KBF1 (p50 NF-kappa B homodimer) acts as a repressor of H-2Kb gene expression in metastatic tumor cells.

Abstract

Downregulation of major histocompatibility complex class I expression is causally related to high malignancy and low immunogenicity of certain murine tumors. In this study, we have analyzed the roles of the nuclear factors KBF1/p50 and p65 in regulation of class I expression in high and low metastatic tumor cells. Low class I-expressing cells show at higher levels of KBF1/p50 and NF-kappa B (p50/p65) binding activity than high class I-expressing cells. However, an excess of KBF1 over NF-kappa B is observed in low expressing cells, while an excess of NF-kappa B over KBF1 is observed in high expressing cells. Stable transfection of a p65 expression vector into low class I-expressing cells activated H-2 transcription and cell surface expression, while stable transfection of p50 expression vector into high expressing cells suppressed H-2Kb transcription and cell surface expression. Our studies suggest that KBF1 has the potential of downregulating class I gene expression, whereas dimers containing the p65 subunit are activators of class I gene expression.

• Authors: D Plaksin, P A Baeuerle, L Eisenbach
• Journal: The Journal of experimental medicine (J Exp Med) Vol. 177 Issue 6 Pg. 1651-62 (Jun 01 1993) ISSN: 0022-1007 [Print] United States
• PMID: 8496683 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• DNA-Binding Proteins
• H-2 Antigens
• H-2Kb protein, mouse
• NF-kappa B
• NF-kappa B p50 Subunit
• NFKB1 protein, human
• Repressor Proteins
• Transcription Factors

Topics

• Animals
• DNA-Binding Proteins (analysis)
• Enhancer Elements, Genetic
• Gene Expression Regulation, Neoplastic
• H-2 Antigens (genetics)
• Lung Neoplasms (genetics)
• Mice
• Mice, Inbred C57BL
• NF-kappa B (metabolism)
• NF-kappa B p50 Subunit
• Neoplasm Metastasis (genetics)
• Promoter Regions, Genetic
• Repressor Proteins (physiology)
• Transcription Factors (physiology)
• Tumor Cells, Cultured