Nucleic Acids Research, 2003, Vol. 31, No. 8 2209-2216
© 2003 Oxford University Press
Transcriptional stimulation by the DNA binding protein Hap46/BAG-1M involves hsp70/hsc70 molecular chaperones
Molekulare Evolution und Genomik, Im Neuenheimer Feld 230, and Biochemie-Zentrum Heidelberg, D-69120 Heidelberg, Germany
*To whom correspondence should be addressed. Tel: +49 6221 545256; Fax: +49 6221 545678; Email: ugehring{at}sun0.urz.uni-heidelberg.de
The hsp70/hsc70-associating protein Hap46 of human origin, also called BAG-1M (Bcl-2-associated athanogene 1), has been characterized previously as a DNA binding protein, which is able to stimulate transcription. By use of in vitro assays we now show that Hap46-mediated transcriptional activation can occur from linearized as well as from supercoiled circular DNA and does not require the presence of a transcription promoter. Accordingly, we observed no preferential binding of Hap46 to overlapping DNA fragments covering the sequence of the cytomegalovirus (CMV) early promoter, thus suggesting non-specific binding. The C-terminal deletion variant Hap46
C47, which is unable to associate with hsp70/hsc70 molecular chaperones, produced greatly diminished effects on transcription, indicating a significant involvement of hsp70/hsc70 chaperones but not an absolute requirement. In contrast, deletion of the acidic hexarepeat region, as in variant Hap46
12-62, did not disturb transcriptional stimulation. While full-length Hap46 readily formed complexes with a series of structurally unrelated transcription factors, variant Hap46
C47 proved incapable of doing so. Together these data suggest that transcriptional stimulation is a major biological activity of Hap46 and point to involvement of hsp70/hsc70 molecular chaperones in transcription in concert with Hap46, thus providing a link between hsp70/hsc70 molecular chaperones and components of the transcription machinery.
![]()
CiteULike
Connotea
Del.icio.us What's this?
This article has been cited by other articles:
![]() |
K. P. Kauppinen, F. Duan, J. I. Wels, and D. Manor Regulation of the Dbl Proto-oncogene by Heat Shock Cognate Protein 70 (Hsc70) J. Biol. Chem., June 3, 2005; 280(22): 21638 - 21644. [Abstract] [Full Text] [PDF] |
||||
