MicroRNA-122: A New Player in the Negative Regulation of LH Receptor Expression by the LH Receptor mRNA Binding Protein (LRBP)

Treatment of human pleural mesothelioma (MS-1) cells with phorbol myristate acetate (PMA) and cycloheximide results in 17- and 10-fold, respectively, increases in steady-state expression of urokinase-type plasminogen activator receptor (uPAR) mRNA. Studies of transcriptional inhibition by actinomycin D showed four- and sixfold extensions of uPAR mRNA half-life in MS-1 cells treated with PMA and cycloheximide, respectively, suggesting that uPAR gene expression involves a posttranscriptional regulatory mechanism. Using gel mobility shift and UV cross-linking assays, we identified a 50-kDa uPAR mRNA binding protein (uPAR mRNABp) that selectively bound to a 51-nucleotide (nt) fragment of mRNA corresponding to the uPAR coding region. We investigated the possibility that this 51-nt protein binding fragment of uPAR mRNA contains regulatory information for message stability. Chimeric beta-globin/uPAR/beta-globin mRNA containing the 51-nt protein binding fragment was able to destabilize otherwise stable beta-globin mRNA. Conversely, a control chimeric beta-globin/uPAR/beta-globin mRNA containing a 51-nt fragment of the uPAR coding region that does not bind uPAR mRNABp was stable under identical conditions. Binding of uPAR mRNABp to uPAR mRNA was abolished after treatment with cycloheximide and rapidly down-regulated by PMA. These data suggest that the 51-nt protein binding fragment of uPAR mRNA may be involved in mRNA turnover as well as in cycloheximide-induced uPAR message stabilization. Our results indicate a novel mechanism of uPAR gene regulation in which cis elements within a 51-nt coding region interact with a uPAR mRNABp to regulate uPAR message stability.

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TheMr35,000 β-Adrenergic Receptor mRNA-binding Protein Binds Transcripts of G-protein-linked Receptors Which Undergo Agonist-induced Destabilization

Journal of Biological Chemistry ◽

10.1074/jbc.270.21.12787 ◽

1995 ◽

Vol 270 (21) ◽

pp. 12787-12793 ◽

Cited By ~ 44

Author(s):

Baby G. Tholanikunnel ◽

James G. Granneman ◽

Craig C. Malbon

Keyword(s):

G Protein ◽

Adrenergic Receptor ◽

Binding Protein ◽

Receptor Mrna ◽

Mrna Binding Protein ◽

Mrna Binding

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Evidence for the association of luteinizing hormone receptor mRNA-binding protein with the translating ribosomes during receptor downregulation

Biochimica et Biophysica Acta (BBA) - Molecular Cell Research ◽

10.1016/j.bbamcr.2009.08.009 ◽

2009 ◽

Vol 1793 (11) ◽

pp. 1787-1794 ◽

Cited By ~ 16

Author(s):

Bindu Menon ◽

Helle Peegel ◽

K.M.J. Menon

Keyword(s):

Luteinizing Hormone ◽

Hormone Receptor ◽

Binding Protein ◽

Luteinizing Hormone Receptor ◽

Receptor Downregulation ◽

Receptor Mrna ◽

Mrna Binding Protein ◽

Mrna Binding

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Post-Transcriptional Control of Renal Mineralocorticoid Receptor Expression by the mRNA Binding Protein Tis11b and MicroRNAs under Hypertonic Stress.

10.1210/endo-meetings.2010.part3.p13.p3-613 ◽

2010 ◽

pp. P3-613-P3-613

Author(s):

S Viengchareun ◽

V Keo ◽

G Meduri ◽

F Brioude ◽

J Bouligand ◽

...

Keyword(s):

Mineralocorticoid Receptor ◽

Transcriptional Control ◽

Binding Protein ◽

Receptor Expression ◽

Hypertonic Stress ◽

Mrna Binding Protein ◽

Mrna Binding

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Regulation of LH Receptor mRNA Binding Protein by miR-122 in Rat Ovaries

Endocrinology ◽

10.1210/en.2013-1619 ◽

2013 ◽

Vol 154 (12) ◽

pp. 4826-4834 ◽

Cited By ~ 29

Author(s):

Bindu Menon ◽

Jennifer Sinden ◽

Meghan Franzo-Romain ◽

Raman Bhadradri Botta ◽

K. M. J. Menon

Keyword(s):

Nucleic Acid ◽

Mrna Expression ◽

Signaling Pathways ◽

Binding Protein ◽

Locked Nucleic Acid ◽

Down Regulation ◽

Lh Receptor ◽

Mrna Binding Protein ◽

Mrna Binding

LH receptor (LHR) expression in the ovary is regulated by the RNA binding protein, (LHR mRNA binding protein [LRBP]), which has been identified as being mevalonate kinase. This study examined the role of microRNA miR-122 in LRBP-mediated LHR mRNA expression. Real-time PCR analysis of ovaries from pregnant mare serum gonadotropin/human chorionic gonadotropin (hCG)-primed female rats treated with hCG to down-regulate LHR expression showed that an increase in miR-122 expression preceded LHR mRNA down-regulation. The expression of miR-122 and its regulation was confirmed using fluorescent in situ hybridization of the frozen ovary sections using 5′-fluorescein isothiocyanate-labeled miR-122 locked nucleic acid probe. The increased expression of miR-122 preceded increased expression of LRBP mRNA and protein, and these increases were followed by LHR mRNA down-regulation. Inhibition of protein kinase A (PKA) and ERK1/2 signaling pathways by H89 and UO126, respectively, attenuated the hCG-mediated up-regulation of miR-122 levels. This was also confirmed in vitro using human granulosa cells. These results suggest the possibility that hCG-mediated miR-122 expression is mediated by the activation of cAMP/PKA/ERK signaling pathways. Inhibition of miR-122 by injection of the locked nucleic acid-conjugated antagomir of miR-122 abrogated the hCG-mediated increases in LRBP protein expression. Because it has been previously shown that miR-122 regulates sterol regulatory element-binding proteins (SREBPs) and SREBPs, in turn, regulate LRBP expression, the role of SREBPs in miR-122-mediated increase in LRBP expression was then examined. The levels of active forms of both SREBP-1a and SREBP-2 were increased in response to hCG treatment, and the stimulatory effect was sustained up to 4 hours. Taken together, our results suggest that hCG-induced down-regulation of LHR mRNA expression is mediated by activation of cAMP/PKA/ERK pathways to increase miR-122 expression, which then increases LRBP expression through the activation of SREBPs.

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Luteinizing Hormone Receptor mRNA Down-Regulation Is Mediated through ERK-Dependent Induction of RNA Binding Protein

Molecular Endocrinology ◽

10.1210/me.2010-0366 ◽

2011 ◽

Vol 25 (2) ◽

pp. 282-290 ◽

Cited By ~ 27

Author(s):

Bindu Menon ◽

Megan Franzo-Romain ◽

Shadi Damanpour ◽

K. M. J. Menon

Keyword(s):

Granulosa Cells ◽

Rna Binding ◽

Binding Protein ◽

Primary Cultures ◽

Binding Activity ◽

Luteinizing Hormone Receptor ◽

Down Regulation ◽

Lh Receptor ◽

Receptor Mrna ◽

Mrna Binding

Abstract The ligand-induced down-regulation of LH receptor (LHR) expression in the ovaries, at least in part, is regulated by a posttranscriptional process mediated by a specific LH receptor mRNA binding protein (LRBP). The LH-mediated signaling pathways involved in this process were examined in primary cultures of human granulosa cells. Treatment with 10 IU human chorionic gonadotropin (hCG) for 12 h resulted in the down-regulation of LHR mRNA expression while producing an increase in LHR mRNA binding to LRBP as well as a 2-fold increase in LRBP levels. The activation of ERK1/2 pathway in LH-mediated LHR mRNA down-regulation was also established by demonstrating the translocation of ERK1/2 from the cytosol to the nucleus using confocal microcopy. Inhibition of protein kinase A using H-89 or ERK1/2 by U0126 abolished the LH-induced LHR mRNA down-regulation. These treatments also abrogated both the increases in LRBP levels as well as the LHR mRNA binding activity. The abolishment of the hCG-induced increase in LRBP levels and LHR mRNA binding activity was further confirmed by transfecting granulosa cells with ERK1/2 specific small interfering RNA. This treatment also reversed the hCG-induced down-regulation of LHR mRNA. These data show that LH-regulated ERK1/2 signaling is required for the LRBP-mediated down-regulation of LHR mRNA.

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