Id proteins not only regulate cell differentiation negatively, but they also promote growth, immortalization, and apoptosis. To know the mechanism of how Id regulates cell fate, we previously isolated an Id-associating protein, MIDA1, which positively regulates cell growth. Its predicted amino acid sequence consists of a Zuotin (a Z-DNA binding protein in yeast) homology region and tryptophan-mediated repeats (Tryp-med repeats). MIDA1 exhibits a sequence-specific DNA binding activity through the Tryp-med repeats. In this study, we revealed that, like Zuotin, MIDA1 can specifically bind to Z-DNA. This suggested that MIDA is a novel DNA binding protein that has two different DNA binding activities. Furthermore, association of Id1 with MIDA1 stimulated the sequence-specific DNA binding activity, while it inhibited the Z-DNA binding activity. Therefore, we concluded that MIDA1 may act as a mediator of the growth-promoting function of Id, by switching the two DNA binding activities of MIDA1.
|Number of pages||5|
|Journal||Biochemical and biophysical research communications|
|Publication status||Published - 1999 Dec 9|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology