Abstract
Objective
To investigate the role of Sp1 as transcription factor required for transactivation of LRP16 gene by estrogen.
Methods
Specific antibodies of ERα and Sp1 were used to precipitate the target DNA/protein complexes of MCF-7 cells at different time points after estrogen treatment (Chromatin immunoprecipitation assay), the promoter region of LRP16 gene was amplified by semi-nested polymerase chain reaction (snPCR). Small interfering RNA (siRNA) against Sp1 was transiently contransfected with LRP16-Luc (containing the region from-213bp to-126bp of LRP16 gene promoter) in MCF-7 cells. The luciferase activities were measured by dual-luciferase assay.
Results
The results of chromatin immunoprecipitation assay showed that Sp1 protein directly bound to the-213bp to-126bp region of LRP16 gene, and ERα could enhance the affinity of Sp1 to DNA. Sp1-siRNA specifically decreased the transactivation of LRP16-Luc by 17β-estradiol to 70–80%.
Conclusion
The estrogen-induced transactivation of the human LRP16 gene was mediated by Sp1 protein. Moreover, the interactions of ERα/Sp1 functional complex with LRP16 promoter DNA were required for enhanced LRP16 gene transactivation.
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Foundation item: This work was supported by the National Natural Science Foundation of China (No.30572096) and Beijing Natural Science Foundation (No.5052024).
Biography: SI Yi-ling (1972–), female, doctor of medicine, assistant professor, PLA General Hospital, majors in molecular biology of tumor.
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Si, Yl., Han, Wd., Zhao, Yl. et al. Estrogen regulation of LRP16 gene expression involves Sp1 transcription factor. Chin. J. Cancer Res. 18, 251–256 (2006). https://doi.org/10.1007/s11670-006-0251-2
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DOI: https://doi.org/10.1007/s11670-006-0251-2