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fos and jun interaction: The role of the leucine zipper
Author(s) -
Ransone Lynn J.,
Visvader Jane,
Lamph William W.,
SassoneCorsi Paolo,
Verma Inder M.
Publication year - 1989
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.2910440705
Subject(s) - leucine zipper , bzip domain , basic helix loop helix leucine zipper transcription factors , leucine , heptad repeat , mutagenesis , transcription factor , site directed mutagenesis , mutation , binding site , biology , transcription (linguistics) , dna binding protein , microbiology and biotechnology , chemistry , biochemistry , gene , amino acid , peptide sequence , mutant , linguistics , philosophy
Abstract Jun and fos oncoproteins form a complex which regulates transcription from promoters containing AP‐I binding sites. The “leucine zipper” domain of both fos and jun is necessary for the formation of the heterodimer, but the role of specific leucine residues is unclear. We have used site‐specific mutagenesis to examine the contribution of individual leucine residues to the formation of a stable fos/jun protein complex and the binding of this complex to the AP‐1 site. Mutation of a single leucine in either fos or jun had no effect on protein complex formation. Furthermore, mutations of two consecutive leucines in jun did not interfere with heterodimer formation; however, in the case of fos, two consecutive mutations resulted in an inability to form a heterodimer. Although mutagenesis of the first leucine of the heptad repeat had no effect on protein complex formation, this mutation in either fos or jun drastically reduced the affinity of the complex for DNA. Thus, both fos and jun contribute directly to the DNA binding potential of the heterodimer.