文章基本信息

标题：Expression and purification of the leucine zipper and DNA-binding domains of Fos and Jun: both Fos and Jun contact DNA directly.
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作者：C Abate ; D Luk ; R Gentz 等
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1990
卷号：87
期号：3
页码：1032-1036
DOI：10.1073/pnas.87.3.1032
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The protein products of the fos and jun protooncogenes interact cooperatively in the form of a heterodimer with the activator protein 1 (AP-1) regulatory element. To characterize the properties of these proteins, we have expressed polypeptides comprised of the dimerization and DNA-binding domains of Fos and Jun in Escherichia coli. The mini-Fos (wbFos) and the mini-Jun (wbJun) proteins were purified to apparent homogeneity by using a nickel affinity chromatography procedure. Purified wbFos and wbJun associated rapidly in vitro and interacted cooperatively with the human metallothionein IIA AP-1-binding site. However, efficient DNA binding of wbJun and wbFos-wbJun complexes required an additional activity present in nuclear extracts. This activity was sensitive to alkylating agents and could be partially mimicked by the presence of reducing and stabilizing agents. DNase I footprinting experiments demonstrated that Jun homodimeric complexes and Fos-Jun heterodimeric complexes interacted with the same site on the human metallothionein IIA gene. Moreover, UV-crosslinking studies demonstrated that Fos and Jun contact DNA directly and that both proteins interacted equivalently with either strand of the AP-1-binding site.