Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Nuclear Export Signals”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,405 records · Page 78Linked to original sources
PubMed2005

CSN5/Jab1 is involved in ligand-dependent degradation of estrogen receptor {alpha} by the proteasome.

Here, we show that estrogen receptor alpha (ERalpha) coimmunoprecipitates with CSN5/Jab1, a subunit of the COP9 signalosome (CSN), and that overexpression of CSN5/Jab1 causes an increase in ligand-induced ERalpha degradation. Inhibition of either the kinase activity associated with the CSN complex by curcumin or of nuclear export by leptomycin B (LMB) impaired estradiol-induced ERalpha degradation by the proteasome. Degradation of ERalpha induced by the pure antagonist ICI 182,780 (ICI) was blocked by curcumin but not by LMB, indicating that in the presence of ICI, ERalpha is degraded by a nuclear fraction of the proteasome. In addition, we observed that curcumin inhibited estradiol-induced phosphorylation of ERalpha. The use of three inhibitors of ERalpha degradation that target different steps of the estrogen response pathway (inhibition of the CSN-associated kinase, nuclear export, and proteasome) suggests that a phosphorylation event inhibited by curcumin is necessary for ERalpha binding to its cognate DNA target. Our results demonstrate that transcription per se is not required for ERalpha degradation and that assembly of the transcription-initiation complex is sufficient to target ERalpha for degradation by the proteasome.

Active Transport, Cell Nucleus↗
PubMed1995

Fungal lipopeptide mating pheromones: a model system for the study of protein prenylation.

In a variety of fungal species, mating between haploid cells is initiated by the action of peptide pheromones. The identification and characterization of several fungal pheromones has revealed that they have common structural features classifying them as lipopeptides. In the course of biosynthesis, these pheromones undergo a series of posttranslational processing events prior to export. One common modification is the attachment of an isoprenoid group to the C terminus of the pheromone precursor. Genetic and biochemical investigations of this biosynthetic pathway have led to the elucidation of genes and enzymes which are responsible for isoprenylation of other polypeptides including the nuclear lamins, several vesicular transport proteins, and the oncogene product Ras. The alpha-factor of Saccharomyces cerevisiae serves as a model for studying the biosynthesis, export, and bioactivity of lipopeptide pheromones. In addition to being isoprenylated with a farnesyl group, the alpha-factor is secreted by a novel peptide export pathway utilizing a yeast homolog of the mammalian multidrug resistance P-glycoprotein. The identification of putative lipopeptide-encoding loci within other fungi, including the human immunodeficiency virus-associated opportunistic pathogen Cryptococcus neoformans and the plant pathogen Ustilago maydis, has stimulated much interest in understanding possible roles for pheromones in fungal proliferation and pathogenicity. Knowledge of variations within the processing, export, and receptor-mediated signal transduction pathways associated with different fungal lipopeptide pheromones will continue to provide insights into similar mechanisms which exist in higher eukaryotes.

Amino Acid Sequence↗
PubMed1996

Determinants of subcellular distribution of the glucocorticoid receptor.

Glucocorticoid receptor (GR) exchanges between an active nuclear form and a complexed inactive, steroid-sensitive cytoplasmic form. Using a semi-quantitative indirect immunofluorescence assay to measure the kinetics of subcellular redistribution of GR in response to challenge during G(o), we have found that the ability to bind DNA is an important determinant for localization and tight binding of GR to the nucleus. The transfer of GR DNA-binding mutants to the nucleus after treatment with hormone agonists and antagonists was markedly reduced. Further, mutant receptors localized to the nucleus were only weakly associated with the nuclear compartment as they were released into cytosol upon hypotonic lysis of the cell membrane. Moreover, after agonist withdrawal, GR redistributed to the cytoplasm more rapidly when unable to bind DNA. By contrast, withdrawal of the hormone antagonist RU486 was found to yield a form of wild type GR that was completely unable to redistribute to the cytoplasm. However, this did not appear to result from a block in nuclear export as selective inactivation of nuclear import with energy inhibitor released RU486-withdrawn GRs from the nucleus at the same rates as agonist-withdrawn receptors. In addition, GR mutants unable to bind DNA, which retained a significant presence in the cytoplasm both during and after antagonist treatment, also failed to redistribute. The effect of RU486 treatment did not appear to be mediated through a block in reassociation of GR into a steroid-responsive form as RU486-withdrawn wild type receptors retained full potential to activate transcription from a glucocorticoid-responsive promoter after a second challenge with hormone. Therefore, reassociation of GR into a steroid-responsive form appears to be independent of signals important for the retention of GR in the cytoplasm.

Animals↗
PubMed1999

Saccharomyces cerevisiae Mod5p-II contains sequences antagonistic for nuclear and cytosolic locations.

MOD5 encodes a tRNA modification activity located in three subcellular compartments. Alternative translation initiation generates Mod5p-I, located in the mitochondria and the cytosol, and Mod5p-II, located in the cytosol and nucleus. Here we study the nucleus/cytosol distribution of overexpressed Mod5p-II. Nuclear Mod5p-II appears concentrated in the nucleolus, perhaps indicating that the nuclear pool may have a different biological role than the cytoplasmic and mitochondrial pools. Mod5p contains three motifs resembling bipartite-like nuclear localization sequences (NLSs), but only one is sufficient to locate a passenger protein to the nucleus. Mutations of basic residues of this motif cumulatively contribute to a cytosolic location for the fusion proteins. These alterations also cause decreased nuclear pools of endogenous Mod5p-II. Depletion of nuclear Mod5p-II does not affect tRNATyr function. Despite the NLS, most Mod5p is cytosolic. We assessed whether Mod5p sequences cause a karyophilic reporter to be located in the cytosol. By this assay, Mod5p may contain more than one region that functions as cytoplasmic retention and/or nuclear export sequences. Thus, distribution of Mod5p results from the presence/absence of mitochondrial targeting information and sequences antagonistic for nuclear and cytosolic locations. Mod5p is highly conserved; sequences responsible for subcellular distribution appear to reside in "accessory" motifs missing from prokaryotic counterparts.

Alkyl and Aryl Transferases↗
PubMed2004

CTD kinase I is involved in RNA polymerase I transcription.

RNA polymerase II carboxy terminal domain (CTD) kinases are key elements in the control of mRNA synthesis. Yeast CTD kinase I (CTDK-I), is a non-essential complex involved in the regulation of mRNA synthesis at the level of transcription elongation, pre-mRNA 3' formation and nuclear export. Here, we report that CTDK-I is also involved in ribosomal RNA synthesis. We show that CTDK-I is localized in part in the nucleolus. In its absence, nucleolar structure and RNA polymerase I transcription are affected. In vitro experiments show an impairment of the Pol I transcription machinery. Remarkably, RNA polymerase I co-precipitates from cellular extracts with Ctk1, the kinase subunit of the CTDK-I complex. In vitro analysis further demonstrates a direct interaction between RNA polymerase I and Ctk1. The results suggest that CTDK-I might participate in the regulation of distinct nuclear transcriptional machineries, thus playing a role in the adaptation of the global transcriptional response to growth signalling.

Cell Nucleolus↗
PubMed2002

Genetic screen yields mutations in genes encoding all known components of the Escherichia coli signal recognition particle pathway.

We describe the further utilization of a genetic screen that identifies mutations defective in the assembly of proteins into the Escherichia coli cytoplasmic membrane. The screen yielded mutations in each of the known genes encoding components of the E. coli signal recognition particle pathway: ffh, ffs, and ftsY, which encode Ffh, 4.5S RNA, and FtsY, respectively. In addition, the screen yielded mutations in secM, which is involved in regulating levels of the SecA component of the bacterium's protein export pathway. We used a sensitive assay involving biotinylation to show that all of the mutations caused defects in the membrane insertions of three topologically distinct membrane proteins, AcrB, MalF, and FtsQ. Among the mutations that resulted in membrane protein insertion defects, only the secM mutations also showed defects in the translocation of proteins into the E. coli periplasm. Genetic evidence suggests that the S382T alteration of Ffh affects the interaction between Ffh and 4.5S RNA.

ATP-Binding Cassette Transporters↗
PubMed2002

Regulation of estrogen receptor nuclear export by ligand-induced and p38-mediated receptor phosphorylation.

Estrogen receptors are phosphoproteins which can be activated by ligands, kinase activators, or phosphatase inhibitors. Our previous study showed that p38 mitogen-activated protein kinase was involved in estrogen receptor activation by estrogens and MEKK1. Here, we report estrogen receptor-dependent p38 activation by estrogens in endometrial adenocarcinoma cells and in vitro and in vivo phosphorylation of the estrogen receptor alpha mediated through p38. The phosphorylation site was identified as threonine-311 (Thr(311)), located in helix 1 of the hormone-binding domain. The mutation of threonine-311 to alanine did not affect estrogen binding of the receptor but compromised its interaction with coactivators. Suppression of p38 activity or mutation of the site inhibited the estrogen-induced receptor nuclear localization as well as its transcriptional activation by estrogens and MEKK1. The inhibition of the p38 signal pathway by a specific chemical inhibitor blocked the biological activities of estrogens in regulating endogenous gene expression as well as endometrial cancer cell growth. Our studies demonstrate the role of estrogen receptor phosphorylation induced by the natural ligand in estrogen receptor's cellular distribution and its significant contribution to the growth-stimulating activity of estrogens in endometrial cancer cells.

Active Transport, Cell Nucleus↗
PubMed2003

The farnesoid X receptor controls gene expression in a ligand- and promoter-selective fashion.

Farnesoid X receptor (FXR) is a nuclear receptor for bile acids. Ligand activated-FXR regulates transcription of genes to allow feedback control of bile acid synthesis and secretion. There are five major bile acids in humans. We have previously demonstrated that lithocholate acts as an FXR antagonist, and here we show that the other four bile acids, chenodeoxycholate (CDCA), deoxycholate (DCA), cholate (CA), and ursodeoxycholate (UDCA), act as selective FXR agonists in a gene-specific fashion. In an in vitro coactivator association assay, CDCA fully activated FXR, whereas CA partially activated FXR and DCA and UDCA had negligible activities. Similar results were also obtained from a glutathione S-transferase pull-down assay in which only CDCA and the synthetic FXR agonist GW4064 significantly increased the interaction of SRC-1 with FXR. In FXR transactivation assays with a bile salt export pump (BSEP) promoter-driven luciferase construct, bile acids showed distinct abilities to activate the BSEP promoter: CDCA, DCA, CA, and UDCA increased luciferase activity by 25-, 20-, 18-, and 8-fold, respectively. Consistently, CDCA increased BSEP mRNA by 750-fold in HepG2 cells, whereas DCA, CA, and UDCA induced BSEP mRNA by 250-, 75-, and 15-fold, respectively. Despite the partial induction of BSEP mRNA, CA, DCA, and UDCA effectively repressed expression of cholesterol 7alpha-hydroxylase, another FXR target. We further showed that all four bile acids significantly increased FXR protein, suggesting the existence of an auto-regulatory loop in FXR signaling pathways. In conclusion, these results suggest that the binding of each bile acid results in a different FXR conformations, which in turn differentially regulates expression of individual FXR targets.

Cell Line↗
PubMed2001

The human peroxisomal targeting signal receptor, Pex5p, is translocated into the peroxisomal matrix and recycled to the cytosol.

Peroxisomal targeting signals (PTSs) are recognized by predominantly cytosolic receptors, Pex5p and Pex7p. The fate of these PTS receptors following their interactions on the peroxisomal membrane with components of docking and putative translocation complexes is unknown. Using both novel and multiple experimental approaches, we show that human Pex5p does not just bind cargo and deliver it to the peroxisome membrane, but participates in multiple rounds of entry into the peroxisome matrix and export to the cytosol independent of the PTS2 import pathway. This unusual shuttling mechanism for the PTS1 receptor distinguishes protein import into peroxisomes from that into most other organelles, with the exception of the nucleus.

Cell Fractionation↗
PubMed2000

Multiple copies of the Mason-Pfizer monkey virus constitutive RNA transport element lead to enhanced HIV-1 Gag expression in a context-dependent manner.

Retroviral gene expression requires nuclear export and translation of incompletely spliced RNA. In the case of human immunodeficiency virus (HIV), this is facilitated by the viral Rev protein binding to its cognate RNA response element (RRE), while other retroviruses contain constitutive transport elements (CTE) binding to cellular factors. These CTE can substitute for the HIV-1 Rev/RRE system, albeit with reduced efficiency. Here, we show that multimeric copies of the CTE restore HIV-1 protein expression to levels comparable to or higher than Rev/RRE in various cell lines from different species. We suggest that multimerization of export factors is important for CTE function, as reported for Rev. CTE function was not affected when the element was displaced from its natural position close to the poly(A) signal, while insertion of an intron into the 3'-untranslated region (3'-UTR) severely reduced CTE activity. In this case, cytoplasmic RNA degradation was observed, which may be mediated by nonsense-mediated RNA decay. In contrast, Rev-dependent gene expression was insensitive to an intron in the 3'-UTR. Finally, we show that the putative CTE-binding protein RNA helicase A is not specifically translocated into the cytoplasm upon overexpression of CTE-containing RNA.

3' Untranslated Regions↗
PubMed1999

Functional and subcellular changes in the A-kinase-signaling pathway: relation to aromatase and Sgk expression during the transition of granulosa cells to luteal cells.

The responsiveness of granulosa cells to FSH (cAMP) changes as these cells switch from the proliferative stage in growing follicles to the terminally differentiated, nonproliferating stage after LH-induced luteinization. To analyze this transition, two well characterized culture systems were used. 1) Granulosa cells isolated from immature rats were cultured in serum-free medium, a system that permits analysis of dynamic, short-term responses to hormones/cAMP. 2) Granulosa cells from preovulatory (PO) follicles that have been exposed in vivo to surge concentrations of hCG (PO/ hCG) were cultured in medium containing 1% FBS, a system that permits analyses of cells that have undergo irreversible, long-term changes associated with luteinization. To analyze the biochemical basis for the switch in cAMP responsiveness, the localization of A-kinase pathway components was related to the expression of two cAMP target genes, aromatase (CYP19) and serum-and glucocorticoid-induced kinase (Sgk). Components of the A-kinase pathway were analyzed by Western blotting and indirect immunofluorescence using specific antibodies to the C subunit, RIIalpha/beta subunits, CREB (cAMP-regulatory element binding protein), phospho-CREB, CBP (CREB binding protein), and Sgk. Cellular levels of C subunit and CREB were similar in all cell types and hormone treatments. CREB and CBP were nuclear; RIIalpha/beta was restricted to a cytoplasmic basket-like structure. Addition of FSH to immature granulosa cells caused rapid nuclear import of C subunit within 1 h. Nuclear C subunit decreased by 6 h after FSH but could be rapidly reimported to the nucleus by the addition of forskolin at 6, 24, or 48 h. Nuclear C subunit was associated with the rapid but transient increases in phospho-CREB. FSH induced Sgk in a biphasic manner in which the protein was nuclear at 1 h and cytoplasmic at 48 h. Aromatase mRNA was only expressed at 24-48 h after FSH, a pattern that was not altered by phosphodiesterases or phosphatases. In the luteinized (PO/hCG) granulosa cells, immunoreactive C subunit was localized in a punctate pattern in the nucleus as well as to a cytoplasmic basket-like structure, a distribution pattern not altered by forskolin. Aromatase, Sgk, and phospho-CREB were expressed at elevated levels in a non-forskolin-responsive manner. Most notable, both phospho-CREB and Sgk were preferentially localized in a punctate pattern within the cytoplasm and not altered by forskolin. Collectively, these data indicate that when granulosa cells differentiate to luteal cells the subcellular localization (nuclear vs. cytoplasmic) of A-kinase pathway components changes markedly. Thus, either the mechanisms of nuclear import and export or the presence of distinct docking sites (and functions ?) dictate where A-kinase, phospho-CREB and Sgk are localized in granulosa cells compared with the terminally differentiated luteal cells.

Animals↗
PubMed2004

In situ detection and visualization of S-nitrosylated proteins following chemical derivatization: identification of Ran GTPase as a target for S-nitrosylation.

The formation of S-nitrosylated proteins is a nitric oxide-dependent post-translational modification important in signal transduction, yet the in situ detection of S-nitrosylated proteins remains problematic. In this study, we adapted a recently developed biotin derivatization approach to visualize S-nitrosylated proteins in intact cells. This strategy circumvents the use of antibodies directed against S-nitrosocysteine, which may have problematic specificity, due to epitope instability. Endogenous protein S-nitrosylation could be observed in intact cells and in mouse lung sections using fluorophore-conjugated streptavidin and confocal microscopy, and was enhanced by S-nitrosothiols and reduced following treatment with the nitric oxide synthase inhibitor, L-N-monomethyl arginine. Intriguingly, protein S-nitrosylation was detected mainly in the nuclear compartment of cells under baseline conditions and was enhanced when nuclear export was blocked with leptomycin B. We also determined that the small GTPase Ran, a key regulator of nucleocytoplasmic transport, is a target for S-nitrosylation. These findings demonstrate that biotin derivatization is a useful approach to detect S-nitrosylated proteins in situ in cellular compartments or tissues, and will be useful in the assessment of altered S-nitrosylation in pathological conditions.

Animals↗
PubMed2004

The N terminus of the peroxisomal cycling receptor, Pex5p, is required for redirecting the peroxisome-associated peroxin back to the cytosol.

Most newly synthesized peroxisomal matrix proteins are transported to the organelle by Pex5p, a remarkable multidomain protein involved in an intricate network of transient protein-protein interactions. Presently, our knowledge regarding the structure/function of amino acid residues 118 to the very last residue of mammalian Pex5p is quite vast. Indeed, the cargo-protein receptor domain as well as the binding sites for several peroxins have all been mapped to this region of Pex5p. In contrast, structural/functional data regarding the first 117 amino acid residues of Pex5p are still scarce. Here we show that a truncated Pex5p lacking the first 110 amino acid residues (DeltaN110-Pex5p) displays exactly the peroxisomal import properties of the full-length peroxin implying that this N-terminal domain is involved neither in cargo-protein binding nor in the docking/translocation step of the Pex5p-cargo protein complex at the peroxisomal membrane. However, the ATP-dependent export step of DeltaN110-Pex5p from the peroxisomal membrane is completely blocked, a phenomenon that was also observed for a Pex5p version lacking just the first 17 amino acid residues but not for a truncated protein comprising amino acid residues 1-324 of Pex5p. By exploring the unique properties of DeltaN110-Pex5p, the effect of temperature on the import/export kinetics of Pex5p was characterized. Our data indicate that the export step of Pex5p from the peroxisomal compartment (in contrast with its insertion into the organelle membrane) is highly dependent on the temperature.

Adenosine Triphosphatases↗
PubMed2000

14-3-3 proteins: regulation of subcellular localization by molecular interference.

14-3-3 family of proteins plays a key regulatory role in signal transduction, checkpoint control, apoptotic, and nutrient-sensing pathways. 14-3-3 proteins act by binding to partner proteins, and this binding often leads to the altered subcellular localization of the partner. 14-3-3 proteins promote the cytoplasmic localization of many binding partners, including the pro-apoptotic protein BAD and the cell cycle regulatory phosphatase Cdc25C, but they can also promote the nuclear localization of other partners, such as the catalytic subunit of telomerase (TERT). In some cases, 14-3-3 binding has no effect on the subcellular localization of a partner. 14-3-3 may affect the localization of a protein by interfering with the function of a nearby targeting sequence, such as a nuclear localization sequence (NLS) or a nuclear export sequence (NES), on the binding partner.

14-3-3 Proteins↗
PubMed2006

NFATc1 nucleocytoplasmic shuttling is controlled by nerve activity in skeletal muscle.

Calcineurin-NFAT signaling has been shown to control activity-dependent muscle gene regulation and induce a program of gene expression typical of slow oxidative muscle fibers. Following Ca2+-calmodulin stimulation, calcineurin dephosphorylates NFAT proteins and induces their translocation into the nucleus. However, NFAT nuclear translocation has never been investigated in skeletal muscle in vivo. To determine whether NFATc1 nucleocytoplasmic shuttling depends on muscle activity, we transfected fast and slow mouse muscles with plasmids coding for an NFATc1-GFP fusion protein. We found that NFATc1-GFP has a predominantly cytoplasmic localization in the fast tibialis anterior muscle but a predominantly nuclear localization in the slow soleus muscle, with a characteristic focal intranuclear distribution. Two hours of complete inactivity, induced by denervation or anaesthesia, cause NFATc1 export out of the nucleus in soleus muscle fibers, whereas electrostimulation of tibialis anterior with a low-frequency tonic impulse pattern, mimicking the firing pattern of slow motor neurons, causes NFATc1 nuclear translocation. The activity-dependent nuclear import and export of NFATc1 is a rapid event, as visualized directly in vivo by two-photon microscopy. The calcineurin inhibitor cain/cabin1 causes nuclear export of NFATc1 both in normal soleus and stimulated tibialis anterior muscle. These findings support the notion that in skeletal muscle NFATc1 is a calcineurin-dependent nerve activity sensor.

Active Transport, Cell Nucleus↗
PubMed2004

The karyopherin Msn5/Kap142 requires Nup82 for nuclear export and performs a function distinct from translocation in RPA protein import.

Protein transport between the nucleus and cytoplasm requires interactions between nuclear pore complex proteins (nucleoporins) and soluble nuclear transport factors (karyopherins, importins, and exportins). Exactly how these interactions contribute to the nucleocytoplasmic transport of substrates remains unclear. Using a synthetic lethal screen with the nucleoporin NUP1, we have identified a conditional allele of NUP82, encoding an essential nuclear pore complex protein in Saccharomyces cerevisiae. This nup82-3 allele also exhibits synthetic genetic interactions with mutants of the karyopherin MSN5. nup82-3 mutants accumulate the Msn5 export substrate Pho4 within the nucleus at non-permissive temperatures. The nuclear import of the RPA complex subunit Rfa2 is impaired in nup82-3 and in mutants of the karyopherin KAP95, but is not affected by the loss of MSN5. Interestingly, deletion of MSN5 results in retention of Rfa2-GFP within the nucleus under conditions in which it normally diffuses out. These data provide evidence that Nup82 is important for Msn5-mediated nuclear protein export and Kap95-mediated protein import. In addition, Msn5 may play a role independent of import in the localization of Rfa2.

Active Transport, Cell Nucleus↗
PubMed2004

Ligand-dependent activation of the farnesoid X-receptor directs arginine methylation of histone H3 by CARM1.

In this study we demonstrate that the class II nuclear hormone receptor, farnesoid X-receptor (FXR), incorporates histone methyltransferase activity within the gene locus for bile salt export pump (BSEP), a well established FXR target gene that functions as an ATP-dependent canalicular bile acid transporter. This methyltransferase activity is directed specifically to arginine 17 of histone H3. We demonstrate that FXR is directly associated with co-activator-associated arginine methyltransferase 1 (CARM1) activity. Furthermore, we show by chromatin immunoprecipitation that the ligand-dependent activation of the human BSEP locus is associated with a simultaneous increase of FXR and CARM1 occupation. The increased occupation of the BSEP locus by CARM1 also corresponds with the increased deposition of Arg-17 methylation and Lys-9 acetylation of histone H3 within the FXR DNA-binding element of BSEP. Consistent with these findings, CARM1 led to increased BSEP promoter activity with an intact FXR regulatory element, whereas CARM1 failed to transactivate the BSEP promoter with a mutated FXRE. Induction of endogenous BSEP mRNA and Arg-17 methylation by FXR regulatory element ligand, CDCA, requires CARM1 activity. Therefore, histone methylation at Arg-17 by CARM1 is a downstream target of signaling through ligand-mediated activation of FXR. Our studies provide evidence that FXR directly recruits specific chromatin modifying activity of CARM1 necessary for full potentiation of the BSEP locus in vivo.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2005

Translational repression by the cis-acting element of structure-anchored repression (CAESAR) of human ctgf/ccn2 mRNA.

The cis-acting element of structure-anchored repression (CAESAR) is a post-transcriptional regulatory element of gene expression, which is located in the 3'-untranslated region (UTR) of the human ccn2 gene (ctgf/ccn2). In this report, the repression mechanism of CAESAR, as well as the structural requirement, was investigated. Removal of minor stem-loops from CAESAR resulted in proportional attenuation of the repressive function, whereas removal of the single bulge or modification of primary nucleotide sequence did not affect its functionality. In light of functional mechanism, CAESAR exerted no significant effects on stability or nuclear export of the cis-linked mRNA. However, this element significantly interfered with the association of such mRNA on ribosome and slowed down the translation process thereafter in vitro. A translation repression mechanism by RNA secondary structure to determine the basal ctgf/ccn2 expression level was uncovered herein.

3' Untranslated Regions↗