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Updated: Aug 14, 2026

Single-molecule Imaging of Gene Regulation In vivo Using Cotranslational Activation by Cleavage (CoTrAC)
Published on: March 15, 2013
Direct cloning of leucine zipper proteins: Jun binds cooperatively to the CRE with CRE-BP1
P F Macgregor1, C Abate, T Curran
1Department of Molecular Oncology & Virology, Roche Institute of Molecular Biology, Nutley, New Jersey 07110.
Abstract:
The proto-oncogene products Fos and Jun form a stable heterodimeric complex that functions in transcriptional regulation by interacting with the DNA sequence known as the AP-1 site. Dimer formation occurs through the leucine zipper, a structural motif involving a heptad repeat of leucine residues that is conserved in several fos- and jun-related genes. We have employed a novel cloning strategy to isolate genes encoding proteins capable of forming complexes with Jun. The procedure involves direct screening of a lambda gt11 cDNA library with a biotinylated Jun polypeptide. One clone isolated in this manner encodes CRE-BP1, a leucine zipper-containing protein that binds to the cyclic AMP response element (CRE) as a homodimer. CRE-BP1 also forms heterodimers with Jun but not with Fos. Jun binds cooperatively to the CRE in association with CRE-BP1. Thus, the DNA-binding specificity and affinity of Jun are modulated by association with Fos or with CRE-BP1.
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