Regulation of Classical HLA Class I Genes in Human Choriocarcinoma Cells by Nuclear Proteins Binding to MHC Class I Regulatory Elements


Department of Obstetrics and Gynecology, Osaka University Medical School, 2-2 Yamadaoka, Suita, 565, Japan.


PROBLEM: The regulation of classical HLA class I genes in choriocarcinoma have been reported.

METHODS: We determined whether four choriocarcinoma cell lines expressed classical HLA class I or HLA-G by a reverse transcription-polymerase chain reaction (RT-PCR) and studied the regulatory mechanism of classical class I using a gel mobility shift assay.

RESULTS: NUC1 and SCH expressed classical class I but not HLA-G. GCH1 and Jar did neither. Nuclear protein binding to the class I regulatory element (CRE) was detected in NUC1 and SCH. Interferon-γ augmented both classical class I expression and the DNA-protein complex in NUC1. The DNA-protein complex was not observed in GCH1, and Jar showed a CRE-binding protein with different electrophoretic mobility and binding affinity from that of SCH and NUC1.

CONCLUSION: The CRE is one of the regulatory elements of classical HLA class I genes in choriocarcinoma cells.