Expression of HLA class II-associated peptide transporter and proteasome genes in human placentas and trophoblast cell lines.
Expression of HLA class I antigens is closely controlled in the placental trophoblast cells, which interface directly with maternal cells during pregnancy. In this study, the possibility that peptide transporter (TAP-1, TAP-2) or proteasome (LMP7) genes might be involved in regulating antigen expression in these or other cells that comprise placentas was investigated. Analysis by Northern blot hybridization showed that transcripts from all three genes were present in samples of first trimester and term placental RNA. TAP-1 and TAP-2 messages were consistently more abundant in early than in late gestation placentas, whereas the reverse was observed for LMP7 mRNA. Futher experiments were done on two trophoblast cell lines. One line, Jar, is negative for HLA class I, and the second, JEG-3, expresses HLA-G as well as other HLA class I genes. Both Jar and JEG-3 cells contained TAP-1, TAP-2 and LMP7 mRNA. With the exception of LMP7 in JEG-3 cells, message from all three genes was increased by treating the trophoblast cells with interferon-gamma. While no evidence was collected to support the postulate that the HLA class I negative status of some trophoblast cell subpopulations could be related to absent or dysfunctional TAP-1, TAP-2 or LMP7 mRNA, the data are consistent with the postulate that placental cell expression of HLA class I antigens could be influenced by the availability of peptide transporters and proteasome components.
Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City 66160-7400.
K F
KF
Roby
K
K
Fei
Y
Y
Yang
J S
JS
Hunt
D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D000071450:ATP Binding Cassette Transporter, Subfamily B, Member 3; D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D001692:Biological Transport; D015152:Blotting, Northern; D002352:Carrier Proteins / Q000235:genetics*; D002460:Cell Line; D003546:Cysteine Endopeptidases; D005260:Female; D015870:Gene Expression; D005802:Genes, MHC Class II; D006801:Humans; D009097:Multienzyme Complexes; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011263:Pregnancy Trimester, Third; D046988:Proteasome Endopeptidase Complex; D011506:Proteins / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D014327:Trophoblasts / Q000378:metabolism*
D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D000071450:ATP Binding Cassette Transporter, Subfamily B, Member 3; D018528:ATP-Binding Cassette Transporters; D002352:Carrier Proteins; D009097:Multienzyme Complexes; D011506:Proteins; D012333:RNA, Messenger; C073119:TAP1 protein, human; C071692:TAP2 protein, human; D003546:Cysteine Endopeptidases; C077436:LMP7 protein; D046988:Proteasome Endopeptidase Complex