TY - JOUR
T1 - Urea-inducible Egr-1 transcription in renal inner medullary collecting duct (mIMCD3) cells is mediated by extracellular signal-regulated kinase activation
AU - Cohen, David M.
PY - 1996/10/1
Y1 - 1996/10/1
N2 - Urea (200-400 milliosmolar) activates transcription, translation of, and trans-activation by the immediate-early gene transcription factor Egr-1 in a renal epithelial cell-specific fashion. The effect at the transcriptional level has been attributed to multiple serum response elements and their adjacent Ets motifs located within the Egr-1 promoter. Elk-1, a principal ternary complex factor and Ets domain-containing protein, is a substrate of the extracellular signal-regulated kinase (ERK) mitogen-activated protein kinases. In the renal medullary mIMCD3 cell line, urea (200-400 milliosmolar) activated both ERK1 and ERK2 as determined by in-gel kinase assay and immune- complex kinase assay of epitopetagged ERK1 and ERK2. Importantly, urea did not affect abundance of either ERK. Urea-inducible Egr-1 transcription was a consequence of ERK activation because the ERKspecific inhibitor, PD98059, abrogated transcription from the murine Egr-1 promoter in a luciferase reporter gene assay. In addition, activators of protein kinase A, including forskolin and g-Br-cAMP, which are known to inhibit ERK-mediated events, also inhibited urea-inducible Egr-1 transcription. Furthermore, urea-inducible activation of the physiological ERK substrate and transcription factor, Elk- 1, was demonstrated through transient cotransfection of a chimeric Elk- 1/GAL4 expression plasmid and a GAL4-driven luciferase reporter plasmid. Taken together, these data indicate that, in mIMCD3 cells, urea activates ERKs and the ERK substrate, Elk-l, and that ERK inhibition abrogates urea- inducible Egr-1 transcription. These data are consistent with a model of ureainducible renal medullary gene expression wherein sequential activation of ERKs and Elk-1 results in increased transcription of ERr-1 through serum response element/Ets motifs.
AB - Urea (200-400 milliosmolar) activates transcription, translation of, and trans-activation by the immediate-early gene transcription factor Egr-1 in a renal epithelial cell-specific fashion. The effect at the transcriptional level has been attributed to multiple serum response elements and their adjacent Ets motifs located within the Egr-1 promoter. Elk-1, a principal ternary complex factor and Ets domain-containing protein, is a substrate of the extracellular signal-regulated kinase (ERK) mitogen-activated protein kinases. In the renal medullary mIMCD3 cell line, urea (200-400 milliosmolar) activated both ERK1 and ERK2 as determined by in-gel kinase assay and immune- complex kinase assay of epitopetagged ERK1 and ERK2. Importantly, urea did not affect abundance of either ERK. Urea-inducible Egr-1 transcription was a consequence of ERK activation because the ERKspecific inhibitor, PD98059, abrogated transcription from the murine Egr-1 promoter in a luciferase reporter gene assay. In addition, activators of protein kinase A, including forskolin and g-Br-cAMP, which are known to inhibit ERK-mediated events, also inhibited urea-inducible Egr-1 transcription. Furthermore, urea-inducible activation of the physiological ERK substrate and transcription factor, Elk- 1, was demonstrated through transient cotransfection of a chimeric Elk- 1/GAL4 expression plasmid and a GAL4-driven luciferase reporter plasmid. Taken together, these data indicate that, in mIMCD3 cells, urea activates ERKs and the ERK substrate, Elk-l, and that ERK inhibition abrogates urea- inducible Egr-1 transcription. These data are consistent with a model of ureainducible renal medullary gene expression wherein sequential activation of ERKs and Elk-1 results in increased transcription of ERr-1 through serum response element/Ets motifs.
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U2 - 10.1073/pnas.93.20.11242
DO - 10.1073/pnas.93.20.11242
M3 - Article
C2 - 8855340
AN - SCOPUS:0029773878
SN - 0027-8424
VL - 93
SP - 11242
EP - 11247
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 20
ER -