Soluble HLA-G molecule. An alternatively spliced HLA-G mRNA form candidate to encode it in peripheral blood mononuclear cells and human trophoblasts.
The HLA-G nonclassic MHC class I gene expressed at the maternal-fetal interface may be involved in cell protection against NK cell lysis. HLA-G mRNA is observed in different adult or fetal human cells and exhibits four alternative forms: HLA-G1, HLA-G2, HLA-G3, and HLA-G4 lacking, respectively, exon 7; exons 7 and 3, exons 7, 3, and 4; exons 7 and 4. Because exon 5 encodes the transmembrane domain of the HLA-G antigen, none of these transcripts could give a soluble form as detected in supernatant of trophoblasts. In this report, we describe an additional alternatively spliced for of HLA-G transcript (HLA-G5) present in adult PBMCs and first-trimester trophoblasts that contains intron 4. Moreover, as with all other transcripts, HLA-G5, is devoid of exon 7. Its relative frequency is, respectively, approximately 1:8 and approximately 1:26 in adult PBMCs and first-trimester trophoblasts. The presence of intron 4 generates a stop codon that excludes transmembrane region (exon 5) of the HLA-G molecule and therefore might produce a soluble antigen. These results are discussed with regard to data on soluble forms of classic HLA antigens and the possible role of HLA-G.
Moreau
P
P
CEA-DSV-DPTE, Laboratoire d'Immunoradiobiologie, Hôpital Saint-Louis, Paris, France.
Carosella
E
E
Teyssier
M
M
Prost
S
S
Gluckman
E
E
Dausset
J
J
Kirszenbaum
M
M
D017398:Alternative Splicing; D001483:Base Sequence; D018388:Codon, Terminator; D005333:Fetus / Q000276:immunology / Q000378:metabolism; D015870:Gene Expression; D006680:HLA Antigens / Q000096:biosynthesis / Q000235:genetics* / Q000276:immunology*; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I / Q000096:biosynthesis / Q000235:genetics* / Q000276:immunology*; D006801:Humans; D007438:Introns; D007963:Leukocytes, Mononuclear / Q000276:immunology* / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics*; D014327:Trophoblasts / Q000276:immunology* / Q000378:metabolism
D018388:Codon, Terminator; D006680:HLA Antigens; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I; D012333:RNA, Messenger