Differential regulation of the rat heme oxygenase-1 expression by Ets oncoproteins in glomerular mesangial cells.
The Ets-1 oncoprotein and the heme-catabolizing enzyme heme oxygenase (HO)-1 have been implicated in the pathogenesis of renal disease. We investigated the role of the putative Ets-binding sites (EBSs) in the transactivation of the proximal promoter of rat heme oxygenase 1 (hmox1) gene by the Ets oncoproteins Fli-1, Erg-2, and Ets-1 in mesangial cells. We examined several rat hmox1-chloramphenicol acetytransferase (CAT) constructs and EBS mutant constructs in an effort to assess the effect of ETS oncoproteins on transactivation of the rat hmox1 proximal promoter in renal glomerular mesangial cells. CAT assays demonstrated that the proximal promoter region (-1387 to -40) contains positive and negative regulatory regions and that the EBS-2, 3, and 4 play a role in basal promoter activity. Overexpression of Fli-1 and Erg-2 proteins showed a significant increase in promoter activity, whereas Ets-1 showed no effect on promoter activity. The Fli-1-induced transcriptional activation was not altered by mutation of EBSs, either independently or in combination. However, mutation of EBS-4 independently or a combined mutation of sites 3 and 4 led to a 50% reduction in Erg-2-induced transcriptional activation. Furthermore, mutation of EBS-2 and 4 completely abolished Erg-2-mediated promoter activation. Our results support a role for Ets transcription factors in the regulation of rat hmox-1 gene expression in mesangial cells.
Dhulipala
Prasad D K
PD
Department of Medicine, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, New Brunswick, NJ 08903-0019, USA.
Datta
Prasun K
PK
Reddy
E Shyam
ES
Lianos
Elias A
EA
D000818:Animals; D002478:Cells, Cultured; D051638:Ether-A-Go-Go Potassium Channels / Q000235:genetics / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D005920:Glomerular Mesangium / Q000166:cytology / Q000201:enzymology*; D006419:Heme Oxygenase (Decyclizing) / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D017354:Point Mutation; D050784:Proto-Oncogene Protein c-ets-1 / Q000235:genetics* / Q000378:metabolism; D051789:Proto-Oncogene Protein c-fli-1 / Q000235:genetics / Q000378:metabolism; D051381:Rats; D015533:Transcriptional Activation
D051638:Ether-A-Go-Go Potassium Channels; C109500:Kcnh6 protein, rat; D050784:Proto-Oncogene Protein c-ets-1; D051789:Proto-Oncogene Protein c-fli-1; D006419:Heme Oxygenase (Decyclizing); C491523:Hmox1 protein, rat