Search for a human homologue of the mouse Ped gene.
The Ped gene influences the rate of cleavage division of preimplantation mouse embryos and subsequent embryonic survival. The mouse Ped gene product is a major histocompatibility complex (MHC) class Ib protein called Qa-2. Studies from many human in-vitro fertilization (IVF) clinics suggest that the mouse Ped gene has a human homologue because embryos fertilized at the same time have different cleavage rates, and those embryos that cleave at a faster rate are more likely to result in a viable pregnancy. Candidates for the human homologue of the mouse Ped gene include the MHC class Ib genes HLA-E, HLA-F, and HLA-G. The presence of mRNA for these three genes was tested in 108 spare day 3 human preimplantation embryos from 25 couples by using reverse transcription-polymerase chain reaction (RT-PCR). Of the 86 embryos tested for HLA-E mRNA, 72 were positive (84%), and of the 88 embryos tested for HLA-G mRNA, 39 were positive (44%). None of the 17 embryos tested for HLA-F mRNA were positive (0%). Studies of expression of HLA-G protein were undertaken to ascertain whether HLA-G was attached to the cell membrane via a glycosylphosphatidylinositol (GPI) linkage similar to that found in Qa-2 protein. Treatment of JEG-3 cells, an HLA-G expressing cell line, with phospholipase C did not result in removal of HLA-G showing that HLA-G, unlike Qa-2, is not GPI linked to the cell surface. The pros and cons of HLA-E, HLA-F, and HLA-G as candidates for the human Ped gene are discussed.
Cao
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Department of Biology, 414 Mugar Hall, Northeastern University, Boston, MA 02115, USA.
Brenner
C A
CA
Alikani
M
M
Cohen
J
J
Warner
C M
CM
D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D004622:Embryo, Mammalian; D047108:Embryonic Development / Q000235:genetics*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D017261:Glycosylphosphatidylinositols / Q000737:chemistry / Q000378:metabolism; D006680:HLA Antigens / Q000235:genetics* / Q000378:metabolism; D015395:Histocompatibility Antigens Class I / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D010716:Phosphatidylinositols / Q000494:pharmacology; D011247:Pregnancy; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014327:Trophoblasts / Q000187:drug effects / Q000378:metabolism; D010738:Type C Phospholipases / Q000494:pharmacology; D000097625:HLA-E Antigens
D017261:Glycosylphosphatidylinositols; D006680:HLA Antigens; D015395:Histocompatibility Antigens Class I; D010716:Phosphatidylinositols; D010738:Type C Phospholipases; D000097625:HLA-E Antigens; C062341:HLA-F antigens; C032907:Q surface antigens