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Autoregulation of co‐chaperone BAG3 gene transcription
Author(s) -
Gentilella Antonio,
Khalili Kamel
Publication year - 2009
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.22343
Subject(s) - bag3 , microbiology and biotechnology , biology , heat shock protein , transcription factor , cytoplasm , gene , transcription (linguistics) , hek 293 cells , chaperone (clinical) , gene product , gene expression , autophagy , genetics , medicine , apoptosis , linguistics , philosophy , pathology
The Bcl‐2‐associated athanogene, BAG, protein family through their BAG domain associates with the heat shock protein 70 (HSP‐70) and modulates its chaperone activity. One member of this family, BAG3, appears to play an important role in protein homeostasis, as its expression promotes cell survival. Expression of BAG3 is enhanced by a variety of stress‐inducing agents. Here we describe a role for BAG3 to modulate transcription of its own promoter through a positive feedback loop involving its 5′‐UTR sequence. Activation of the BAG3 promoter is mediated by the BAG domain and is independent of BAG3 association with the UTR sequence. Autoactivation of the BAG3 gene is observed in several cultures of human glial cells including gliomas, but not in several other non‐glial cell lines such as He La and others. Results from cell fractionation and immunocytochemistry showed BAG3 in the cytoplasm as well as the nuclei of glial cells. These observations suggest that BAG3 gene expression is controlled by its own product and that this may be critical for the biological activity of BAG3 in some cell types. J. Cell. Biochem. 108: 1117–1124, 2009. © 2009 Wiley‐Liss, Inc.