Expression of the human endogenous retrovirus HTDV/HERV-K is enhanced by cellular transcription factor YY1.
The human endogenous retrovirus HTDV/HERV-K, which resides in moderate copy numbers in the human genome, is expressed in a cell-type-specific manner, predominantly in teratocarcinoma cells. We have analyzed the regulatory potential of the 5' enhancer of the HERV-K long terminal repeat. Protein extracts of HERV-K-expressing teratocarcinoma cell lines (GH and Tera2) and nonexpressing HeLa and HepG2 cells form different protein complexes on the enhancer sequence as detected by electrophoretic mobility shift assays (EMSA). Using competition EMSAs, DNase I footprinting, and supershift experiments, we localized the binding site of these complexes to a 20-bp sequence within the enhancer and showed that the transcription factor YY1 is one component of the HERV-K enhancer complex. Replacement of the YY1 binding site with unrelated sequences reduced expression of the luciferase gene as a reporter in transient-transfection assays.
Knössl
M
M
Virology Department, Paul-Ehrlich-Institut, D-63225 Langen, Germany.
Löwer
R
R
Löwer
J
J
D004268:DNA-Binding Proteins / Q000378:metabolism*; D020077:Endogenous Retroviruses / Q000235:genetics*; D004742:Enhancer Elements, Genetic; D050981:Erythroid-Specific DNA-Binding Factors; D015967:Gene Expression Regulation, Viral; D006367:HeLa Cells; D006801:Humans; D014157:Transcription Factors / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D050986:YY1 Transcription Factor
D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D014157:Transcription Factors; D050986:YY1 Transcription Factor; C494698:YY1 protein, human