A transcription factor interacting with the class I gene enhancer is inactive in tumorigenic cell lines which suppress major histocompatibility complex class I genes.
AUTOR(ES)
Henseling, U
RESUMO
AKR leukemias display different amounts of major histocompatibility complex class I antigens on the cell surface. The absence of H-2Kk molecules correlates with the ability of these cell lines to form tumors in vivo as well as to escape lysis by cytotoxic T lymphocytes in vitro. In this report it is shown that the 5' regulatory area of the H-2Kk gene failed to activate transcription in H-2Kk-negative cells. Examination of the proteins interacting with the H-2Kk enhancer in expressing and nonexpressing cells revealed clear differences. In particular, the level of a nuclear protein interacting at position -166 was greatly reduced in the negative cell lines. A transcription factor, known as H2TF1 or KBF1, has been shown previously to interact with this binding site and to be essential for the expression of certain class I genes as well as the expression of beta 2-microglobulin. These results demonstrate that the molecular mechanism of class I gene suppression in malignant tumor cells is at the level of transcription and is most probably modulated by H2TF1/KBFI. In addition, it is shown that the same transcription factor is only present in mouse tissues expressing class I antigens.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=360928Documentos Relacionados
- A transcriptional enhancer and an interferon-responsive sequence in major histocompatibility complex class I genes.
- A second lineage of mammalian major histocompatibility complex class I genes.
- Transmembrane domain length variation in the evolution of major histocompatibility complex class I genes.
- An interferon gamma-regulated protein that binds the interferon-inducible enhancer element of major histocompatibility complex class I genes.
- Intron sequences reveal evolutionary relationships among major histocompatibility complex class I genes.