Novel binding of HuR and poly(C)-binding protein to a conserved UC-rich motif within the 3'-untranslated region of the androgen receptor messenger RNA.
The androgen receptor (AR) mediates androgen action and plays a central role in the proliferation of specific cancer cells. We demonstrated recently that AR mRNA stability is a major determinant of AR gene expression in prostate and breast cancer cells and that androgens differentially regulate AR mRNA decay dependent on cell type (Yeap, B. B., Kreuger, R. G., Leedman, P. J. (1999) Endocrinology 140, 3282-3291). Here, we have identified a highly conserved UC-rich region in the 3-untranslated region of AR mRNA that contains a 5'-C(U)(n)C motif and a 3'-CCCUCCC poly(C)-binding protein motif. In transfection studies with LNCaP human prostate cancer cells, the AR UC-rich region reduced expression of a luciferase reporter gene. The AR UC-rich region was a target for cytoplasmic and nuclear RNA-binding proteins from human prostate and breast cancer cells as well as human testicular and breast cancer tissue. One of these proteins is HuR, a ubiquitously expressed member of the Elav/Hu family of RNA-binding proteins involved in the stabilization of several mRNAs. Poly(C)-binding protein-1 and -2 (CP1 and CP2), previously implicated in the control of mRNA turnover and translation, also bound avidly to the UC-rich region. Mutational analysis of the UC-rich region identified specific binding motifs for both HuR and the CPs. HuR and CP1 bound simultaneously to the UC-rich RNA and in a cooperative manner. Immunoprecipitation studies confirmed that each of these proteins associated with AR mRNA in prostate cancer cells. In summary, we have identified and characterized a novel complex of AR mRNA-binding proteins that target the highly conserved UC-rich region. The binding of HuR, CP1, and CP2 to AR mRNA suggests a role for each of these proteins in the post-transcriptional regulation of AR expression in cancer cells.
Yeap
Bu B
BB
Laboratory for Cancer Medicine, Western Australian Institute for Medical Research, University Department of Medicine, University of Western Australia, 50 Murray Street, Perth, WA 6000, Australia.
Voon
Dominic C
DC
Vivian
Julian P
JP
McCulloch
Ross K
RK
Thomson
Andrew M
AM
Giles
Keith M
KM
Czyzyk-Krzeska
Maria F
MF
Furneaux
Henry
H
Wilce
Matthew C J
MC
Wilce
Jackie A
JA
Leedman
Peter J
PJ
D020413:3' Untranslated Regions; D020816:Amino Acid Motifs; D000818:Animals; D000954:Antigens, Surface; D002455:Cell Division; D002467:Cell Nucleus / Q000378:metabolism; D003432:Cross-Linking Reagents / Q000494:pharmacology; D003593:Cytoplasm / Q000378:metabolism; D004268:DNA-Binding Proteins; D004305:Dose-Response Relationship, Drug; D051959:ELAV Proteins; D000067780:ELAV-Like Protein 1; D005982:Glutathione Transferase / Q000378:metabolism; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D006801:Humans; D008156:Luciferases / Q000378:metabolism; D051379:Mice; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D012333:RNA, Messenger / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism*; D051381:Rats; D011944:Receptors, Androgen / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors; D014162:Transfection; D014407:Tumor Cells, Cultured
D020413:3' Untranslated Regions; D000954:Antigens, Surface; D003432:Cross-Linking Reagents; D004268:DNA-Binding Proteins; D051959:ELAV Proteins; D000067780:ELAV-Like Protein 1; C098770:ELAVL1 protein, human; D034441:Heterogeneous-Nuclear Ribonucleoproteins; C094604:PCBP1 protein, human; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D011944:Receptors, Androgen; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D008156:Luciferases; D005982:Glutathione Transferase