Transcriptional control of human antigen R by bone morphogenetic protein.
Human antigen R (HuR) is an RNA-binding protein with protective activities against cellular stress. This study considers the mechanisms by which HuR transcriptional regulation occurs in renal proximal tubule cells. Under basal conditions, HuR mRNA is expressed in two forms: one that contains a approximately 20-base 5'-untranslated region (UTR) sequence and one that contains a approximately 150-base, G+C-rich 5'-UTR that is inhibitory to translation. Recovery from cellular stresses such as thapsigargin and ATP depletion induced increased expression of the shorter, more translatable transcript and decreased expression of the longer form. Analysis of HuR upstream regions revealed sequences necessary for regulation of the shorter mRNA. Within the long, G+C-rich 5'-UTR exist multiple copies of the alternate Smad 1/5/8-binding motif GCCGnCGC. Recovery from ATP depletion induced increases in Smad 1/5/8 levels; further, gel shift and chromatin immunoprecipitation analyses demonstrated the ability of these Smads to bind to the relevant motif in the HuR 5'-UTR. Transfection of exogenous Smad 1 increased HuR mRNA expression. Finally, HuR mRNA expression driven by the Smad-binding sites was responsive to BMP-7, a protein with known protective effects against ischemic injury in kidney. These data suggest that transcriptional induction of a readily translatable HuR mRNA may be driven by a mechanism known to protect the kidney from injury and provides a novel pathway through which administration of BMP-7 may attenuate renal damage.
Jeyaraj
Selvi C
SC
Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Columbus, Ohio 43210, USA.
Singh
Mamata
M
Ayupova
Dina A
DA
Govindaraju
Suman
S
Lee
Beth S
BS
D020121:5' Untranslated Regions / Q000235:genetics; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D000954:Antigens, Surface / Q000235:genetics*; D001482:Base Composition / Q000235:genetics; D015153:Blotting, Western; D055419:Bone Morphogenetic Protein 7 / Q000494:pharmacology*; D002460:Cell Line; D047369:Chromatin Immunoprecipitation; D051959:ELAV Proteins; D000067780:ELAV-Like Protein 1; D024202:Electrophoretic Mobility Shift Assay; D004797:Enzyme-Linked Immunosorbent Assay; D007150:Immunohistochemistry; D011401:Promoter Regions, Genetic / Q000187:drug effects / Q000235:genetics; D011485:Protein Binding / Q000235:genetics / Q000502:physiology; D016601:RNA-Binding Proteins / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051898:Smad1 Protein / Q000235:genetics / Q000378:metabolism; D051902:Smad5 Protein / Q000235:genetics / Q000378:metabolism; D051904:Smad8 Protein / Q000235:genetics / Q000378:metabolism; D013552:Swine; D014158:Transcription, Genetic / Q000187:drug effects* / Q000235:genetics
D020121:5' Untranslated Regions; D000954:Antigens, Surface; D055419:Bone Morphogenetic Protein 7; D051959:ELAV Proteins; D000067780:ELAV-Like Protein 1; C098770:ELAVL1 protein, human; D016601:RNA-Binding Proteins; D051898:Smad1 Protein; D051902:Smad5 Protein; D051904:Smad8 Protein; D000255:Adenosine Triphosphate