Transforming growth factor-beta1 stimulates multiple protein interactions at a unique cis-element in the 3'-untranslated region of the hyaluronan receptor RHAMM mRNA.
The receptor for hyaluronan mediated motility (RHAMM) gene expression is markedly elevated in fibrosarcomas exposed to transforming growth factor-beta1 (TGF-beta1). The half-life of RHAMM mRNA was increased by 3 fold in cells treated with TGF-beta1, indicating that growth factor regulation of RHAMM gene expression at least in part involves a posttranscriptional mechanism. Our studies demonstrated that a unique 30-nucleotide (nt) region that has three copies of the sequence, GCUUGC, was the TGF-beta1-responsive region in the 3'-untranslated region (3'-UTR) that mediated message stability. This region interacted specifically with cytoplasmic trans-factors to form multiple protein complexes of approximately 175, 97, 63, 26, and 17 kDa post-TGF-beta1 treatment, suggesting a role for these complexes in the mechanism of action of TGF-beta1-induced message stabilization. Insertion of the 3'-UTR into the chloramphenicol acetyltransferase gene conferred TGF-beta1 induced stability of chloramphenicol acetyltransferase-hybrid RNA in stably transfected cells, while the same insert carrying a deletion containing the 30-nt region had no significant effect on mRNA stability. These results provide a model of RHAMM message regulation in which TGF-beta1-mediated alteration of RHAMM message stability involves the up-regulation of multiple protein interactions with a 30-nt cis-element stability determinant in the 3'-UTR. This model also suggests that this 30-nt base region functions in cis to destabilize RHAMM mRNA in resting normal cells.
Amara
F M
FM
Manitoba Institute of Cell Biology, University of Manitoba, Winnipeg, Manitoba R3E 0V9, Canada.
Entwistle
J
J
Kuschak
T I
TI
Turley
E A
EA
Wright
J A
JA
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D015500:Chloramphenicol O-Acetyltransferase / Q000096:biosynthesis; D016326:Extracellular Matrix Proteins / Q000096:biosynthesis*; D005354:Fibrosarcoma; D005786:Gene Expression Regulation / Q000187:drug effects*; D018960:Hyaluronan Receptors / Q000096:biosynthesis*; D051379:Mice; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes; D009843:Oligoribonucleotides; D014176:Protein Biosynthesis / Q000187:drug effects; D012333:RNA, Messenger / Q000737:chemistry / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis; D014158:Transcription, Genetic; D014162:Transfection; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
D016326:Extracellular Matrix Proteins; D018960:Hyaluronan Receptors; D015345:Oligonucleotide Probes; D009843:Oligoribonucleotides; D012333:RNA, Messenger; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C098946:hyaluronan-mediated motility receptor; D015500:Chloramphenicol O-Acetyltransferase