Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “mRNA”

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 487 records · Page 27Linked to original sources
PubMed2006

Identification of the chicken growth hormone-releasing hormone receptor (GHRH-R) mRNA and gene: regulation of anterior pituitary GHRH-R mRNA levels by homologous and heterologous hormones.

GHRH stimulates GH secretion in chickens as in mammals. However, nothing is known about the chicken GHRH receptor (GHRH-R). Here we report the cDNA sequence of chicken GHRH-R. Comparison of the cDNA sequence with the chicken genome localized the GHRH-R gene to chicken chromosome 2 and indicated that the chicken GHRH-R gene consists of 13 exons. Expression of all exons was confirmed by RT-PCR amplification of pituitary mRNA. The amino acid sequence predicted by the GHRH-R cDNA is homologous to that in other vertebrates and contains seven transmembrane domains and a conserved hormone-binding domain. The predicted size of the GHRH-R protein (48.9 kDa) was confirmed by binding of (125)I-GHRH to chicken pituitary membranes and SDS-PAGE. GHRH-R mRNA was readily detected by RT-PCR in the pituitary but not in the hypothalamus, total brain, lung, adrenal, ovary, or pineal gland. Effects of corticosterone (CORT), GHRH, ghrelin, pituitary adenylate cyclase-activating peptide, somatostatin (SRIF), and TRH on GHRH-R and GH gene expression were determined in cultures of chicken anterior pituitary cells. GHRH-R and GH mRNA levels were determined by quantitative real-time RT-PCR. Whereas all treatments affected levels of GH mRNA, only CORT, GHRH, and SRIF significantly altered GHRH-R mRNA levels. GHRH-R gene expression was modestly increased by GHRH and suppressed by SRIF at 4 h, and CORT dramatically decreased levels of GHRH-R mRNA at 72 h. We conclude that adrenal glucocorticoids may substantially impact pituitary GH responses to GHRH in the chicken through modulation of GHRH-R gene expression.

Amino Acid Sequence↗
PubMed1999

Colocalization of neurotensin messenger ribonucleic acid (mRNA) and progesterone receptor mRNA in rat arcuate neurons under estrogen-stimulated conditions.

In the female rat, estrogen and progesterone directly or indirectly regulate the activity of neurotensin (NT)-synthesizing neurosecretory cells located in the hypothalamic arcuate nucleus (ARC). To determine whether these NT neurons are subject to direct regulation by ovarian steroids, estrogen-inducible messenger RNA (mRNA) encoding nuclear progesterone receptor (PR) was used as a cellular marker for nuclear estrogen receptor (ER) as well as PR, and double label in situ hybridization was employed to determine the extent to which NT/neuromedin N mRNA and PR mRNA are colocalized in ARC neurons under estrogen-stimulated conditions. In estradiol-treated ovariectomized rats, approximately 80% of NT/neuromedin N mRNA-expressing cells in sections through the dorsomedial division of the ARC and approximately 60% of such cells in sections through the ventrolateral division of the ARC were found to contain PR mRNA. Depending on the ARC division and rostrocaudal level, double labeled cells accounted for approximately 20-50% of PR mRNA-containing cells. These results indicate that under estrogen-stimulated conditions the majority of NT neurons in the ARC express both PR and ER, as previous studies of this region indicate that estrogen-inducible PR occurs only in cells that also express ER. In the rat, NT neurons appear to be a major ARC cell type subject to direct regulation by estrogen and progesterone.

Animals↗
PubMed2000

Estrogen receptor beta (ERbeta) messenger ribonucleic acid (mRNA) expression within the human forebrain: distinct distribution pattern to ERalpha mRNA.

Estrogen has been shown to influence several brain functions as well as the expression of neuropsychiatric diseases. To date, two estrogen receptor (ER) subtypes have been identified, ERalpha and ERbeta. ERalpha messenger ribonucleic acid (mRNA) distribution in the human forebrain was recently characterized, and the highest expression was found in restricted areas of the amygdala and hypothalamus. However, no information exists with regard to ERbeta mRNA distribution in the human brain. To this end, the anatomical distribution pattern of ERbeta mRNA expression in the human forebrain was investigated in the present study. Overall, the ERbeta mRNA hybridization signal was relatively low, but the most abundant ERbeta mRNA areas were the hippocampal formation (primarily the subiculum), claustrum, and cerebral cortex; expression was also present in the subthalamic nucleus and thalamus (ventral lateral nucleus). In contrast to ERalpha (studied on adjacent brain sections), ERbeta mRNA expression was low in the hypothalamus and amygdala. Based on the revealed anatomical distribution of the human ERbeta gene expression, a putative role for ERbeta in the modulation of cognition, memory, and motor functions is suggested.

Adolescent↗
PubMed1995

Substratum surface topography alters cell shape and regulates fibronectin mRNA level, mRNA stability, secretion and assembly in human fibroblasts.

The regulation of cell shape, fibronectin mRNA level, secretion and assembly by substratum surface topography was investigated in early passage human gingival fibroblasts cultured on titanium-coated smooth or V-shaped grooved substrata produced by micromachining. Cells on grooved surfaces were significantly elongated and orientated along the grooves of the substratum, while cell height, measured using confocal scanning laser microscopy, was approximately 1.5-fold greater than that of cells on smooth surfaces. Northern hybridization analysis revealed that on a per cell basis the grooved surface increased the amounts of fibronectin mRNA/cell approximately 3.5-fold at 16 hours, approximately 1.9-fold at 40 hours and approximately 2.2-fold at 90 hours, while the mRNA levels of the house-keeping gene glyceraldehyde-3-phosphate dehydrogenase (GAPD) were constant. The amounts of secreted fibronectin on the grooved surface were increased approximately 2-fold for all time points. The stability of fibronectin mRNA was also altered by substratum surface topography. The half-life of fibronectin mRNA on smooth surfaces was estimated to be approximately 5 hours, but on the grooved surfaces the half-life of fibronectin mRNA showed a two-phase response: a rapid 60% reduction in the first half-life (t1/2 approximately 2 hours) and a 2.4-fold increase in the second half-life (t1/2 approximately 12 hours) relative to that observed on the smooth surface. The GAPD mRNA half-lives were essentially unaffected by the surface topography of the substrata. The grooved surface was also found to alter the amount of fibronectin assembled into the extracellular matrix, producing a approximately 2-fold increase in the cultures at all time points. It thus appears that substratum surface topography alters cell shape and modulates fibronectin at the transcriptional and post-transcriptional levels, as well as the amount of fibronectin assembled into extracellular matrix. Micromachining, which has the ability to precisely control surface topography over a wide range of dimensions and shapes, appears to be a useful technique in investigating the relationship between cell shape and function.

Adult↗
PubMed1999

Pre-mRNA and mRNA binding of human nuclear DNA helicase II (RNA helicase A).

Nuclear DNA helicase II (NDH II), alternatively named RNA helicase A, seems to function as a pre-mRNA and mRNA binding protein in human cells. Immunofluorescence studies of NDH II gave a highly diffused nucleoplasmic staining that was similar to that of hnRNP A1 but differed from the localization of the RNA splicing factor Sc-35. Upon transcriptional inhibition, NDH II migrated from the nucleus into the cytoplasm. During mitosis, NDH II was released into the cytoplasm during pro- to metaphase, and was gradually recruited back into telophase nuclei. The timing of nuclear import of NDH II at telophase was found to be later than that of hnRNP A1 but paralleled that of Sc-35. At the ultrastructural level, both NDH II and hnRNP A1 were identified within perichromatin ribonucleoparticle fibrils. However, the subnuclear distributions of NDH II and hnRNP A1 were not overlapping. NDH II could be extracted together with poly(A)-containing mRNA from HeLa cell nuclei and, to a much lesser extent, from the cytoplasm. Following transcriptional inhibition, NDH II was preferentially associated with mRNA from the cytosol, which biochemically confirmed the microscopic observations. Although NDH II is mainly a nuclear enzyme, it is apparently not associated with the nuclear matrix, since it could be extracted with 2 M NaCl from DNase I-treated nuclei. Our cellular and biochemical observations strongly suggest that NDH II is a pre-mRNA and mRNA binding protein. Its significant affinity for ssDNA, but not for dsDNA, points to a transient role in DNA binding during the process of transcript formation. According to our model, single-stranded DNA might be necessary to retain NDH II in the nuclear compartment.

Adenosine Triphosphatases↗
PubMed2005

mRNA with a <20-nt poly(A) tail imparted by the poly(A)-limiting element is translated as efficiently in vivo as long poly(A) mRNA.

The poly(A)-limiting element (PLE) is a conserved sequence that restricts the length of the poly(A) tail to <20 nt. This study compared the translation of PLE-containing short poly(A) mRNA expressed in cells with translation in vitro of mRNAs with varying length poly(A) tails. In transfected cells, PLE-containing mRNA had a <20-nt poly(A) and accumulated to a level 20% higher than a matching control without a PLE. It was translated as well as the matching control mRNA with long poly(A) and showed equivalent binding to polysomes. Translation in a HeLa cell cytoplasmic extract was used to examine the impact of the PLE in the context of varying length poly(A) tails. Here the overall translation of +PLE mRNA was less than control mRNA with the same length poly(A), and the PLE did not overcome the effect of a short poly(A) tail. Because poly(A)-binding protein (PABP) is a dominant effector of poly(A)-dependent translation we reasoned excess PABP in our extract might overwhelm PLE regulation of translation. This was confirmed by experiments where PABP was inactivated with poly(rA) or Paip2, and the effect of both treatments was reversed by addition of recombinant PABP. These data indicate that the PLE functionally substitutes for bound PABP to stimulate translation of short poly(A) mRNA.

Animals↗
PubMed1997

The stability of truncated epidermal growth factor receptor mRNA is higher than that of the full-length receptor mRNA in rat hepatoma cells.

Truncated and full-length epidermal growth factor (EGF) receptors are produced in rat liver cells. The truncated EGF receptor mRNA is almost identical to the full-length EGF receptor mRNA except for the lack of a 3' region of the full-length receptor mRNA. To understand the stability of rat EGF receptor mRNAs, we analyzed the expression of EGF receptor mRNAs in the hepatoma cell line, AH66 and liver cells. Ten, 7 and 5 kb full-length and 2.7 kb truncated EGF receptor mRNAs were detected in both of them. The half-lives of the 10 and 2.7 kb EGF receptor mRNAs were determined in AH66 cells using a transcriptional inhibitor, 5,6-dichlororibofuranosylbenzimidazole. The half-lives of the 10 and 2.7 kb mRNAs were 1.2 and 11 h, respectively. These results indicated that the truncated mRNA is 4 times more stable than the full-length mRNA in rat cells. As for the stability, the role of a sequence of 3'-untranslated region of the EGF receptor mRNA was discussed.

Animals↗
PubMed1999

CD28-Mediated regulation of mRNA stability requires sequences within the coding region of the IL-2 mRNA.

Using sequence-tagged genomic reporter constructs, we investigated the contribution of IL-2 sequences to CD28-mediated regulation of mRNA stability. We find that CD28 signaling acts transiently to stabilize the IL-2 mRNA following T cell activation. Such stabilization requires sequences within both exon 2 and the coding region of exon 4. Unexpectedly, CD28 signaling at later times enhances the decay of the IL-2 mRNA. This CD28-dependent decay of IL-2 mRNA requires sequences localized between exon 3 and the stop codon. Our findings demonstrate that the coding region of the IL-2 mRNA contains previously undefined CD28-responsive sequence elements that are critical for the regulation of mRNA stability.

3' Untranslated Regions↗
PubMed2000

[Quantitation of mRNA in micro-samples of the brain by competitive PCR: analysis of expression of interleukin-1 beta mRNA in rat hypothalamus and hippocampus after inflammatory or non-inflammatory stress].

Changes in the expressions of interleukin-1 beta (IL-1 beta) mRNA in the rat brain were investigated during inflammatory or non-inflammatory stress. We utilized competitive reverse transcription PCR (RT-PCR) to quantitate precisely the minute amount of IL-1 beta mRNA in small tissues which were micro-punched out from discrete sites in the brain. Intraperitoneal injection of lipopolysaccharide (100 micrograms/kg) caused a widespread and high elevation of IL-1 beta mRNA in the hypothalamus, hippocampus and cerebral cortex. Immobilization stress significantly increased IL-1 beta mRNA only in the hypothalamus, when examined in the brain block samples, which reached a peak 30 minutes after the start of stress. However, examination of the small tissues punched out from discrete sites in the brain revealed a profound elevation of IL-1 beta mRNA in the CA1 region of the hippocampus and in all the hypothalamic nuclei examined 30 minutes after the start of immobilization stress, but not in the CA3 region and the dentate gyrus or cerebral cortex. The method shown in this report proved to be useful and may be applied to quantify the low amount of mRNA in the small areas in the brain.

Animals↗
PubMed2001

[Apoptosis of pancreatic acinar and expression of TNF-alpha mRNA, IL-10 mRNA in rats with acute pancreatitis].

OBJECTIVE: To investigate the apoptosis of pancreatic acinar and the expression of TNF-alpha mRNA, IL-10 mRNA in pancreatic tissue of rats with acute pancreatitis. METHODS: The model of acute edematous pancreatitis(AEP) was established in 20 rats and that of acute necrotizing pancreatits(ANP) in another 20 by injection of sodium taurocholate into the pancreatic duct. Another 10 normal rats were used as controls. At 12 hours after the induction of pancreatitis, 10 rats in each group were sacrificed. Serum and pancreatic TNF-alpha and IL-10 levels were measured. The expression of TNF-alpha and IL-10 mRNA in pancreas was detected and the apoptotic rate of pancreatic acinar determined. RESULTS: The apoptotic rate of pancreatic acinar in normal, AEP and ANP groups was 2.98%, 17.29% and 8.39%, respectively. TNF-alpha and IL-10 levels increased after the induction of acute pancreatitis. The level of TNF-alpha was lower while that of IL-10 higher in AEP group than in ANP group. Transcription level of TNF-alpha mRNA in ANP group and that of IL-10 mRNA in AEP group were upregulated. CONCLUSIONS: The transcription levels of TNF-alpha and IL-10 mRNA in pancreatic tissue of rats with acute pancreatitis are positively correlated with their levels in serum and pancreas, suggesting that the pancreas is the organ to release cytokines. The apoptotic rate of pancreatic acinar is negatively correlated with the severity of disease and apoptosis may be a benign response to pancreatic injury.

Acute Disease↗
PubMed2000

[Expression of transforming growth factor-beta 1 mRNA and osteopontin mRNA in UMR-106 cells under mechanical stimulation].

OBJECTIVE: To investigate the effects of the mechanical stretching on the expression of osteopontin (OPN) mRNA and transforming growth factor-beta 1 (TGF beta 1) mRNA in a rat osteosarcoma cell line (UMR-106), and to unveil the cellular mechanism of mechanical force-induced bone remodeling. METHODS: An apparatus was designed and fabricated by which force was loaded onto the cultured cells in vitro. Digoxin-labeled cDNA probes were used for in situ hybridization in combination with image analysis technique to relatively quantify the intensities of the hybridization signals. RESULTS: Various magnitudes and durations of the mechanical stretching did exert different influences on the intensities of the mRNAs' expression. Of all the combinations, the low tension/frequency group showed the most remarkable alteration of TGF-beta 1, as increased from 0.0899 to 0.1756 (P < 0.01). Some putative relations lay between the expressions of the OPN mRNA and the TGF-beta 1 mRNA. CONCLUSION: The mechanical stretching can inevitably influence the expression of OPN mRNA and TGF-beta 1 mRNA. The beneficial alteration obtained in using low tension/frequency action mode suggests and verifies the use of relatively constant and light force to move teeth in clinical orthodontics.

Animals↗
PubMed2001

[IL-1 beta mRNA and TNF-alpha mRNA expression in gingival tissues of patients with adult periodontitis].

OBJECTIVE: The aim of this study was to examine interleukin-1 beta (IL-1 beta) mRNA and tumor necrosis factor alpha (TNF-alpha) mRNA expression in gingival tissues of patients with adult periodontitis. METHODS: A total of 19 patients, including 10 patients with adult periodontitis and 9 healthy individuals as the control, were evaluated for were selected for evaluating IL-1 beta mRNA and TNF-alpha mRNA expression, using reverse transcription polymerase chain reaction (RT-PCR) technique. RESULTS: The relative amount of IL-1 beta mRNA expression of gingival samples from patients with adult periodontitis (0.819 +/- 0.045) (P < 0.01) was much higher than that from the normal control (0.306 +/- 0.087) (P < 0.01). The relative amount of TNF-alpha mRNA expression, gingival samples from AP patients (0.696 +/- 0.098) was also much higher than that from the normal control (0) (P < 0.01). CONCLUSION: As the inflammatory and bone absorption mediators, IL-1 beta and TNF-alpha might play important roles in the pathogenesis and development of adult periodontitis.

Adolescent↗
PubMed1992

CTLA-4 and CD28 mRNA are coexpressed in most T cells after activation. Expression of CTLA-4 and CD28 mRNA does not correlate with the pattern of lymphokine production.

Ag-presenting cells provide at least two distinct signals for T cell activation. T cell receptor-dependent stimulation is provided by presentation of a specific peptide Ag in association with MHC molecules. In addition, APC also supply costimulatory signals required for T cell activation that are neither Ag- nor MHC restricted. One such costimulatory signal is mediated via the interaction of B7 on APC with the CD28 receptor on T cells. Recently, CTLA-4 has been shown to be a second B7 receptor on T cells. In the present report, we have examined the expression of CD28 and CTLA-4 on a panel of resting and activated normal T cell subsets and T cell clones by RNA blot analysis in an attempt to determine whether their expression defines reciprocal or overlapping subsets. CD28 was detected in resting T cells, whereas CTLA-4 was not. After stimulation with PHA and PMA for 24 h, CTLA-4 mRNA was expressed in both the CD4+ and CD8+ subsets as well as in CD28+ T cells. We examined 37 human and six murine T cell clones that had been previously characterized for their cytokine production. After activation, CTLA-4 and CD28 mRNA were coexpressed in 36 of 37 human T cell clones and all six murine T cell clones. These included T cells of CD4+8-, CD4-8+, and CD4-8- phenotypes as well as clones with Th1 and Th2 cytokine profiles. In contrast, CD28 but not CTLA-4 mRNA was detected in leukemic T cell lines and myelomas. CTLA-4 and B7 mRNA but not CD28 mRNA was detected in two long term HTLV-I-transformed T cell lines. These data demonstrate that CD28 and CTLA-4 mRNA are coexpressed in most activated T cells and T cell clones, providing evidence that they do not define reciprocal subsets. Moreover, they are consistent with the hypothesis that B7 transmits its signal through a single receptor, CD28, on resting T cells, and multiple receptors, CD28 and CTLA-4, on activated T cells.

Abatacept↗
PubMed2005

[Expression and pathological implication of transforming growth factor-beta1 mRNA and endothelin-1 mRNA in intraacinar pulmonary arterioles of congenital heart disease accompanied with pulmonary hypertension].

OBJECTIVE: To study the expression and pathological implication of transforming growth factor-1 (TGF-1) and endothelin-1 (ET-1) in intraacinar pulmonary arterioles of children with congenital heart disease and pulmonary hypertension (HP). METHODS: Forty-one children with left-to-right shunt congenital heart disease were studied including 25 cases of HP (group A), 16 cases without HP (group B) and 10 children without congenital heart disease as the contols (group C). Expression of TGF-beta1 mRNA and ET-1 mRNA in intraacinar pulmonary arteriolar (IAPA) was studied using in-situ hybridization and image pattern analysis of their absorption values (A value). Changes of the intraacinar arterioles and lung tissue were studied by elastic fiber staining and electronic microscopy respectively. RESULTS: (1) There was a significant difference in the amount of intraacinar pulmonary arterioles (partial-muscular and muscular) counted in either group A or B in comparing with that of group C (F values 149.96 and 142.01 respectively, P < 0.01); (2) Electronic microscopy demonstrated endothelial proliferation of the small arteries, thickening of arteriolar wall, increased density of collagen fibers at adventitia and increased thickness of the capillary basal membrane; (3) The A value of TGF-beta1 mRNA expressed in the pulmonary arterioles of groups A and B by in-situ hybridization were 0.1988 +/- 0.0498 and 0.1098 +/- 0.0428 respectively, however, the expression was weak in group C (A value: 0.0578 +/- 0.0096). There were all significant between each two groups (F = 45.95, P < 0.01). The expression of ET-1 mRNA was markedly increased as well in the endothelial cells of pulmonary arterioles in both groups A and B, with A values of 0.1692 +/- 0.0205 and 0.1004 +/- 0.0140 respectively, whereas the expression was weak in group C (A value of 0.0746 +/- 0.0119). There were all significant between each two groups (F = 139.996, P < 0.01). CONCLUSIONS: The number of intraacinar pulmonary partial-muscular and muscular arterioles in patients with left-to-right shunt congenital heart defect is drastically increased, along with marked restructuring of the pulmonary vasculatures. In addition, there seems a correlation present between the overexpression of TGF-beta1 mRNA and ET-1 mRNA in intraacinar pulmonary arterioles and the occurrence of pulmonary hypertension in patients with congenital heart disease.

Child↗
PubMed2005

[Expression of mRNA levels of thymidylate synthase, dihydropyrimidine dehydrogenase, and orotate phosphoribosyltransferase of colorectal cancer--relationships among mRNA levels in association with response to 5-FU based treatment].

We semiquantificated the mRNA levels of thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), and orotate phosphoribosyltransferase(OPRT) from the frozen tissue of colorectal cancer, in order to examine the relationships among these enzymes and the efficacy for 5-fluorouracil (FU)-based treatment in terms of the combinations of the expression levels of these enzymes. There were weak and positive relationships among TS mRNA expression and OPRT mRNA expression or DPD mRNA expression, while there was no significant relationship between DPD mRNA expression and OPRT mRNA expression (n = 112). In 39 patients who received 5-FU-based chemotherapy with evaluable lesions, patients with low TS expression (n = 23) showed a higher response rate (52%) as compared to those with high TS expression (13%, p = 0.02). Patients with low TS, low DPD, or high DPD expression tended to show a higher response rate (50%) than those with the other combinations (26%, p = 0.09). In addition, all of the responders with only one favorable factor (n = 4) were associated with low TS or low DPD expression. In conclusion, low TS expression followed by low DPD expression is important to predict the efficacy of 5-FU-based treatment for colorectal cancer. However, it may be of little significance to semiquantify the expression of OPRT.

Adult↗
PubMed2006

[Expression and significance of toll like receptor 4 mRNA and nuclear factor-kappaB p50 mRNA in human normal nasal mucosa after stimulation by lipopolysaccharide].

OBJECTIVE: To investigate the expression and significance of Toll like receptor (TLR)4 mRNA and nuclear factor (NF)-kappaB p50 mRNA in human normal nasal mucosal cell before and after stimulation by LPS. METHODS: The tissue was obtained from 15 normal middle turbinates (without rhinosinusitis). Every tissue was cultured in vitro, divided into 2 specimens. LPS was added into 15 specimens as LPS group and not added into other 15 specimens as control group. The pathomorphological characters of nasal mucosal cells were observed under optical microscope after stimulation by LPS. The expression of TLR4 mRNA and NF-kappaB p50 mRNA in normal human nasal mucosal cells were evaluated by in situ hybridization. RESULTS: Normal mucociliary agglutinated and mucosal cells were enlarged after stimulation by LPS; The expression of TLR4 mRNA in LPS group was higher than control group obviously. Their average density of light was 1.283 +/- 0.027 in LPS group while 0.538 +/- 0.038 in control group, and there was statistical significance between the two groups (t = 1.761, P < 0.05). The expression of NF-kappaB p50 mRNA was higher than control group obviously, and expressed in cellular nucleus predominantly. Their average density of light was 1. 668 +/- 0.037 in LPS group while 0. 372 +/- 0.052 in control group, and there was statistical significance between the two groups (t = 2. 624, P < 0. 01). CONCLUSIONS: LPS can activate the NF-kappaB p50 of human nasal mucosal cells through TLR4, and it may play some roles in stimulating and damage effect induced by LPS in nasal mucosal cells.

Adult↗
PubMed1991

Identification of sequences within the murine granulocyte-macrophage colony-stimulating factor mRNA 3'-untranslated region that mediate mRNA stabilization induced by mitogen treatment of EL-4 thymoma cells.

Phorbol esters (TPA) and concanavalin A (ConA) are known to induce granulocyte-macrophage colony-stimulating factor (GM-CSF) production in murine thymoma EL-4 cells by mRNA stabilization. The role of the 3'-untranslated region (3'-UTR) in GM-CSF mRNA stabilization induced by TPA and ConA in EL-4 cells was examined by transfection studies using chloramphenicol acetyltransferase (CAT) constructions. The GM-CSF 3'-UTR contains a 63-nucleotide region at its 3' end with repeating ATTTA motifs which is responsible for mRNA degradation in a variety of cell types (Shaw, G., and Kamen, R. (1986) Cell 46, 659-666). We produced constructs containing most of the GM-CSF 3'-UTR (303 nucleotides, pRSV-CATgm) or the 3'-terminal AT-rich region (116 nucleotides, pRSV-CATau) and measured CAT enzyme activity and CAT mRNA after transient transfection into EL-4 and NIH 3T3 cells. Low levels of CAT activity were seen in both cells with either plasmid compared with levels of CAT activity obtained with pRSV-CAT. TPA treatment caused an approximately 10-fold increase in CAT activity and mRNA in EL-4 cells transfected with pRSV-CATgm. No increases were seen in EL-4 cells transfected with pRSV-CATau or pRSV-CAT. No response to TPA was detected in transfected NIH 3T3 cells, indicating that the response to TPA is relatively cell-specific. There was no increase in CAT activity after ConA treatment in EL-4 or NIH 3T3 cells transfected with any of the constructs suggesting that the GM-CSF 3'-UTR lacks elements that can respond alone to ConA. Nuclear run-on and actinomycin D chase experiments in EL-4 cells showed that TPA induces CAT activity via mRNA stabilization. By linker-substitution mutagenesis we show that TPA inducibility depends on a 60-nucleotide region of the 3'-UTR whose 5' end is located 160 nucleotides upstream of the 5' end of the AU-rich region.

Animals↗
PubMed1991

The splicing pattern of fibronectin mRNA changes during chondrogenesis resulting in an unusual form of the mRNA in cartilage.

Chondrogenesis, the differentiation of mesenchyme into cartilage, results in a change in composition of the extracellular matrix. The cartilage matrix contains several unique components, including type II collagen and chondroitin sulfate proteoglycan; it also contains fibronectin, a glycoprotein that mediates the interaction of cells with their matrix. We show that chick cartilage fibronectin mRNA contains an unusual pattern of alternatively spliced exons. Specifically, it contains exon IIIB but does not contain exon IIIA whereas fibronectin mRNA from mesenchyme contains both exons IIIB and IIIA. Thus the splicing pattern of the fibronectin mRNA must change from B+A+ to B+A- during chondrogenesis. Most fibronectin mRNA in other mesenchymal tissues contains exon IIIA but little exon IIIB (B-A+). Culturing of chondrocytes (cartilage-producing cells) results in loss of exon IIIB from fibronectin mRNA (B-A-). Manipulation of culture conditions to produce more adhesive chondrocytes (treatment with hyaluronidase, transformation with Rous sarcoma virus, and treatment with retinoic acid) increases the amount of fibronectin mRNA containing exon IIIA. These results suggest that exon IIIB may mediate the interactions of chondrocytes with the unique components of the cartilage matrix and exon IIIA may play a role in chondrocyte adhesion.

Animals↗