Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “total RNA”

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 361 records · Page 20Linked to original sources
PubMed1984

Identification of messenger RNA for human type II collagen.

Total RNA was purified from human fetal calvaria and articular cartilage. Messenger RNAs for type I and II collagens were identified by hybridization using cDNA clones for chicken pro alpha 1(I)-, pro alpha 2(I)- and pro alpha 1(II)collagen mRNAs and by analysis of cell-free translation products of these RNAs by polyacrylamide gel electrophoresis. The size of human pro alpha 1(II)collagen mRNA is approx. 5100 bases. Translatability of cartilage specific type II collagen mRNA was found to be concentration dependent: with increasing total RNA concentrations the relative translation of type II collagen mRNA was reduced with respect to type I mRNAs.

Animals↗
PubMed2000

[Is Na+Ca(2+) exchanger expression altered in the endomyocardium of patients with chronic heart valve diseases parallel to myocardial dysfunction?].

BACKGROUND: Na(+)-Ca2+ exchanger (EXCH) is an important regulator of intracellular calcium homeostasis. To maintain a normal intracellular Ca2+ concentration, EXCH expression may be upregulated before the onset of end-stage heart failure. We tested for a correlation between the EXCH transcription level and the degree of myocardial dysfunction as well as the suitability of EXCH transcription as a molecular marker for early detection of a transition from adequate to inadequate myocardial adaptation to chronic pressure and/or volume overload in valvular heart disease (VHD). METHODS: The level of EXCH transcription was analyzed in myocardial biopsies from eleven patients with aortic stenosis (AS), five with aortic regurgitation (AR) and six with primary mitral regurgitation (MR) of different hemodynamic severity and myocardial impairment using the quantitative rt-PCR technique. In addition, endomyocardial tissue from thirteen explanted hearts with end-stage heart failure and biopsies from seven individuals without heart disease were investigated. RESULTS: The mean level of EXCH transcription in patients with AS was: 1.8 +/- 1.4 amol/ng total RNA, with AR: 1.9 +/- 0.8 amol/ng and with MR: 2.2 +/- +2.1 amol/ng. This was not from different controls (2.6 +/- 1.2 amol/ng total RNA). However, in myocardium from end-stage heart failure, EXCH transcription was increased fourfold amounting to 8.9 +/- 1.9 amol/ng total RNA. No difference in the EXCH transcription was found in VHD with respect to the degree of myocardial dysfunction: cardiac index (CI) > 3.5 l/min/m2 (EXCH 1.4 +/- 1.1 amol/ng total RNA); CI 3.5-2.4 (EXCH 2.5 +/- 1.8); CI < 2.4 (EXCH 1.8 +/- 1.0); EF-angio > 50% (EXCH 1.9 +/- 1.8); EF-angio < or = 50% (EXCH 1.9 +/- 0.9); EF-RNV > 50% (EXCH 2.4 +/- 1.8), EF-RNV < or = 50% (EXCH 1.7 +/- 1.0). CONCLUSION: Myocardial EXCH transcription does not change parallel to the degree of myocardial dysfunction in VHD. Consequently, myocardial EXCH transcription does not appear to be suitable as a parameter indicating the transition from adequate to inadequate myocardial adaptation to chronic volume and/or pressure overload.

Adaptation, Physiological↗
PubMed1991

Qualitative changes of total cytoplasmic RNA size patterns in estrogen-induced adenoma in female rats.

Estradiol was administered 2.5 mg once a week for 4, 8 and 16 weeks to female Wistar rats. Hyperprolactinemia corresponding to the size of the pituitary developed along the pituitary enlargement after 4 weeks and macroscopically apparent pituitary adenomas after 8 and 16 weeks of treatment. The total pituitary cytoplasmic RNA was isolated from treated and control animals and the size distribution pattern of total RNA was obtained by sucrose gradient centrifugation. Estrogen treatment did not change that pattern in the first 4 weeks of treatment, but considerable RNA size distribution changes mainly in the medium size molecular range occurred after 8 and 16 weeks of estrogen administration. It can be hypothesized that an effect of estrogens on pituitary lactotroph hypersecretion and proliferation is not identical with events of irreversible adenomatous cell transformation which occurs later on during chronic estrogen administration.

Animals↗
PubMed1996

Distribution of cAMP-activated chloride current and CFTR mRNA in the guinea pig heart.

Guinea pig ventricular myocytes exhibit a Cl(-)-selective current regulated by the cAMP-dependent pathway. We have investigated the distribution of cAMP-activated Cl- channel current density and cystic fibrosis transmembrane-conductance regulator (CFTR) mRNA in three regions of the guinea pig heart: the atrium, and the epicardium and endocardium of the free wall of the left ventricle. The regional differences in the Cl- current density were investigated in enzymatically isolated myocytes using the whole-cell patch-clamp technique. Forskolin (1 mumol/L) activated Cl(-)-selective currents in all ventricular myocytes and 21% of atrial myocytes examined. The conductance density, estimated as the outward chord conductance normalized to cell capacitance, was greatest in epicardial myocytes (79.8 +/- 8.4 pS/pF, n = 21) and significantly lower in endocardial (59.8 +/- 9.5 pS/pF, n = 22) and atrial (10.9 +/- 5.0 pS/pF, n = 38) myocytes. The regional differences in CFTR mRNA expression levels were investigated by competitive reverse-transcribed polymerase chain reaction. The regional distribution of the mRNA levels was similar to that of the Cl- conductance density, ie, highest in the epicardium (23230 +/- 1840 molecules/microgram total RNA, n = 3), significantly lower in endocardium (10610 +/- 780 molecules/microgram total RNA, n = 3), and lowest in atrium (1450 +/- 290 molecules/microgram total RNA, n = 3). The data indicate that regional differences in CFTR mRNA expression in the guinea pig heart are responsible, at least in part, for the regional differences in cAMP-activated Cl- current density.

Animals↗
PubMed2005

Effects of varied EGCG and (+)-catechin concentrations on proinflammatory cytokines mrna expression in cona-stimulated primary white blood cell cultures.

EGCG [(-)-epigallocatechin gallate] and (+)-catechin hydrate are flavanoids, which are known as anticancer and healthy drugs. To test the immune modulatory effects of EGCG and catechin, various concentrations were tested on primary white blood cells (WBC) in cell cultures stimulated with the T-cell mitogen concanavalin A (ConA). WBC from dairy cows (1 x 10(6) cells/mL) were cultivated using RPMI medium with FCS and gentamycin. First, WBC were stimulated with ConA, and 6 h later the flavanoid treatment was started. Cultivated WBC were treated with various physiological flavanol concentrations (0-100 microM) in cross-combination with various ConA concentrations (0-1 microg/mL). After 24 h, cells were harvested, cell viability was verified, and total RNA was isolated. Relative mRNA expression levels of proinflammatory cytokines TNFalpha, IL1beta, IL6, and transcription factor cFos and of nucleosome component histon H3 were quantified with real-time qRT-PCR. High EGCG and catechin concentrations had inhibitory effects on total RNA expression. Low EGCG concentration can induce total RNA expression in WBC. EGCG reduced cFos mRNA expression, which can be abolished by high ConA concentrations in a reverse dose-dependent manner. TNFalpha showed a flavanoid-specific expression pattern. EGCG acts in blood physiological concentrations (micromolar range), and catechin acts in higher gut-relevant concentrations (millimolar range) and has the potential to influence the proinflammatory TNFalpha expression. Higher flavanoid concentration had more pronounced effects than lower, whereas EGCG showed a more potent suppression of gene expression than catechin (toward TNFalpha). EGCG and catechin had no significant effects in primary WBC on the expression pattern of the proinflammatory cytokines IL1beta and IL6 and on the expression of the housekeeping genes GAPDH and histon H3. It is presumed that both flavanoids have the potential to regulate total RNA expression and gene-specific expression in WBC.

Animals↗
PubMed1994

Hormonal regulation of some steps of thyroglobulin synthesis and secretion in bicameral cell culture.

Porcine thyroid cells were cultured for 15 days on porous bottom chambers with or without different mixtures of hormones added to serum-free basal medium. Assays with 10% serum were also performed for comparison with previously published results. The effects of the hormones, particularly insulin, TSH and hydrocortisone, were studied on total RNA content, thyroglobulin mRNA level, the amount of thyroglobulin secreted into the apical medium and on glycosylation. Insulin and TSH similarly increased the total RNA content, and their effects were additive. Thyroglobulin mRNA content was increased twofold by insulin and threefold by TSH. When they were added simultaneously, the maximal level of thyroglobulin mRNA was reached, showing that TSH and insulin effects on thyroglobulin gene expression were additive. Hydrocortisone alone did not modify total RNA or thyroglobulin mRNA content but the hormone amplified total RNA when insulin and TSH were present together. The basal level of thyroglobulin secreted into the apical medium was increased threefold by insulin and fourfold by TSH. The effects of these two hormones added together appeared to be additive. Hydrocortisone had no effect alone or even when combined with insulin or TSH. However, when the three hormones were added together, the hormonal response was amplified. TSH effect and insulin effect on the incorporation of 3H-mannose into thyroglobulin as well as on the anionic residue content of the molecule were additive.

Animals↗
PubMed1995

Analysis of transfer RNA during the early embryogenesis of the freshwater teleost, Heteropneustes fossilis.

Total RNA as well as transfer RNA were quantified from mature ova apart from four different embryonic stages namely mid-cleavage, early gastrula, mid-gastrula and organogenesis of the freshwater teleost Heteropneustes fossilis. Total RNA as well as transfer RNA quantity follow a similar variation pattern, being maximum during mid-gastrulation. When analysed by total amino acid acceptance capacity, transfer RNA shows its maximum activity during mid-gastrulation. This coincides with the higher ratio of tRNA to total RNA at this stage. The relative aminoacylation capacity for Ser, Gly, Asn and Thr are found to be higher (9-34%) compared to that for other amino acids. Total tRNA, resolved into three peaks upon HPLC fractionation, shows a high cumulative peak area during mid-gastrulation and organogenesis. These results indicate a switch over of maternal to embryonic translation machinery during gastrulation.

Animals↗
PubMed2000

Changes in diabetic retinal matrix protein mRNA levels in a common transgenic mouse strain.

Recently, all the structural features of non-proliferative diabetic retinopathy have been demonstrated in mice fed 30% galactose for 21-26 months. To determine whether changes in retinal matrix protein mRNA levels occur early in the course of murine diabetes we used a competitive RT-PCR method to quantitate retinal mRNA levels in an inbred mouse strain (FVB) commonly used for transgenic studies. Retinal mRNA was prepared from STZ-diabetic and non-diabetic FVB mice at 4, 8, 12 and 16 weeks and cDNA encoding basement membrane components was quantitated using MIMIC constructs that compete for the same primer pairs. alpha1 (IV) collagen, the beta1 and gamma1 chains of laminin, fibronectin, and vitronectin mRNAs were quantitated. For alpha1 (IV) collagen, statistically significant diabetes-induced increases were apparent by 8 weeks (3.11 +/- 0.20 vs. 1.29 +/- 0.19 x 10(6) molecules/mg total RNA, p < 0.005). Similarly, diabetes-induced increases were observed by 8 weeks for the beta1 chain of laminin (4.54 +/- 0.22 vs. 1.85 +/- 0.43 x 10(5) molecules/mg total RNA, p < 0.005), the gamma1 chain of laminin (7. 33 +/- 0.29 vs. 4.84 +/- 0.76 x 10(4)/microg total RNA, p < 0.05), and for fibronectin (2.22 +/- 0.21 vs. 1.35 +/- 0.15 x 10(6) molecules/mg total RNA, p < 0.05). The magnitude of change was greatest for alpha1 (IV) collagen (2.4-fold) and beta1 laminin (2. 5-fold) at 8 weeks, and least for fibronectin (1.6-fold). A smaller diabetes-induced increase in vitro nectin mRNA was also observed, but it failed to reach statistical significance at 12 and 16 weeks. These data provide the basis for assessing the effects of genetic manipulation on diabetic retinopathy in transgenic mouse models.

Animals↗
PubMedDate not supplied

[Effect of external irradiation with different intensity at 1 Gy dose on the DNA, RNA and total protein content in the testis and liver of rats].

The content of DNA, RNA and total protein in the rat testes and liver was studied 1 and 30 days after external chronic gamma-irradiation (dose rate 1.8 and 5.76 cGy/day) and acute gamma-irradiation with relatively low dose rate (5.4 cGy/min) up to a total dose of 1 Gy. The results obtained pointed to the specific metabolic reaction of radiosensitive (testes) and radioresistant (liver) tissues of organism at external irradiation at relatively low dose of different intensity due to unequal cell capacity for proliferation.

Animals↗
PubMed1999

The renal endothelin system in the Prague hypertensive rat, a new model of spontaneous hypertension.

In a new model of spontaneous hypertension, namely the Prague hypertensive rat (PHR), hypertension is transferred with a kidney transplanted from the PHR to its normotensive counterpart (PNR) by an as yet unknown mechanism. One candidate may be endothelin (ET), since this potent vasoconstrictor affects vascular tone, renal haemodynamics and renal excretory function, and all members of this peptide family are located within the kidney and act in an autocrine/paracrine fashion. In the present study we investigated, in the renal tissue of PHRs and PNRs: (1) preproET-1 and preproET-3 mRNAs as well as ET-1 and ET-3 peptide distribution, (2) endothelin-converting enzyme (ECE)-1 mRNA expression, and (3) ET receptors and their characteristics in membranes of glomeruli and papillae. In addition, plasma ET concentration and urinary ET excretion were determined. Quantitative measurements by competitive reverse transcription-polymerase chain reaction revealed ET-1 mRNA levels in the renal cortex from PHRs and PNRs of 1.09+/-0.13 and 1. 29+/-0.18 amol/microgram of total RNA respectively, and in red medulla of 2.72+/-0.82 and 3.30+/-0.68 amol/microgram respectively. In contrast, renal papilla from PHRs showed significantly lower levels of preproET-1 mRNA (1.81+/-0.64 amol/microgram of total RNA, compared with 4.25+/-0.82 amol/microgram in PNRs; each n=5; P<0.05). The ET-1 peptide concentration in papillary tissue was also significantly lower in PHRs than in PNRs (120.2+/-30.8 and 491.3+/-53.4 fmol/mg of protein respectively; n=5; P<0.01), whereas it was similar in cortex and medulla from PHRs and PNRs. The preproET-3 mRNA content in renal tissue was much lower than that of preproET-1 mRNA. It was significantly higher in red medulla from PHRs compared with that from PNRs (0.25+/-0.05 and 0.13+/-0.02 amol/microgram of total RNA respectively; P<0.05), but was similar in papillae of PHRs and PNRs (0.04+/-0.02 and 0.05+/-0.01 amol/microgram respectively; n=5). Cortical preproET-3 mRNA was at the lower limit of detection. Similarly, the ET-3 peptide concentration was slightly but significantly higher in the red medulla of PHRs compared with PNRs (15.4+/-2.0 and 8.8+/-0.8 fmol/mg of protein respectively; n=5; P<0. 05), whereas no differences in ET-3 peptide concentration were found in papillae from PHRs and PNRs. ECE-1 mRNA levels were similar in the renal cortex, red medulla and papillae from PHRs and PNRs, ranging between 0.34+/-0.03 and 0.56+/-0.12 amol/microgram of total RNA. Of the total ET receptors in glomerular membranes, 39% were ETA receptors, whereas papillary membranes contained exclusively ETB receptors. PHRs and PNRs showed similar Bmax and Kd values for ET-1 in renal glomerular membranes (Bmax, 6.5+/-1.3 and 4.9+/-1.2 pmol/mg of protein respectively; Kd, 0.69+/-0.10 and 0.56+/-0.10 nM respectively) and papillary membranes (Bmax, 9.7+/-1.1 and 11.3+/-1. 6 pmol/mg of protein respectively; Kd, 0.30+/-0.04 and 0.42+/-0.07 nM respectively). Plasma ET-1/2 concentrations (10.4+/-1.3 and 12. 2+/-1.2 fmol/ml in PHRs and PNRs respectively) and urinary ET-1 excretion (3.1+/-0.3 and 3.0+/-0.2 pmol/24 h in PHRs and PNRs respectively) were similar in hypertensive and normotensive rats. In summary, although tissue levels of preproET-3 mRNA were very low in the kidney, significantly greater amounts of preproET-3 mRNA and ET-3 peptide were found in medullary tissue from PHRs compared with PNRs, a finding that awaits further investigation. In contrast, the preproET-1 mRNA content and ET-1 peptide concentration were significantly lower in papillary tissue from PHRs compared with PNRs. Decreased synthesis of ET-1, which normally antagonizes the action of [Arg8]vasopressin, may allow increased water (and sodium) reabsorption at the level of the inner medullary collecting duct. This intrinsic defect of the kidney in the PHR may contribute to hypertension in this model, and may transmit high blood pressure on transplantation of the 'hypertensive' kidney i

Actins↗
PubMed2002

Degradation profile of mRNA in a dead rat body: basic semi-quantification study.

To profile postmortem degradation of mRNA, total RNA was extracted, at given postmortem intervals, from the brain, lung, heart and liver of rats left at 20 degrees C. In electrophoretic analysis, total RNA was most stable in the brain, moderately stable in the lung and heart, and most unstable in the liver. Northern blot analysis of total RNA extracts from the brain and liver of dead rats with a cDNA probe for glyceraldehyde-3-phosphate dehydrogenase (GAPDH) showed that GAPDH mRNA degraded in a similar fashion to total RNA. Analysis of the postmortem degradation profile of GAPDH mRNA with real-time reverse transcriptase-polymerase chain reaction (real-time RT-PCR) gave results consistent with those above, indicating that real-time RT-PCR is reliable for estimation of the mRNA level in specimens from dead bodies. Real-time RT-PCR analysis showed that degradation rates of three housekeeping genes, GAPDH, beta-actin and hypoxanthine guanine phosphoribosyltransferase, in the brains of dead rats were similar. The degradation rate of interleukin-1beta (IL-1beta) mRNA induced by intravenous injection of LPS to rats was higher than that of GAPDH mRNA in the lung. In real-time RT-PCR analysis using GAPDH mRNA as an internal standard, the detection level of IL-1beta mRNA decreased in the postmortem interval. However, enhanced expression of IL-1beta was detected for at least 3 days postmortem.

Actins↗
PubMed2004

Establishment of a real-time RT-PCR for the determination of absolute amounts of IGF-I and IGF-II gene expression in liver and extrahepatic sites of the tilapia.

We developed a one-tube two-temperature real-time RT-PCR that allows to absolutely quantify the gene expression of hormones using the standard curve method. As our research focuses on the expression of the insulin-like growth factors (IGFs) in bony fish, we established the technique for IGF-I and IGF-II using the tilapia (Oreochromis niloticus) as model species. As approach, we used primer extension adding a T7 phage polymerase promoter (21 nt) to the 5' end of the antisense primers. This procedure avoids the disadvantages arising from plasmids. Total RNA extracted from liver was subjected to conventional RT-PCR to create templates for in vitro transcription of IGF-I and IGF-II cRNA. Correct template sizes including the T7 promoter were verified (IGF-I: 91 nt; IGF-II: 94 nt). The PCR products were used to create IGF-I and IGF-II cRNAs which were quantified in dot blot by comparison with defined amounts of standardised kanamycin mRNA. Standardised threshold cycle (Ct) values for IGF-I and IGF-II mRNA were achieved by real-time RT-PCR and used to create standard curves. To allow sample normalisation the standard curve was also established for beta-actin as internal calibrator (template: 86 nt), and validation experiments were performed demonstrating similar amplification efficiencies for target and reference genes. Based on the standard curves, the absolute amounts of IGF-I and IGF-II mRNA were determined for liver (IGF-I: 8.90+/-1.90 pg/microg total RNA, IGF-II: 3.59+/-0.98 pg/microg total RNA) and extrahepatic sites, such as heart, kidney, intestine, spleen, gills, gonad, and brain considering the different lengths of cRNAs and mRNAs by correction factors. The reliability of the method was confirmed in additional experiments. The amplification of descending dilutions of cRNA and total liver RNA resulted in parallel slopes of the amplification curves. Furthermore, amplification plots of the standard cRNA and the IGF-I and IGF-II mRNAs showed signals starting at the expected Ct values. Thus, the one-tube RT-PCR described here is highly sensitive (detection level approximately 2 pg/microg total RNA) and allows precise absolute quantification. The method is rapid as there are neither separate reverse transcriptions nor post-amplification steps, and can be executed with low risk of contamination. Therefore, it will be helpful when investigating gene expression in any species and tissue whenever absolute levels are of concern.

Animals↗
PubMed1986

Transcriptional-translational regulation of muscle-specific protein synthesis and its relationship to chondrogenic stimuli.

Demineralized bone (bone matrix) has a well-characterized ability to evoke the re-differentiation of cells derived from skeletal muscle into chondrocytes. Recent investigations in this laboratory have shown that muscle-specific (alpha) actin synthesis continues throughout redifferentiation. Conversely, expression of the cartilage phenotype is associated with repression of muscle-specific enzyme synthesis. The present experiments were undertaken to determine the mode of genomic regulation responsible for control of these muscle-specific syntheses. As part of these experiments, we investigated the ability of embryonic and adult RNA to direct translation in vitro. The results indicate that unfractionated (total) RNA is capable of directing the efficient synthesis of actin, but not myosin heavy or light chains. Decreased abundance of polyadenylated mRNA cannot account for lack of myosin synthesis. Polyadenylated mRNA, however, directed synthesis of actin and myosin with an efficiency greater than that of total RNA. This data suggested that embryonic total RNA was subject to translational control. Dot blot hybridization against cDNA probes for alpha-actin, myosin heavy chain, and fast light chains demonstrated that myogenic cells were subject to a pattern of mixed transcriptional and translational control. It is hypothesized that full expression of the muscle phenotype involves sequential release of transcriptional, and subsequently, the translational controls. We have also observed that cultures of skeletal muscle on bone matrix contain mRNA for muscle-specific proteins, even through the period normally characterized by chondrogenesis. In the absence of concurrent enzyme protein synthesis, it appears that one action of bone matrix is to continue genomic controls that in the source skeletal muscle maintain the genome in an embryonic (translationally repressed) state.

Animals↗
PubMed2005

Detection and epidemiological characteristics of peach latent mosaic viroid in Tunisia.

A rapid and sensitive assay was developed for the detection and identification of Peach latent mosaic viroid (PLMVd) by reverse transcription-polymerase chain reaction (RT-PCR) in infected tissues from Tunisian orchards. The test was initially performed by using total RNA preparations from selected isolates and then applied on total RNA preparations from leaf or bark tissues of fruit trees collected in 2003 in 20 orchards in the North of Tunisia and the Sahel. PLMVd occurred in peach and pear trees. The identity of the detected viroid was confirmed by comparison of its sequence with other isolates previously characterized. The test was then simplified by direct use of diluted crude plant extracts. The results obtained from crude sap extracts of leaves or bark tissues are identical to those obtained from total RNA preparations. Epidemiological characteristics of PLMVd on peach trees have been investigated. A survey of peach trees was carried out in 32 orchards in May 2004. The obtained results showed that (1) PLMVd is highly and equally present in several regions of the north of Tunisia rather than the central, the Sahel and the southern regions, (2) infection percentage increases with the age of the tree and (3) the studied cultivars are classified into three groups of sensitivity.

Gene Amplification↗
PubMed1968

Studies on the ribonucleic acids of fresh and processed tea leaves.

1. A marked decrease in the total RNA content during the withering process of tea leaves was found. During the fermentation process, there was a small but significant decrease in the total RNA content. 2. During isolation of RNA from tea leaf tissues, the action of leaf ribonuclease was minimized by the addition of sodium dodecyl sulphate during extraction; 1% (w/v) sodium dodecyl sulphate in 0.2m-tris-hydrochloric acid buffer, pH8.0, containing 0.005% EDTA was found to be most efficient for the extraction and gave about 93% yield. 3. The total RNA preparations isolated from fresh, withered and fermented tea leaves were compared with regard to nucleotide composition and spectral characteristics. The total RNA preparations from all three sources contained more purines than pyrimidines (purine/pyrimidine ratio 1.47-1.52).

Chromatography, Paper↗
PubMed1980

Double-stranded sequences in RNA of Drosophila melanogaster: relation to mobile dispersed genes.

Double-stranded RNA (dsRNA) sequences were isolated from either total RNA or cytoplasmic poly(A)+RNA of D. melanogaster culture cells using a method described previously /1,2/. Virtually all dsRNA was found to be of high molecular weight (> 200 base pairs) and unable to snap back after RNA melting. Thus, it corresponds to one of dsRNA classes found in mouse cells, namely, to dsRNA-A /3/. Three different cloned DNA fragments of D melanogaster which hybridized to melted dsRNa were selected among 100 randomly taken. All of them efficiently bound poly(A)+RNA and high percentage of total cellular DNA. According to these and other properties, they were assigned to a group of mobile dispersed genes of D. melanogaster. DsRNA hybridizes to all subfragments of the two mobile dispersed genes tested (mdg 1 and mdg 3). Thus, complete transcripts of mobile dispersed genes are present in dsRNA. In total RNA, transcripts from one strand are more abundant than those from another one. DsRNA is heavily enriched in the transcripts from mobile dispersed genes as compared to total or poly(A)+RNA of the cytoplasm. It has been suggested that dsRNA in D. melanogaster is formed as the result of symmetric transcription of mobile dispersed genes. At least in the cytoplasmic fraction, two complementary strands are separated in vivo and may combine during the isolation of RNA.

Chromatography, Gel↗
PubMed2004

Differential expression of the nitrite reductase gene family in tobacco as revealed by quantitative competitive RT-PCR.

Tobacco (Nicotiana tabacum L. cv. Xanthi XHFD8) possesses four nitrite reductase (NiR) genes: nii1, nii2, nii3, and nii4. Their differential expression in leaves and roots was investigated by quantitative competitive RT-PCR using gene-specific primer pairs. These results appear to contradict existing views on the expression of these NiR genes: (i) the mRNA of each of the four NiR genes was distinguishable both in leaves and roots; (ii) nitrate treatment increased nii1 and nii3 mRNA in leaves and roots by at least 4-fold (at least 5-fold in nii2 and nii4 mRNA); and (iii) the steady-state levels of nii1 and nii3 mRNA were almost the same in leaves (6-7 x 10(5) and about 3 x 10(6) copies microg(-1) of total RNA before and after nitrate treatment, respectively) and in roots (3-4 x 10(4) and 3-6 x 10(5) copies microg(-1) of total RNA before and after nitrate treatment, respectively). Very similar relationships were obtained for the steady-state levels of nii2 and nii4 mRNA in roots (2-4 x 10(5) and 8 x 10(6) copies microg(-1) of total RNA before and after nitrate treatment, respectively), and in leaves (5-9 x 10(4) and 4 x 10(5) copies microg(-1) of total RNA before and after nitrate treatment, respectively). These results demonstrate that nii1 and nii3 transcripts are a dominating, but not exclusive, NiR mRNA in leaves, and the same is true for nii2 and nii4 transcripts in roots.

Gene Expression Regulation, Plant↗