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PubMed1995

Increased apoB100 mRNA in inbred strains of mice by estrogen is caused by decreased RNA editing protein mRNA.

Estrogen administration to rats diminishes all apoproteins and lipoproteins from plasma. In contrast, some inbred strains of mice raise their plasma apoB and LDL levels by more than 2-fold (Srivastava et al, 1993, Eur. J. Biochem. 216, 527-538). Further studies with 13 inbred strains of mice given 3 micrograms beta-estradiol/g body weight/day for 5 consecutive days suggest that some mouse strains increased their apoB and LDL levels and some did not. To examine the mechanism of influence of genetic factors on apoB regulation, two strains, C57L and C57BL, that increased their VLDL- and LDL-cholesterol, and 2 strains, BALB and C3H, that did not, were chosen. Estrogen increased plasma apoB levels selectively in the strains C57L and C57BL, termed as 'responders,' but did not change in BALB and C3H, termed as 'non-responders.' One of the mechanisms for increased plasma apoB levels could be through increased production of apoB-containing particles. This possibility was investigated. ApoB and REPR mRNA were quantified by RNase protection assay, and apoB-100 mRNA by apoB mRNA editing assay. Hepatic apoB mRNA increased by 30% in 'non-responders,' but decreased by 20% in the 'responders.' However, apoB-100 mRNA increased relative to apoB-48 mRNA in all the 4 strains by 50%. The mRNA for RNA editing protein (REPR) decreased in all strains, suggesting that apoB-100 mRNA increased as a result of decreased apoB mRNA editing activity. These results suggest that:(a) modulation of apoB mRNA by estrogen was strain-specific;(b) increased apoB100 mRNA in inbred strains of mice were caused by decreased apoB mRNA editing activity; and (c) the differences in the plasma apoB levels among 'responder' and 'nonresponder' strains of mice occur through mechanisms other than the apoB mRNA editing.

APOBEC-1 Deaminase↗
PubMed2000

Upregulation of BDNF mRNA and trkB mRNA in the nigrostriatal system and in the lesion site following unilateral transection of the medial forebrain bundle.

We have performed unilateral transection of the medial forebrain bundle (MFB) and studied BDNF mRNA and trkB mRNA levels at different postlesion times in the nigrostriatal system by means of in situ hybridization. BDNF mRNA levels were transiently induced in the substantia nigra pars compacta at 1 day postaxotomy. The disposition of BDNF mRNA expressing cells at this postlesion time in substantia nigra mimicked that of the dopaminergic neurons expressing the mRNA for the dopamine transporter. TrkB mRNA levels remained unaltered in the ventral mesencephalon at the different postlesion times examined-1 to 14 days. In contrast, trkB mRNA levels were significantly induced in the striatum at the longer postlesion time examined-14 days-when all neurodegenerative events are completed. It is becoming apparent that nigral BDNF mRNA levels are anterogradely transported to its target tissue in striatum. However, following axotomy, the lesion site represents a second potential target for BDNF action. Consequently, we also analyzed the pattern of mRNA expression for BDNF and trkB at the lesion site where dopaminergic axons are disconnected. There, we found notable inductions of both BDNF mRNA and trkB mRNA levels at 4 days postaxotomy. BDNF mRNA expressing cells were confined at the site of axotomy, which coincided precisely to that showing induction of trkB mRNA. Altogether, our results anticipate promising trophic roles of BNDF in the injured nigrostriatal system.

Animals↗
PubMed1998

Levels of trkA and BDNF mRNA, but not NGF mRNA, fluctuate across the estrous cycle and increase in response to acute hormone replacement.

Recent studies suggest that hormone replacement therapy can help to reduce the risk and severity of Alzheimer's-related dementia in postmenopausal women. We have hypothesized that these effects are due, in part, to the ability for estrogen and progesterone to enhance hippocampal function, as well as the functional status of cholinergic projections to the hippocampus and cortex, by influencing the expression of specific neurotrophins and neurotrophin receptors. In the present study, quantitative in situ hybridization techniques were used to determine whether the levels of trkA mRNA in the basal forebrain, and nerve growth factor (NGF) mRNA and brain-derived neurotrophic factor (BDNF) mRNA in the hippocampus, are significantly affected by physiological changes in circulating gonadal steroids. Gonadally intact animals were sacrificed at different stages of the estrous cycle and ovariectomized animals were sacrificed at different times following the administration of either estrogen or estrogen plus progesterone. In gonadally intact animals, significant fluctuations in the levels of trkA mRNA in the medial septum (MS), and BDNF mRNA in regions CA1 and CA3/4 of the hippocampus, were detected across the estrous cycle. In animals that received hormone replacement, a significant increase (30.4%) in trkA mRNA was detected in the MS of animals sacrificed 24 h following estrogen administration. Levels of trkA mRNA in the MS declined to control levels over the next 48 h; however, a single injection of progesterone administered 48 h after estradiol appeared to prevent any further decline in trkA mRNA over the next 24 h. In addition, significant increases in BDNF mRNA were detected in the dentate granule cell layer (73.4%), region CA1 (28. 1%), and region CA3/4 (76.9%) of animals sacrificed 53 h after receiving estrogen and 5 h after receiving progesterone. No significant changes in trkA mRNA were detected in the nucleus basalis magnocellularis, and no significant changes in NGF mRNA were detected in the hippocampus. These data demonstrate that levels of trkA mRNA in the MS, and BDNF mRNA in the hippocampus, are affected by physiological changes in the levels of circulating gonadal steroids and are elevated in response to acute hormone replacement. The relevance of these effects to the ability for estrogen replacement to enhance cholinergic activity and hippocampal function, and thereby reduce the risk and severity of Alzheimer's-related dementia in postmenopausal women, is discussed.

Animals↗
PubMed1998

Similar response to simvastatin in patients heterozygous for familial hypercholesterolemia with mRNA negative and mRNA positive mutations.

In patients heterozygous for familial hypercholesterolemia, the low-density lipoprotein (LDL) cholesterol lowering effect of beta-hydroxy-beta-methylglutaryl coenzyme A reductase inhibitors may depend on the nature of the mutation in the LDL receptor gene. To test this hypothesis, we compared the response to simvastatin, 20 mg daily for 9 weeks, between heterozygous carriers of functionally different classes of mutations, i.e. mRNA negative or mRNA positive mutations. Out of 116 consecutive, unrelated patients with familial hypercholesterolemia, 27 patients were selected for molecular analyses: 14 patients with mRNA negative and 13 with mRNA positive mutations. Before simvastatin treatment, patients with mRNA negative mutations had higher levels of LDL cholesterol, lower levels of high-density lipoprotein (HDL) cholesterol and significantly more often tendon xanthomas, compared to patients with mRNA positive mutations. Simvastatin reduced the mean fasting LDL cholesterol levels to a similar percentage in the mRNA negative and mRNA positive patients (37, 36%, respectively, 95% CI of difference--8 to 5%, P = 0.2). This effect was similar to the 37% decrease observed in our total series of patients with familial hypercholesterolemia (n = 116). The increase in mean concentration of HDL cholesterol was greater in the mRNA negative group than in the mRNA positive group (16, 0%, respectively, 95%, CI of difference 8-25%, P = 0.002) independent of the response of total triglycerides to simvastatin. The percentage LDL cholesterol lowering response varied among multiple carriers of the same mutation, even in the case of mRNA negative mutations. We conclude that the percentage LDL lowering response to simvastatin treatment was similar in patients with mRNA negative and mRNA positive mutations. Moreover, variation of this response within multiple carriers of the same mutation suggests an influence of additional factors.

Anticholesteremic Agents↗
PubMed2003

Reduced serum insulin-like growth factor (IGF) I is associated with reduced liver IGF-I mRNA and liver growth hormone receptor mRNA in food-deprived cattle.

Nutritional deprivation decreases blood insulin-like growth factor I (IGF-I) concentrations in a variety of species. In this study, we explored the underlying mechanism by determining the effects of food deprivation on the levels of total IGF-I mRNA and total growth hormone receptor (GHR) mRNA, as well as the levels of individual IGF-I mRNA variants and GHR mRNA variants in the liver of steers. Food deprivation for nearly 3 d decreased the levels of serum IGF-I by 63% (P < 0.01), and this decrease was associated with a 75% decrease (P < 0.01) in total IGF-I mRNA in the liver. The food deprivation-induced decrease in liver total IGF-I mRNA was associated with an equivalent decrease in the levels of both class 1 and class 2 IGF-I mRNA. In addition to IGF-I mRNA, food deprivation also decreased the levels of total GHR mRNA in the liver (P < 0.05), and this decrease was associated with a decrease in the liver expression of GHR mRNA variants 1C3 (P < 0.05) and 1A (P = 0.08). Food deprivation did not affect the levels of two other major GHR mRNA variants, 1B and 1C2, in the liver. These results demonstrate that the food deprivation-induced decrease in circulating IGF-I in steers is associated with a coordinate decrease in the expression of different IGF-I mRNA variants and a specific decrease in the expression of GHR mRNA variants 1C3 and 1A in the liver.

Animals↗
PubMed2000

Corticosteroids decrease mRNA levels of SERCA pumps, whereas they increase sarcolipin mRNA in the rat diaphragm.

1. In order to explore the potential role of the sarcoplasmic-endoplasmic reticulum Ca2+-ATPase (SERCA)-type pumps and of their modulators phospholamban (PLB) and sarcolipin (SLN) in the functional alterations of the diaphragm induced by corticosteroid treatment, expression of SERCA, PLB and SLN was assessed by RT-PCR in the diaphragm of rats treated daily for 5 days either with triamcinolone (80 mg kg-1, n = 8) or with saline (control; 0.6 ml, n = 8). 2. Triamcinolone treatment reduced the normalised overall amount of all SERCA mRNA in diaphragm by 70 % compared to controls (P < 0.05). This reduction was accounted for by a relatively larger decrease in the SERCA1 mRNA (-69 %, P < 0.05) whilst the decrease in SERCA2 mRNA (-49 %, P = 0.09) did not reach statistical significance. As a result the relative proportion of SERCA2 mRNA was increased from 43 +/- 7 % in control diaphragm to 52 +/- 4 % after triamcinolone treatment (P < 0.05). 3. Only the adult isoform of SERCA1 (i.e. SERCA1a) mRNA was found in the diaphragm of the 15-week-old control rats. Furthermore, triamcinolone treatment resulted in reduced levels of SERCA2a (-40 %, P < 0.05) and increased levels of SLN mRNA (+100 %, P < 0.05), while the decrease in PLB mRNA (-31 %, P = 0.277) did not reach statistical significance. SERCA1b, SERCA2b and SERCA3 mRNA levels fell below the detection limit in the diaphragm of both control and triamcinolone-treated rats. 4. Compared to control diaphragm, control rat heart showed a relatively high PLB/(SERCA1 + SERCA2) mRNA ratio of 7.88 while this ratio amounted only to 0.16 in control extensor digitorum longus (EDL) muscle. Remarkably, the SLN/(SERCA1 + SERCA2) mRNA ratio in normal cardiac muscle (0.96) was nearly the same as in diaphragm, but in EDL it amounted to only 0.05 that in diaphragm. This indicates the very low expression of SLN in rat EDL. 5. These data reveal that considerable alterations in SERCA mRNA levels accompany the functional changes seen in diaphragm after corticosteroid treatment. The relatively larger decrease in SERCA1 mRNA is in agreement with the selective type II fibre atrophy previously observed in the diaphragm of triamcinolone-treated rats, but the magnitude of SERCA alterations is more pronounced than expected on the basis of the structural changes in the diaphragm. The increase in SLN mRNA levels may represent a compensatory mechanism.

Adrenal Cortex Hormones↗
PubMed2005

Interleukin-18 (IL-18) mRNA expression and localization of IL-18 mRNA-expressing cells in the mouse uterus.

Interleukin-18 (IL-18) belongs to the interleukin-1 family and was identified as an interferon-gamma inducing factor. We investigated IL-18 mRNA-expressing cells in the mouse uterus. By RNase protection assay, IL-18 mRNA and alpha subunit of IL-18 receptor mRNA were detected in the uterus. In the uterus, IL-18 mRNA levels increased during sexual maturation. In situ hybridization analysis demonstrated IL-18 mRNA-expressing cells in the mouse uterus of different ages. At 21 days of age, IL-18 mRNA-expressing cells were detected in the luminal epithelial cells and stromal cells although the IL-18 mRNA signal was weak. At 42 days of age, IL-18 mRNA signal was mainly detected in the stromal cells located near the myometrium, and in some of the luminal and glandular epithelial cells. In the uterus of 63-day-old adult mice, a strong hybridization signal for IL-18 mRNA was detected at estrus, but was weak at diestrus. IL-18 mRNA was mainly detected in the glandular epithelial cells and stromal cells. The effect of estradiol-17beta (E(2)) on IL-18 mRNA-expressing cells in the uterus was examined in ovariectomized mice. In oil-treated mice IL-18 mRNA signal was localized in luminal epithelial cells and stromal cells, while in E(2)-treated mice IL-18 mRNA signal was localized in stromal cells alone. These results suggest that the mouse uterus has an IL-18 system, and IL-18 exerts a physiological role within the uterus in a paracrine manner, and that IL-18 gene expression is regulated by estrogen.

Age Factors↗
PubMed2003

[Expression of eotaxin mRNA and TNF-alpha mRNA in lung tissues of sensitized mice and modulation by anti-inflammatory drugs].

OBJECTIVE: To establish determination methods of eotaxin mRNA and TNF-alpha mRNA expression in the lung tissue of mice. METHODS: Eotaxin mRNA and TNF-alpha mRNA expressions were determined by semi-quantitative RT-PCR. The functional implications of eotaxin mRNA and TNF-alpha mRNA expression were examined by detecting the numbers of total leucocytes and eosinophils in bronchoalveolar lavage fluid(BALF). RESULT: Eotaxin mRNA and TNF-alpha mRNA expression in lung tissue total numbers of leucocyte and numbers of eosinophil in BALF increased in sensitized mice compared with those in normal mice. Dexamethasone significantly but did not inhibit eotaxin mRNA and TNF-alpha mRNA expressions, and eosinophil infiltration in the lungs of the sensitized mice. A compound preparation of traditional Chinese medicine inhibited eotaxin mRNA and eosinophil infiltration, influenced TNF-alpha mRNA expression. CONCLUSION: Increased eotaxin mRNA expression in lung tissue is associated with eosinophil infiltration in BALF, which indicates that the methods of semi-quantitative RT-PCR may be useful to the study of the mechanism of antiasthmatic medicine.

Animals↗
PubMed2002

Hypoxia may increase rat insulin mRNA levels by promoting binding of the polypyrimidine tract-binding protein (PTB) to the pyrimidine-rich insulin mRNA 3'-untranslated region.

BACKGROUND: Recent reports identify the 3'-UTR of insulin mRNA as crucial for control of insulin messenger stability. This region contains a pyrimidine-rich sequence, which is similar to the hypoxia-responsive mRNA-stabilizing element of tyrosine hydroxylase. This study aimed to determine whether hypoxia affects insulin mRNA levels. MATERIALS AND METHODS: Rat islets were incubated at normoxic or hypoxic conditions and with or without hydrogen peroxide and a nitric oxide donor. Insulin mRNA was determined by Northern hybridization. Islet homogenates were used for electrophoretic mobility shift assay with an RNA-oligonucleotide, corresponding to the pyrimidine-rich sequence of the 3'-UTR of rat insulin I mRNA. The expression of reporter gene mRNA, in islets transfected with reporter gene constructs containing the wild-type or mutated insulin mRNA pyrimidine-rich sequences, was measured by semiquantitive RT-PCR. RESULTS: Insulin mRNA was increased in response to hypoxia. This was paralleled by increased binding of the polypyrimidine tract-binding protein (PTB) to the pyrimidine-rich sequence of the 3'-UTR of insulin mRNA, which was counteracted by hydrogen peroxide. The reporter gene mRNA level containing the wild-type binding site was not increased in response to hypoxia, but mutation of the site resulted in a destabilization of the mRNA. CONCLUSIONS: The complete understanding of different diabetic conditions requires the elucidation of mechanisms that control insulin gene expression. Our data show that hypoxia may increase insulin mRNA levels by promoting the binding of PTB to the insulin mRNA 3'-UTR. Hydrogen peroxide abolishes the hypoxic effect indicating involvement of reactive oxygen species and/or the redox potential in the oxygen-signaling pathway.

3' Untranslated Regions↗
PubMed2007

Dynamic association with polysomes during P19 neuronal differentiation and an untranslated-region-dependent translation regulation of the tau mRNA by the tau mRNA-associated proteins IMP1, HuD, and G3BP1.

Regulation of mRNA translation is a key step in mediating neuronal polarity during differentiation, insofar as neuronal polarity is partially determined by local translation of specific mRNA molecules as dendrites and axons are emanating. The multiplicity of mRNA-binding proteins in neurons plays an essential role in controlling mRNA translation. These proteins are associated with ribosomes and translation factors, thereby regulating both temporally and spatially the translation process. In a previous study, we have shown an association among the tau mRNA-binding proteins HuD, IMP1, and G3BP1 with translating polysomes in P19 neurons. In the present study, we determined the dynamics of the association among G3BP1, IMP1, and HuD with polysomes through P19 neuronal differentiation as well as the functional effect of these proteins on tau mRNA translation. We show a novel, differentiation-dependent association of these proteins with polysomes. In addition, we show a strong, negative effect on translation of the tau mRNA by IMP1, G3BP1, and HuD proteins in HEK-293 cells. To our knowledge this is the first observation of a direct translational role of G3BP1 for any mRNA and the first report of a translation inhibition by IMP1 and HuD on the tau mRNA in a cell system. The translation inhibition is shown to be mediated by the tau mRNA 3'untranslated regions (UTRs), thus giving a new, translational role for these sequences, which were previously implicated in mRNA stabilization. We also define a novel mechanism for IMP1 binding to tau mRNA, which suggests a conformational binding, which is not sequence dependent.

Animals↗
PubMed1996

Growth hormone (GH) status regulates GH receptor and GH binding protein mRNA in a tissue- and transcript-specific manner but has no effect on insulin-like growth factor-I receptor mRNA in the rat.

The effect of growth hormone-deficiency (GHD) and treatment with recombinant bovine GH (bGH) or human IGF-I (hIGF-I) for 10 days on the expression of GH receptor (GHR), GH binding protein (GHBP) and of insulin-like growth factor-I receptor (IGF-IR) mRNA was examined using dw/dw and normal Lewis rats. Hepatic GHR and GHBP mRNA expression was significantly lower in dw/dw rats in comparison to Lewis rats (P < 0.01) while specific 125I-bGH binding to hepatic microsomal membranes was significantly higher (P < 0.01), suggesting a reduction in hepatic GHR turnover with GHD. Treatment with bGH reduced hepatic specific 125I-bGH binding in dw/dw rats, but had no effect in Lewis rats. Treatment with hIGF-I increased hepatic specific 125I-bGH binding in Lewis rats. Hepatic GHR and GHBP mRNA expression was not changed by bGH or hIGF-I treatment, suggesting that differences in hepatic specific 125I-bGH binding may be due to posttranscriptional mechanisms. GHBP mRNA expression was higher in kidney, heart, and muscle of dw/dw rats in comparison to Lewis rats (P < 0.01), while GHR mRNA abundance was not changed. Treatment of dw/dw rats with hIGF-I or bGH resulted in a coordinate reduction of GHR and GHBP mRNAs in kidney (P < 0.01). IGF-IR mRNA was not detected in liver and despite reduced plasma IGF-I levels and IGF-I mRNA expression IGF-IR mRNA abundance was not changed in nonhepatic tissues by GHD. Our data suggest that changes in plasma IGF-I levels and local IGF-I mRNA do not influence IGF-IR mRNA expression, while GHR and GHBP mRNA expression in different rat tissues are regulated independently. The increased nonhepatic GHBP mRNA expression with GHD suggests that nonhepatic GHBP may have an important physiological function distinct from that of GHBP in liver or in plasma.

Animals↗
PubMed2000

Vigilin binding selectively inhibits cleavage of the vitellogenin mRNA 3'-untranslated region by the mRNA endonuclease polysomal ribonuclease 1.

In Xenopus, estrogen induces the stabilization of vitellogenin mRNA and the destabilization of albumin mRNA. These processes correlate with increased polysomal activity of a sequence-selective mRNA endonuclease, PMR-1, and a hnRNP K homology-domain RNA-binding protein, vigilin. Vigilin binds to a region of the vitellogenin mRNA 3'-untranslated region (3'-UTR) implicated in estrogen-mediated stabilization. The vigilin-binding site in the vitellogenin B1 mRNA 3'-UTR contains two consensus PMR-1 cleavage sites. The availability of purified PMR-1 and recombinant vigilin made it possible to test the hypothesis that RNA-binding proteins interact with cis-acting elements to stabilize target mRNAs by blocking cleavage by site-specific mRNA endonucleases. Vigilin binds to the vitellogenin mRNA 3'-UTR site with at least 30-fold higher affinity than it exhibits for the albumin mRNA segment containing the mapped PMR-1 cleavage sites. This differential binding affinity correlates with differential in vitro susceptibility of the protein-RNA complexes to cleavage by PMR-1. Whereas recombinant vigilin has no detectable protective effect on PMR-1 cleavage of albumin mRNA, it retards in vitro cleavage of the vitellogenin mRNA 3'-UTR by purified PMR-1. The PMR-1 sites in the vitellogenin mRNA 3'-UTR are functional because they are readily cleaved in vitro by purified PMR-1. These results provide direct evidence for differential susceptibility to endonuclease-mediated mRNA decay resulting from the differential affinity of a RNA-binding protein for cis-acting stability determinants.

3' Untranslated Regions↗
PubMed2001

The major mRNA-associated protein YB-1 is a potent 5' cap-dependent mRNA stabilizer.

mRNA silencing and storage play an important role in gene expression under diverse circumstances, such as throughout early metazoan development and in response to many types of environmental stress. Here we demonstrate that the major mRNA-associated protein YB-1, also termed p50, is a potent cap-dependent mRNA stabilizer. YB-1 addition or overexpression dramatically increases mRNA stability in vitro and in vivo, whereas YB-1 depletion results in accelerated mRNA decay. The cold shock domain of YB-1 is responsible for the mRNA stabilizing activity, and a blocked mRNA 5' end is required for YB-1-mediated stabilization. Significantly, exogenously added YB-1 destabilizes the interaction of the cap binding protein, eIF4E, with the mRNA cap structure. Conversely, sequestration of eIF4E from the cap increases the association of endogenous YB-1 with mRNA at or near the cap, and significantly enhances mRNA stability. These data support a model whereby down-regulation of eIF4E activity or increasing the YB-1 mRNA binding activity or concentration in cells activates a general default pathway for mRNA stabilization.

Animals↗
PubMed2004

Growth-regulated expression and G0-specific turnover of the mRNA that encodes URH49, a mammalian DExH/D box protein that is highly related to the mRNA export protein UAP56.

URH49 is a mammalian protein that is 90% identical to the DExH/D box protein UAP56, an RNA helicase that is important for splicing and nuclear export of mRNA. Although Saccharomyces cerevisiae and Drosophila express only a single protein corresponding to UAP56, mRNAs encoding URH49 and UAP56 are both expressed in human and mouse cells. Both proteins interact with the mRNA export factor Aly and both are able to rescue the loss of Sub2p (the yeast homolog of UAP56), indicating that both proteins have similar functions. UAP56 mRNA is more abundant than URH49 mRNA in many tissues, although in testes URH49 mRNA is much more abundant. UAP56 and URH49 mRNAs are present at similar levels in proliferating cultured cells. However, when the cells enter quiescence, the URH49 mRNA level decreases 3-6-fold while the UAP56 mRNA level remains relatively constant. The amount of URH49 mRNA increases to the level found in proliferating cells within 5 h when quiescent cells are growth-stimulated or when protein synthesis is inhibited. URH49 mRNA is relatively unstable (T(1/2) = 4 h) in quiescent cells, but is stabilized immediately following growth stimulation or inhibition of protein synthesis. In contrast, there is much less change in the content or stability of UAP56 mRNA following growth stimulation. Our observations suggest that in mammalian cells, two UAP56-like RNA helicases are involved in splicing and nuclear export of mRNA. Differential expression of these helicases may lead to quantitative or qualitative changes in mRNA expression.

ATP-Binding Cassette Transporters↗
PubMed1993

Levels of corticotropin-releasing hormone messenger ribonucleic acid (mRNA) in the hypothalamic paraventricular nucleus and proopiomelanocortin mRNA in the anterior pituitary during late gestation in fetal sheep.

CRH regulates POMC gene expression and subsequent ACTH biosynthesis and release. In sheep, the preterm rise in fetal plasma ACTH commences at approximately 125 days gestation (dGA; 147 dGA = term), preceding the initiation of adrenocortical steroidogenesis. We hypothesized that an increase in CRH expression in the hypothalamic paraventricular nucleus (PVN) and POMC expression in the anterior pituitary in the late gestation sheep fetus may precede adrenal cortex maturation. Fetal sheep were obtained at 105-107 (n = 4), 128-130 (n = 5), and 138-140 (n = 4) dGA. Hypothalami were cryosectioned and subjected to in situ hybridization for ovine CRH mRNA. In all dGA groups, expression of CRH mRNA was observed throughout the rostrocaudal extent of the fetal PVN. The midrostral region of the fetal PVN where the dorsal and ventral divisions of the rostral PVN merge to form a single structure was selected for quantification. The number of copies of CRH probe hybridized per micron 3 were determined to estimate the quantity of hybridized CRH mRNA; the mean estimated CRH mRNA copy number per micron 3 midrostral PVN were 0.064 +/- 0.012 (105-107 dGA), 0.237 +/- 0.048 (128-130 dGA), and 0.108 +/- 0.034 (138-140 dGA; mean +/- SEM copies per micron 3 PVN). CRH mRNA signal significantly increased between 105-107 and 128-130 dGA (P < or = 0.05); 138-140 dGA levels of mRNA were not different from either 105-107 or 128-140 dGA levels. Regional variation in CRH mRNA levels were observed within the midrostral PVN between groups; at 138-140 dGA, a population of lateral midrostral PVN neurons maintain CRH mRNA levels greater than 105-107 dGA (P < 0.05), similar to those at 128-130 dGA. Fetal anterior pituitary RNA was subjected to Northern analysis for POMC mRNA. POMC mRNA levels in fetal anterior pituitaries were 14.1 +/- 2.2 (105-107 dGA), 28.9 +/- 10.9 (128-130 dGA), and 43.2 +/- 6 (138-140 dGA; mean +/- SEM arbitrary units). A significant increase (P < or = 0.05) was observed at 138-140 dGA compared to levels at 105-107 dGA. We conclude CRH mRNA levels in the fetal PVN increase coincident with increased POMC gene expression and the late gestation rise in fetal plasma ACTH. We speculate that a neuroendocrine stimulus at the fetal PVN may precipitate increased levels of CRH mRNA, initiating the maturation of the fetal hypothalamic-hypophyseal-adrenal axis, thus inducing the events of labor and delivery in sheep.

Adrenocorticotropic Hormone↗
PubMed2005

[Relationship between bFGF mRNA and MMP-9 mRNA expression in gastric carcinoma and their clinicopathological features as well as patients survival].

OBJECTIVE: To investigate the mRNA expression of bFGF and MMP-9 in gastric carcinomas and to find their correlation with tumor microvascular density (MVD), invasion, metastasis and patients survival. METHODS: In situ hybridization and immunohistochemistry technique were used to test the expression of bFGF mRNA and MMP-9 mRNA and protein of CD34 in 105 specimens of gastric carcinoma. RESULTS: In situ hybridization revealed that the positive rates of bFGF mRNA and MMP-9 mRNA were 60.95 and 58.1%, respectively; The mean MVD (46.09 +/- 11.52, 43.75 +/- 13.41 piece/0.72 mm(2)) in tumors with bFGF mRNA and MMP-9 mRNA positive expression was significantly higher than that (29.41 +/- 12.47; 33.45 +/- 13.92 piece/0.72 mm(2)) in tumors with their negative expression, respectively; The positive expression rates of bFGF and MMP-9 mRNA were correlated to invasion depth (r(s) = 0.211, P = 0.031; r(s) = 0.335, P = 0.001, respectively), growing pattern (r(s) = 0.324, P = 0.001; r(s) = 0.267, P = 0.006, respectively), vessel invasion (r(s) = 0.579, P = 0.001; r(s) = 0.209, P = 0.032, respectively), lymph node metastasis (r(s) = 0.405, P = 0.001; r(s) = 0.343, P = 0.001, respectively) and distant metastasis (r(s) = 0.474, P = 0.001; r(s) = 0.468, P = 0.001, respectively), but not correlated to tumor type (r(s) = 0.134, P = 0.173; r(s) = 0.103, P = 0.145, respectively) and differentiation (r(s) = 0.096, P = 0.332; r(s) = 0.102, P = 0.298, respectively); And then, the mean MVD in tumors with infiltrating type, stage T(3)-T(4), vessel invasion, lymph node metastasis and distant metastasis was significantly higher than that in tumors with expanding type (t = 10.105, P = 0.001), stage T(1)-T(2) (t = 5.961, P = 0.001), non-vessel invasion (t = 7.394, P = 0.001), non-lymph node metastasis (t = 3.819, P = 0.01) and non-distant metastasis (r = 10.578, P = 0.001); There was a positive relationship between MVD and bFGF mRNA and MMP-9 mRNA (t = 3.207, P = 0.002; t = 7.035, P = 0.001), respectively; the mean survival time in cases with positive bFGF mRNA and MMP-9 mRNA and MVD value >/= 39.5 was significantly shorter than that in cases with their negative expression and MVD value < 39.5. CONCLUSIONS: bFGF and MMP-9 promote angiogenesis in gastric cancer. Test of the expression of bFGF and MMP-9 may act as an useful index to determine angiogenesis, invasion, metastasis and patients survival.

Adult↗
PubMed1981

Extensive homology between poly(A)-containing mRNA and purified nominal poly(A)-lacking mRNA in mouse kidney.

To investigate poly(A)-lacking mRNA in mouse kidney, we studied a fraction of renal mRNA that does not bind to oligo(dT)-cellulose but can be purified by benzoylated cellulose chromatography. Nominal poly(A)-lacking mRNA and poly(A)-containing mRNA have complete nucleotide sequence homology, suggesting that kidney does not contain mRNAs that are not represented in the polyadenylated RNA fraction. Translation products directed by nominal poly(A)-lacking mRNA and poly(A)-containing mRNA are qualitatively and quantitatively similar in one-dimensional polyacrylamide gels. [3H]cDNA transcribed from poly(A)-containing mRNA hybridizes with its template and with nominal poly(A)-lacking mRNA to the same extent (95%) and with the same kinetics; reaction of [3H]cDNA to nominal poly(A)-lacking mRNA with the two mRNA populations gives the same result. The extensive homology these two mRNA populations share is important to the interpretation of mRNA lifetime and to the analysis of authentic poly(A)-lacking mRNAs.

Animals↗
PubMed1995

Cycloheximide induces nitric oxide synthase mRNA in vascular smooth muscle cells by prolonging mRNA lifetime.

Bacterial lipopolysaccharide (LPS) and other immunostimulants induce an isoform of NO synthase (iNOS) in vascular smooth muscle (VSM) which produces large quantities of NO and profound vasodilation; this process has been implicated as the cause of gram-negative septic shock. Although regulation of iNOS has been considered to occur at the level of transcription, it is unclear whether post-transcriptional events also contribute to changes in iNOS mRNA expression. We show that cycloheximide (CH), an inhibitor of protein synthesis, induces iNOS mRNA in VSM and potentiates the induction of iNOS mRNA caused by LPS. For many early-response genes, protein-synthesis inhibitors enhance mRNA levels by increasing mRNA stability. Since iNOS mRNA contains multiple copies of a consensus sequence (AUUUA) in common with these eary-response genes and responsible for mRNA destabilization, we tested whether CH induces iNOS mRNA by prolonging mRNA lifetime. In the absence of CH, iNOS mRNA decayed with biphagic kinetics and a half-life of 2 h. In the presence of CH, half-life was prolonged to approximately 7 h. Our observations indicate that in VSM the stability of iNOS mRNA may be under the control of a labile protein factor which awaits identification and characterization. Regulation of mRNA lifetime represents a novel site for control of iNOS gene expression.

Animals↗