics
  • Viral Envelope Proteins / physiology


  • DNA Primers
  • Retroviridae Proteins
  • Viral Envelope Proteins