Heterodimerization among the basic-leucine zipper (bZIP) proteins or among the basic-helix – loop – helix-leucine zipper (bHLHZip) proteins confers a multitude of combinational activities to these transcription factors. To further examine the function of the bHLHZip protein, USF, we screened for cellular proteins which could directly interact with USF using the yeast two-hybrid system. A bZip protein, Fra1, was found to efficiently interact with USF. USF specifically interacts with Fra1 but not with other closely related family members, c-Fos, Fra2, FosB, or with c-Jun. Both the bHLHZip and the N-terminal regions of Fra1 are required for efficient interaction with USF.In vivo association between USF and Fra1 has been demonstrated by co-immunoprecipitation. Expression of exogenous USF led to a decrease in AP1-dependent transcription in F9 cells. Co-expression of exogenous Fra1 restored the AP1 activity in a dose-dependent manner. These data show that USF and Fra1 physically and functionally interact demonstrating that cross-talk occurs between factors of distantly related transcription families.

• Exploration of nucleosome positioning patterns in transcription factor function

  • Kazumitsu Maehara
  • Yasuyuki Ohkawa

  Scientific Reports (2016)

• Cross-regulatory interaction between Stra13 and USF results in functional antagonism

  • Manya Dhar
  • Reshma Taneja

  Oncogene (2001)

• Close encounters of many kinds: Fos-Jun interactions that mediate transcription regulatory specificity

  • Yurii Chinenov
  • Tom K Kerppola

  Oncogene (2001)

• Conversion of HPV 18 positive non-tumorigenic HeLa-fibroblast hybrids to invasive growth involves loss of TNF-α mediated repression of viral transcription and modification of the AP-1 transcription complex

  • Ubaldo Soto
  • Bhudev Chandra Das
  • Frank Rösl

  Oncogene (1999)