title: c-Abl regulates early growth response protein (EGR1) in response to oxidative stress.
abstract: c-Abl is a tyrosine kinase that can act as a regulator of cell growth and apoptosis in response to stress. Using cell lines expressing c-Abl in an inducible manner, we identified genes whose expression was regulated by c-Abl kinase activity. Microarray analysis indicated that Early Growth Response-1 (EGR1) gene expression is induced by c-Abl kinase activity, which was confirmed at the message and protein levels. Promoter mapping experiments revealed that c-Abl utilizes three distal serum response elements (SREs) in the EGR1 promoter, which are transactivated by mitogen/extracellular receptor kinase (MEK/ERK) signaling. PD 95089, a specific inhibitor of MEK/ERK signaling, attenuated c-Abl-mediated upregulation of EGR1 expression in a dose-dependent manner. Similar results were obtained by using a dominant-negative mutant of mitogen/extracellular kinase. Significantly, hydrogen peroxide-induced EGR1 expression appears to be mediated by c-Abl, as cells expressing dominant negative c-Abl, and c-Abl-/- murine embryonic fibroblasts, are completely defective in hydrogen peroxide-induced EGR1 expression. In addition, c-Abl-induced apoptosis is partially mitigated by EGR1 activity, as cells devoid of EGR1 expression undergo reduced rates of c-Abl-induced apoptosis. Together, these results indicate that c-Abl promotes the induction of EGR1 through the MEK/ERK pathway in regulating apoptotic response to oxidative stress.
authors.affiliation: Department of Genetics and Complex Diseases, Harvard School of Public Health, Boston, MA 02115, USA.
authors.forename: Jeremy R
authors.initials: JR
authors.lastname: Stuart
authors.forename: Hidehiko
authors.initials: H
authors.lastname: Kawai
authors.forename: Kelvin K C
authors.initials: KK
authors.lastname: Tsai
authors.forename: Eric Y
authors.initials: EY
authors.lastname: Chuang
authors.forename: Zhi-Min
authors.initials: ZM
authors.lastname: Yuan
mesh_terms: D000818:Animals; D017209:Apoptosis; D002460:Cell Line; D051766:Early Growth Response Protein 1 / Q000235:genetics* / Q000378:metabolism; D005347:Fibroblasts / Q000502:physiology; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D020935:MAP Kinase Signaling System; D051379:Mice; D020411:Oligonucleotide Array Sequence Analysis; D018384:Oxidative Stress; D011401:Promoter Regions, Genetic; D016315:Proto-Oncogene Proteins c-abl / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection
chemical_list: C497325:EGR1 protein, human; D051766:Early Growth Response Protein 1; C486109:Egr1 protein, mouse; D006861:Hydrogen Peroxide; D016315:Proto-Oncogene Proteins c-abl