Abundance of an endogenous retroviral envelope protein in placental trophoblasts suggests a biological function.
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.
Venables
P J
PJ
Kennedy Institute of Rheumatology, London, United Kingdom.
Brookes
S M
SM
Griffiths
D
D
Weiss
R A
RA
Boyd
M T
MT
D000595:Amino Acid Sequence; D001483:Base Sequence; D002478:Cells, Cultured; D017931:DNA Primers; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D008969:Molecular Sequence Data; D010920:Placenta / Q000166:cytology / Q000378:metabolism* / Q000821:virology; D012191:Retroviridae Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology; D014327:Trophoblasts / Q000378:metabolism* / Q000821:virology; D014759:Viral Envelope Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology
D017931:DNA Primers; D012191:Retroviridae Proteins; D014759:Viral Envelope Proteins