Biomedical subjects

Jinshui Fan

Publications and source records attributed to Jinshui Fan.

At least 19 recordsLinked to original sources

PubMed2026

Human Immunodeficiency Virus-Associated Proteomic Signature of Myocardial Fibrosis and Incident Heart Failure.

BACKGROUND: People with human immunodeficiency virus (HIV) (PWH) are at higher risk of myocardial fibrosis and subsequent heart failure (HF) compared to people without HIV (PWOH). Mechanisms underlying this risk and its specificity to PWH are unclear. METHODS: We measured 2594 proteins in plasma obtained concurrently with cardiovascular magnetic resonance imaging among 342 PWH and PWOH. We estimated associations with HIV serostatus and myocardial fibrosis (elevated extracellular volume fraction [ECV] ≥30% among women, ≥28% among men) using multivariable regression. Among an independent community-based cohort, we estimated associations between the identified signature and time to incident HF. RESULTS: Mean age of participants was 55 (standard deviation [SD], 6) years, 25% were female, 61% were PWH (88% on antiretroviral therapy, 74% with undetectable HIV RNA), and 52% had elevated ECV. We identified 39 proteins and 1 cluster of 42 proteins that were higher among PWH versus PWOH and positively associated with elevated ECV, independent of risk factors (false discovery rate <0.05). Among an independent cohort of 3223 PWOH (mean age, 68 [SD, 9] years; 52% female; 118 incident HF cases over a mean of 9.8 [SD, 1.4] years), we found that this protein cluster and 34 of 39 individual proteins were associated with time to incident HF. This signature was statistically enriched for T-cell activation, tumor necrosis factor signaling, ephrin signaling, and tissue maintenance and repair. CONCLUSIONS: We identified an HIV-related proteomic signature associated with myocardial fibrosis regardless of HIV serostatus and that predicted incident HF among the general population. Our results identify several novel associations related to specific immune processes that may contribute to risk of myocardial fibrosis and subsequent HF among both PWH and PWOH.

Humans↗

PubMed2006

WRN exonuclease activity is blocked by DNA termini harboring 3' obstructive groups.

Reactive oxygen species, generated either by cellular respiration or upon exposure to environmental agents such as ionizing radiation (IR), attack DNA to form a variety of oxidized base and sugar modifications. Accumulation of oxidative DNA damage has been associated with age-related disease as well as the aging process. Single-strand breaks harboring oxidative 3' obstructive termini, e.g. 3' phosphates and 3' phosphoglycolates, must be removed prior to DNA repair synthesis or ligation. In addition, 3' tyrosyl-linked protein damage, resulting from therapeutic agents such as camptothecin (CPT), must be processed to initiate repair. Several nucleases participate in DNA repair and the excision of 3' obstructive ends. As the protein defective in the segmental progeroid Werner syndrome (WRN) possesses 3'-5' exonuclease activity, and Werner syndrome cells are hypersensitive to IR and CPT, we examined for WRN exonuclease activity on 3' blocking lesions. Moreover, we compared side-by-side the activity of four prominent human 3'-5' exonucleases (WRN, APE1, TREX1, and p53) on substrates containing 3' phosphates, phosphoglycolates, and tyrosyl residues. Our studies reveal that while WRN degrades 3' hydroxyl containing substrates in a non-processive manner, it does not excise 3' phosphate, phosphoglycolate, or tyrosyl groups. In addition, we found that APE1 was most active at excising 3' blocking termini in comparison to the disease-related exonucleases TREX1, WRN, and p53 under identical physiological reaction conditions, and that TREX1 was the most powerful 3'-5' exonuclease on undamaged oligonucleotide substrates.

Cells, Cultured↗

PubMed2006

Pyrrolidine dithiocarbamate inhibits interleukin-6 signaling through impaired STAT3 activation and association with transcriptional coactivators in hepatocytes.

Interleukin (IL)-6 is a proinflammatory cytokine that has been implicated in the expression of acute phase plasma proteins and hepatic insulin resistance through activation of the JAK/STAT3 pathway. Although previous studies have demonstrated that pyrrolidine dithiocarbamate (PDTC) exerts protection against inflammatory responses, its role in the regulation of IL-6 receptor signaling remains unclear. Here we show that treatment of cultured HepG2 hepatoma cells with PDTC inhibits IL-6-stimulated tyrosine phosphorylation and subsequent nuclear translocation of STAT3 in a dose- and time-dependent fashion. No inhibition of JAK-1 activity was observed. To provide insight into PDTC signaling, we constructed a conditionally active STAT3 by fusing it with the ligand binding domain of the estrogen receptor (STAT3-ER). In the presence of 4-hydroxytamoxifen STAT3-ER was translocated in the nucleus of HepG2 cells in a phosphorylation-independent manner, and treatment with PDTC mitigated the response. Although STAT3 coprecipitated with heat-shock protein 90 (Hsp90) in control cells, coprecipitation of the two proteins was greatly reduced after PDTC treatment or after exposure to geldanamycin, an Hsp90 inhibitor. As a result there was a decrease in IL-6-induced association of STAT3 with the transcriptional coactivators FOXO1a and C/EBPbeta together with significant reduction in the expression of SOCS-3 protein and that of two major acute phase plasma proteins. Importantly, treatment of HepG2 cells and a primary culture of rat hepatocytes with PDTC restored insulin responsiveness that was abrogated by IL-6. These studies are consistent with the ability of PDTC to down-regulate IL-6-induced STAT3 activation by altering the stability of STAT3-Hsp90 complex.

Active Transport, Cell Nucleus↗

PubMed2006

En masse nascent transcription analysis to elucidate regulatory transcription factors.

Despite exhaustively informing about steady-state mRNA abundance, DNA microarrays have been used with limited success to identify regulatory transcription factors (TFs). The main limitation of this approach is that altered mRNA stability also strongly governs the patterns of expressed genes. Here, we used nuclear run-on assays and microarrays to systematically interrogate changes in nascent transcription in cells treated with the topoisomerase inhibitor camptothecin (CPT). Analysis of the promoters of coordinately transcribed genes after CPT treatment suggested the involvement of TFs c-Myb and Rfx1. The predicted CPT-dependent associations were subsequently confirmed by chromatin immunoprecipitation assays. Importantly, after RNAi-mediated knockdown of each TF, the CPT-elicited induction of c-Myb- and/or Rfx1-regulated mRNAs was diminished and the overall cellular response was impaired. The strategies described here permit the successful identification of the TFs responsible for implementing adaptive gene expression programs in response to cellular stimulation.

Binding Sites↗

PubMed2005

Nucleotide sequence and DNA secondary structure, as well as replication protein A, modulate the single-stranded abasic endonuclease activity of APE1.

A major role of the multifunctional human Ape1 protein is to incise at apurinic/apyrimidinic (AP) sites in DNA via site-specific endonuclease activity. This nuclease function has been well characterized on double-stranded (ds) DNA substrates, where the complementary strand provides a template for subsequent base excision repair events. Recently, Ape1 was found to incise efficiently at AP sites positioned within the single-stranded (ss) regions of various biologically relevant DNA configurations. The studies within indicated that the ss endonuclease activity of Ape1 is poorly active on ss AP site-containing polyadenine or polythymine oligonucleotides, suggesting a requirement for some form of DNA secondary structure for efficient cleavage. Computational, footprinting, and biochemical analyses indicated that the nature of the secondary structure and the proximity of the AP site influence Ape1 incision efficiency significantly. Replication protein A (RPA), the major ssDNA-binding protein in mammalian cells, was found to bind ss AP-DNA with similar affinity as unmodified ssDNA and ds AP-DNA with lower affinity. Consistent with their known relative DNA binding affinities, RPA blocks/inhibits the ss, but not ds, AP endonuclease function of Ape1. Moreover, RPA inactivates Ape1 incision activity at an AP site within the ss region of a fork duplex, but not a transcription-like bubble intermediate. The data herein suggested a model whereby RPA selectively suppresses the nontemplated ss cleavage activity of Ape1 in vivo, particularly at sites of ongoing replication/recombination, by coating the ssDNA.

Base Sequence↗

PubMed2005

Control of gene expression during T cell activation: alternate regulation of mRNA transcription and mRNA stability.

BACKGROUND: Microarray technology has become highly valuable for identifying complex global changes in gene expression patterns. The effective correlation of observed changes in gene expression with shared transcription regulatory elements remains difficult to demonstrate convincingly. One reason for this difficulty may result from the intricate convergence of both transcriptional and mRNA turnover events which, together, directly influence steady-state mRNA levels. RESULTS: In order to investigate the relative contribution of gene transcription and changes in mRNA stability regulation to standard analyses of gene expression, we used two distinct microarray methods which individually measure nuclear gene transcription and changes in polyA mRNA gene expression. Gene expression profiles were obtained from both polyA mRNA (whole-cell) and nuclear run-on (newly transcribed) RNA across a time course of one hour following the activation of human Jurkat T cells with PMA plus ionomycin. Comparative analysis revealed that regulation of mRNA stability may account for as much as 50% of all measurements of changes in polyA mRNA in this system, as inferred by the absence of any corresponding regulation of nuclear gene transcription activity for these groups of genes. Genes which displayed dramatic elevations in both mRNA and nuclear run-on RNA were shown to be inhibited by Actinomycin D (ActD) pre-treatment of cells while large numbers of genes regulated only through altered mRNA turnover (both up and down) were ActD-resistant. Consistent patterns across the time course were observed for both transcribed and stability-regulated genes. CONCLUSION: We propose that regulation of mRNA stability contributes significantly to the observed changes in gene expression in response to external stimuli, as measured by high throughput systems.

Cell Nucleus↗

PubMed2005

Protein-protein interactions and posttranslational modifications in mammalian base excision repair.

Base excision repair (BER) averts the cytotoxic and mutagenic effects of most endogenously produced DNA damage, including lesions that arise spontaneously due to the intrinsic instability of DNA or modifications that are formed from reactions with intracellular chemicals, such as reactive oxygen species and alkylating agents. Defects in the BER process have been associated with cancer susceptibility and neurodegenerative disorders. In its most simplistic form, BER can be fully reconstituted with a minimum of four human proteins and is completed in just five sequential steps: (i) excision of an inappropriate base by a DNA glycosylase (e.g., uracil DNA glycosylase); (ii) incision of the DNA backbone immediately adjacent to the resulting abasic site by apurinic/apyrimidimic endonuclease 1; (iii) removal of the 5'-abasic terminal fragment, and (iv) repair synthesis to fill the gap by DNA polymerase beta; and (v) ligation to seal the remaining nick by DNA ligase 1 or a complex of DNA ligase 3 and X-ray repair cross-complementing 1. However, BER can involve the participation of other proteins as well, such as alternative DNA polymerases or one of several nonessential "auxiliary" factors. In addition, BER operates most efficiently when specific protein-protein coordination occurs. Furthermore, several BER protein activities have been shown to be regulated by posttranslational modification, and some of the physical protein interactions link BER to other DNA transaction pathways. In this review, we summarize the current state of the emerging complexities of mammalian BER, focusing on the growing number of reported protein-protein interactions and posttranslational modifications.

Animals↗

PubMed2005

Oxidative damage in telomeric DNA disrupts recognition by TRF1 and TRF2.

The ends of linear chromosomes are capped by protein-DNA complexes termed telomeres. Telomere repeat binding factors 1 and 2 (TRF1 and TRF2) bind specifically to duplex telomeric DNA and are critical components of functional telomeres. Consequences of telomere dysfunction include genomic instability, cellular apoptosis or senescence and organismal aging. Mild oxidative stress induces increased erosion and loss of telomeric DNA in human fibroblasts. We performed binding assays to determine whether oxidative DNA damage in telomeric DNA alters the binding activity of TRF1 and TRF2 proteins. Here, we report that a single 8-oxo-guanine lesion in a defined telomeric substrate reduced the percentage of bound TRF1 and TRF2 proteins by at least 50%, compared with undamaged telomeric DNA. More dramatic effects on TRF1 and TRF2 binding were observed with multiple 8-oxo-guanine lesions in the tandem telomeric repeats. Binding was likewise disrupted when certain intermediates of base excision repair were present within the telomeric tract, namely abasic sites or single nucleotide gaps. These studies indicate that oxidative DNA damage may exert deleterious effects on telomeres by disrupting the association of telomere-maintenance proteins TRF1 and TRF2.

DNA↗

PubMed2005

Stability regulation of mRNA and the control of gene expression.

Microarray technology has become highly valuable for identifying complex global changes in gene expression patterns. Standard techniques measure changes in total cellular poly(A) mRNA levels. The assumption that changes in gene expression as measured by these techniques are directly and well correlated with changes in rates of new gene synthesis form the basis of attempts to connect coordinated changes in gene expression with shared transcription regulatory elements. Yet systematic attempts at this approach remain difficult to demonstrate convincingly. One reason for this difficulty may result from the intricate convergence of both transcriptional and mRNA turnover events which, together, directly influence steady-state mRNA levels. Recent technical advances have led to the successful scale-up and application of nuclear run-on procedures directly to microarrays. This development has allowed a gene-by-gene comparison between new gene synthesis in the nucleus and measured changes in total cellular polyA mRNA. Results from these studies have begun to challenge the strict interpretation of changes in gene expression measured by conventional microarrays as being closely correlated with changes in mRNA transcription rate, but rather they tend to support the significant expansion of the role played by changes in mRNA stability regulation to standard analyses of gene expression. Gene expression profiles obtained from both polyA mRNA (whole-cell) and nuclear run-on (newly transcribed) RNA across a time course of one hour following the activation of human Jurkat T cells with PMA plus ionomycin revealed that regulation of mRNA stability may account for as much as 50% of all measurements of changes in total cellular polyA mRNA in this system. Stability regulation was inferred by the absence of corresponding regulation of nuclear gene transcription activity for groups of genes strongly regulated at the whole cell level and which were also resistant to inhibition by Actinomycin D pre-treatment. Consistent patterns across the time course were observed for both transcribed and stability-regulated genes. It is proposed that the regulation of mRNA stability in response to external stimuli contributes significantly to observed changes in gene expression as measured by high throughput systems.

Cell Line, Tumor↗

PubMed2004

Prostaglandin A2-mediated stabilization of p21 mRNA through an ERK-dependent pathway requiring the RNA-binding protein HuR.

Treatment with the stress agent prostaglandin A2 (PGA2) induces expression of the cyclin-dependent kinase inhibitor p21. Here, we present evidence that p21 expression increases through PGA2-triggered stabilization of the p21 mRNA and further show that these events require the mitogen-activated protein (MAP) kinase ERK. Binding experiments using either endogenous p21 mRNA or in vitro-labeled p21 transcripts revealed a specific PGA2-dependent association of the p21 mRNA with the RNA-binding protein HuR. Interestingly, although inhibition of the ERK pathway did not prevent the PGA2-triggered increase in cytoplasmic HuR, it did impair the formation of endogenous and in vitro [HuR-p21 mRNA] complexes and further prevented the PGA2-mediated stabilization of the p21 mRNA, suggesting that ERK-mediated events were required for binding HuR to the p21 mRNA and preventing its decay. RNA interference-based knockdown of HuR abundance further served to demonstrate the contribution of HuR-mediated p21 mRNA stabilization toward enhancing p21 expression after PGA2 treatment. Collectively, our results indicate that PGA2 stabilizes the p21 mRNA through an ERK-independent increase in cytoplasmic HuR levels and an ERK-dependent association of HuR with the p21 mRNA.

3' Untranslated Regions↗

PubMed2004

XRCC1 co-localizes and physically interacts with PCNA.

X-ray Repair Cross Complementing 1 (XRCC1) is thought to function as a scaffolding protein in both base excision repair and single-strand break repair (SSBR), since it interacts with several proteins participating in these related pathways and has no known enzymatic activity. Moreover, studies indicate that XRCC1 possesses discrete G1 and S phase-specific functions. To further define the contribution of XRCC1 to DNA metabolism, we determined the in vivo localization pattern of this protein and searched for novel protein interactors. We report here that XRCC1 co-localizes with proliferating cell nuclear antigen (PCNA) at DNA replication foci, observed exclusively in the S phase of undamaged HeLa cells. Furthermore, fluorescence resonance energy transfer (FRET) analysis and co-immunoprecipitation indicate that XRCC1 and PCNA are in a complex and likely physically interact in vivo. In vitro biochemical analysis demonstrated that these two proteins associate directly, with the interaction being mediated by residues between amino acids 166 and 310 of XRCC1. The current evidence suggests a model where XRCC1 is sequestered via its interaction with PCNA to sites of DNA replication factories to facilitate efficient SSBR in S phase.

Cell Extracts↗

PubMed2004

Global mRNA stabilization preferentially linked to translational repression during the endoplasmic reticulum stress response.

The stability of mRNAs undergoing translation has long been a controversial question. Here, we systematically investigate links between mRNA turnover and translation during the endoplasmic reticulum (ER) stress response, a process during which protein synthesis is potently regulated. cDNA array-based approaches to assess the stability and translational status of each mRNA were devised. First, ER stress-triggered changes in mRNA stability were studied by comparing differences in steady-state mRNA levels with differences in gene transcription. Second, changes in translational status were monitored by studying ER stress-induced shifts in the relative distribution of each mRNA along sucrose gradients. Together, the array-derived data reveal complex links between mRNA stability and translation, with all regulatory groups represented: both stabilized and destabilized mRNAs were found among translationally induced as well as translationally suppressed mRNA collections. Remarkably, however, the subset of stabilized mRNAs was prominently enriched in translationally suppressed transcripts, suggesting that ER stress was capable of causing the stabilization of mRNAs associated with a global reduction in protein synthesis. The cDNA array-based approach described here can be applied to global analyses of mRNA turnover and translation and can serve to investigate subsets of mRNAs subject to joint posttranscriptional control.

Blotting, Northern↗

PubMed2004

Global analysis of HuR-regulated gene expression in colon cancer systems of reducing complexity.

HuR, a protein that binds to target mRNAs and can enhance their stability and translation, is increasingly recognized as a pivotal regulator of gene expression during cell division and tumorigenesis. We sought to identify collections of HuR-regulated mRNAs in colon cancer cells by systematic, cDNA array-based assessment of gene expression in three systems of varying complexity. First, comparison of gene expression profiles among tumors with different HuR abundance revealed highly divergent gene expression patterns, and virtually no changes in previously reported HuR target mRNAs. Assessment of gene expression patterns in a second system of reduced complexity, cultured colon cancer cells expressing different HuR levels, rendered more conserved sets of HuR-regulated mRNAs. However, the definitive identification of direct HuR target mRNAs required a third system of still lower complexity, wherein HuR-RNA complexes immunoprecipitated from colon cancer cells were subject to cDNA array hybridization to elucidate the endogenous HuR-bound mRNAs. Comparison of the transcript sets identified in each system revealed a strikingly limited overlap in HuR-regulated mRNAs. The data derived from this systematic analysis of HuR-regulated genes highlight the value of low-complexity, biochemical characterization of protein-RNA interactions. More importantly, however, the data underscore the broad usefulness of integrated approaches comprising systems of low complexity (protein-nucleic acid) and high complexity (cells, tumors) to comprehensively elucidate the gene regulatory events that underlie biological processes.

Animals↗

PubMed2003

Role of the RNA-binding protein HuR in colon carcinogenesis.

Immunohistochemical analysis of paired tumor and normal tissue specimens revealed that the expression and cytoplasmic abundance of the RNA-binding protein HuR increased with malignancy, particularly in colon carcinomas. Interventions to modulate HuR expression in human RKO colon cancer cells altered gene expression profiles and identified beta-catenin mRNA as a novel HuR target. Subcutaneous injection of HuR-overexpressing RKO cells into nude mice produced significantly larger tumors than those arising from control populations; conversely, RKO cells expressing reduced HuR through small interference RNA- or antisense HuR-based approaches developed significantly more slowly. We propose that HuR-regulated target mRNA expression contributes to colon cancer growth. Our results suggest a pivotal function for HuR in colon carcinogenesis.

Animals↗

PubMed2003

Characterization of fragmented mitochondrial ribosomal RNAs of the colorless green alga Polytomella parva.

We have identified previously in mitochondrial DNA of the colorless, chlorophycean, green algal taxon, Polytomella parva, potential coding regions for four small subunit (SSU) and eight large subunit (LSU) rRNA fragments. In this study with P.parva, we isolated RNA from a mitochondrial-enriched preparation, characterized the 12 mitochondrial rRNA transcripts by either northern blot analysis or chemical sequencing and performed secondary structure modeling of the SSU and LSU rRNA sequences. The results show the following features about the mitochondrial SSU and LSU rRNAs of P.parva: (i) they are considerably shorter than their homologs from other green algae, although the main domains typical of conventional rRNAs are conserved; (ii) the rRNA fragmentation pattern is most similar to that of Chlamydomonas reinhardtii among green algae that have been characterized; (iii) three nucleotides are missing from the normally highly conserved GTPase center of the LSU rRNA; and (iv) post-transcriptional modification of the 3'-terminal region of the SSU rRNA is unusual in that it has the 'eubacterial' 3-methyluridine (corresponding to m(3)U at Escherichia coli 16S rRNA position 1498) but lacks the more highly conserved modifications at two adjacent A residues (corresponding to N(6),N(6)-dimethyladenosine at E.coli 16S rRNA positions 1518 and 1519). This is the first report of the characterization by direct sequencing of fragmented mitochondrial rRNAs from a green alga.

Base Sequence↗

PubMed2003

Role of HuR in skeletal myogenesis through coordinate regulation of muscle differentiation genes.

In this report, we investigate the role of the RNA-binding protein HuR during skeletal myogenesis. At the onset of myogenesis in differentiating C2C12 myocytes and in vivo in regenerating mouse muscle, HuR cytoplasmic abundance increased dramatically, returning to a predominantly nuclear presence upon completion of myogenesis. mRNAs encoding key regulators of myogenesis-specific transcription (myogenin and MyoD) and cell cycle withdrawal (p21), bearing AU-rich regions, were found to be targets of HuR in a differentiation-dependent manner. Accordingly, mRNA half-lives were highest during differentiation, declining when differentiation was completed. Importantly, HuR-overexpressing C2C12 cells displayed increased target mRNA expression and half-life and underwent precocious differentiation. Our findings underscore a critical function for HuR during skeletal myogenesis linked to HuR's coordinate regulation of muscle differentiation genes.

3' Untranslated Regions↗

PubMed2003

Influence of the RNA-binding protein HuR in pVHL-regulated p53 expression in renal carcinoma cells.

A recent analysis of gene expression in renal cell carcinoma cells led to the identification of mRNAs whose translation was dependent on the presence of the von Hippel-Lindau (VHL) tumor suppressor gene product, pVHL. Here, we investigate the finding that pVHL-expressing RCC cells (VHL(+)) exhibited elevated levels of polysome-associated p53 mRNA and increased p53 protein levels compared with VHL-defective (VHL(-)) cells. Our findings indicate that p53 translation is specifically heightened in VHL(+) cells, given that (i) p53 mRNA abundance in VHL(+) and VHL(-) cells was comparable, (ii) p53 degradation did not significantly influence p53 expression, and (iii) p53 synthesis was markedly induced in VHL(+) cells. Electrophoretic mobility shift and immunoprecipitation assays to detect endogenous and radiolabeled p53 transcripts revealed that the RNA-binding protein HuR, previously shown to regulate mRNA turnover and translation, was capable of binding to the 3' untranslated region of the p53 mRNA in a VHL-dependent fashion. Interestingly, while whole-cell levels of HuR in VHL(+) and VHL(-) cells were comparable, HuR was markedly more abundant in the cytoplasmic and polysome-associated fractions of VHL(+) cells. In keeping with earlier reports, the elevated cytoplasmic HuR in VHL(+) cells was likely due to the reduced AMP-activated kinase activity in these cells. Demonstration that HuR indeed contributed to the increased expression of p53 in VHL(+) cells was obtained through use of RNA interference, which effectively reduced HuR expression and in turn caused marked decreases in p53 translation and p53 abundance. Taken together, our findings support a role for pVHL in elevating p53 expression, implicate HuR in enhancing VHL-mediated p53 translation, and suggest that VHL-mediated p53 upregulation may contribute to pVHL's tumor suppressive functions in renal cell carcinoma.

3' Untranslated Regions↗

PubMed2003

von Hippel-Lindau protein-mediated repression of tumor necrosis factor alpha translation revealed through use of cDNA arrays.

Based on evidence that the von Hippel-Lindau (VHL) tumor suppressor protein is associated with polysomes and interacts with translation regulatory factors, we set out to investigate the potential influence of pVHL on protein translation. To this end, renal cell carcinoma (RCC) cells that either lacked pVHL or expressed pVHL through stable transfection were used to prepare RNA from cytosolic (unbound) and polysome-bound fractions. Hybridization of cDNA arrays using RNA from each fraction revealed a subset of transcripts whose abundance in polysomes decreased when pVHL function was restored. The tumor necrosis factor alpha (TNF-alpha) mRNA was identified as one of the transcripts that preferentially associated with polysomes in pVHL-deficient cells. Additional evidence that the TNF-alpha mRNA was a target of translational repression by pVHL was obtained from reporter gene assays, which further revealed that pVHL's inhibitory influence on protein synthesis occurred through the TNF-alpha 3'-untranslated region. Our findings uncover a novel function for the pVHL tumor suppressor protein as regulator of protein translation.

3' Untranslated Regions↗