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At least 739 records · Page 41Linked to original sources
PubMed1978

Effects of alpha-amanitin on RNA synthesis by mouse embryos in culture.

Investigations were conducted to test the effects of alpha-amanitin on RNA synthesis in preimplantation mouse embryos. Exposure of embryos in culture to 1-100 microgram/ml alpha-amanitin produced a dose- and time-dependence suppression of total RNA synthesis as measured by incorporation of [3H]uridine. Synthesis of polyadenylated RNA in blastocyst-stage embryos was abolished by alpha-amanitin-treatment at concentrations and exposure times that suppressed total RNA synthesis by less than 15%. DNA-dependent RNA polymerase activity was measured in lysates of embryos at several stages of preimplantation development. alpha-Amanitin suppressed total polymerase activity assayed under ionic conditions favorable to the detection of RNA polymerase II. Electrophoretic analyses revealed that preincubation of blastocysts in 100 microgram/ml alpha-amanitin reduced labelling of cytoplasmic 28S and 18S RNA by inhibition of both synthesis and maturation of nucleolar 45SrRNA-precursor. This action of alpha-amanitin on nucleolar RNA synthesis cannot be correlated with the minimal suppression of nucleolar RNA polymerase activity and suggests that the synthesis and processing of rRNA may be under control of nucleoplasmic gene products.

Amanitins↗
PubMed2003

Rapid extraction of RNA and analysis of transcript levels in Chlamydomonas reinhardtii using real-time RT-PCR: Magnesium chelatase chlH, chlD and chlI gene expression.

The reverse transcriptase polymerase chain reaction (RT-PCR) is an extremely sensitive technique for detecting RNA transcripts. Real-time RT-PCR using fluorescent dyes and instruments such as the Roche Lightcycler allows real-time kinetic quantification of transcript levels. Here we report a method for the relative quantification of RNA transcripts using real-time RT-PCR that gives results comparable to Northern blotting utilizing 10-100 fold less RNA. We have also optimized a method for the rapid and efficient extraction of RNA from Chlamydomonas reinhardtii. The method is more rapid than other methods tested, allows simultaneous processing of multiple samples, and yields reproducible quantities of total RNA from a fixed number of cells. In addition the purified total RNA is of high quality and polyA-mRNA can be easily isolated. Using these methods we found that the pattern of changes in RNA transcript levels of the magnesium chelatase (Mg-chelatase) genes, chlH, chlD and chlI, of C. reinhardtii grown under synchronous culture conditions in light/dark cycles are similar and that light is involved in this regulation.

Journal Article↗
PubMed2005

[Identification of stage Ib specific related genes in lung squamous cell cancer by oligonucleotide array].

OBJECTIVE: To establish gene expression profile of stage Ib and IIIa primary lung squamous cell cancer (SCC) within whole genome and identify genes specifically expressed in stage Ib of SCC. METHODS: Total RNA was extracted from the normal, stage Ib and IIIa lung SCC tissue. cRNA probes prepared from total RNA were hybridized with pretreatment oligonucleotide chip containing 22215 genes. The resultant data were treated with MSV 5.0 software and looked up on the affymetrix website. RT-PCR examination were used to validated the results from chip analysis. RESULTS: Comparing with the normal lung, difference genes expressed in Ib SCC are totally 1764, among which 571 were upregulated and 1193 were downregulated, and in stage IIIa, they are 554, 128 and 426 genes respectively. Genes specifically expressed in stage Ib were totally 1329, including 482 upregulation genes and 847 downregulation genes, which were classified into different category which included 480 metabolism related genes, 227 signal transduction genes, 136 cell proliferation genes, 136 immune related genes, 94 cell adhere genes, 88 transcription regulation genes, 86 cell cycle genes, 73 cytoskeleton genes, 45 differentiation genes, 42 apoptosis and 31 extracellular matrix genes. RT-PCR examination of FOXM1 and TNXB genes was consistent with the analysis of gene chip. CONCLUSION: Stage Ib and IIIa Gene expression profile of primary SCC within the whole genome were set up and genes specifically expressed in stage Ib of SCC were identified, which lay a foundation for further research on carcinogenesis mechanism and identifying new markers of early diagnosis.

Carcinoma, Squamous Cell↗
PubMed1989

Heavy metal ion-induced changes of ribosomal RNA synthesis in Synechococcus sp. strain PCC 6301, a cyanobacterium.

We examined the effect of cadmium, zinc, copper and mercury ions on the rate of total RNA synthesis and on the accumulation of ribosomal RNAs in Synechococcus sp. PCC 6301, an obligate photoautotrophic cyanobacterium. It was found that treatment of cells with growth-inhibitory concentrations of cadmium and zinc ions severely decreased the rate of total RNA synthesis both under light (growing) and dark (non-growing) conditions, while copper and mercury ions had different inhibitory effects under these conditions. Moreover, cadmium and zinc ions substantially inhibited the "normal" processing of high-molecular-mass rRNAs and the in vivo postmaturational cleavage of 23S rRNA in the light and interfered with the accumulation of dark-specific RNAs of 0.33 x 10(6), 0.24 x 10(6) and 0.16 x 10(6) daltons in the dark. On the other hand, copper and mercury ions had a similar effect in the light, but did not abolish the accumulation of dark-specific, rRNA-derived, RNAs in the dark.

Cadmium↗
PubMed1991

Estrogenic regulation and sex dimorphism of growth-associated protein 43 kDa (GAP-43) messenger RNA in the rat.

In addition to effects on brain protein synthesis, neurotransmitter release, and electrophysiology, estrogens alter neurite outgrowth and synaptogenesis. This study examined in the adult rat the effects of estrogen and sex on the expression of the GAP-43 gene; encoding a phosphoprotein structurally and physiologically linked to these two processes in the rat CNS. Ovariectomized (OVX) rats were injected with vehicle or estrogen, or male and female rats were either gonadectomized or left intact. Brains were dissected to obtain ventromedial hypothalamus (VMH), posterior hypothalamus (PH), or frontal cortex (CTX). Total RNA from these areas were extracted, and slot-blots of equal masses of total RNA were hybridized to 32P-labeled cDNAs for GAP-43 and beta-actin, and also to synthetic poly-dT. Resultant autoradiograms were scanned by laser densitometry, quantitated, and ratios of the gray scale generated by each probe were compared between experimental groups. GAP-43 mRNA expression, when compared to expression of either beta-actin mRNA or total poly(A)-containing RNA (poly(A) RNA), was higher in VMH and PH as compared to CTX. Estrogen treatment of OVX rats resulted in a 48-74% increase in GAP-43 mRNA levels in the VMH--in one experiment, this increase was noted after 2 h of estradiol treatment, and in another after 3 days of estradiol benzoate treatment; but PH and CTX were unaffected by either estrogen regimen. Conversely, ovariectomy of intact rats decreased GAP-43 mRNA expression by 45% in the VMH, but not in the CTX.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2000

Fetal lung development: airway pressure enhances the expression of developmental genes.

BACKGROUND/PURPOSE: The mechanisms by which static airway pressures in the developing lung affect development are unknown. The in vitro murine fetal lung model with airway ligation reproduces the phenomenon of intraluminal airway pressure in developing lungs. We have applied the technique of differential display of mRNAs to fetal murine lungs that were maintained in organ culture with and without tracheal ligation. The goal of this investigation was to identify genes that are induced or enhanced by airway pressure during lung development. METHODS: Fetuses were harvested from CD-1 mice on gestational day (Gd) 14. The lungs were removed and trachea either transected or ligated and organ cultured for 7 days. Total RNA was extracted from cultured unligated controls and ligated lungs. Reverse transcription (RT) of the purified total RNA from each pooled sample was performed with anchor primer H-T11G or C and one of 24 arbitrary primers followed by polymerase chain reaction (PCR) of the RT mixtures. PCR products were electrophoresed on a DNA sequencing gel. Differentially expressed cDNA bands of interest were cut from the dried gel. Each cDNA was then reamplified. Reamplified cDNAs were extracted, PCR amplified, cloned, and sequenced for homology to existing sequences in the GenBank database. RESULTS: Sequencing identified 4 differentially expressed genes enhanced by tracheal ligation: hepatoma-derived growth factor (HDGF), ribosomal protein S24, stathmin, and parathyroid hormone (PTH). CONCLUSIONS: Genes enhanced by airway pressure or tracheal ligation are mitogenic for fibroblasts, correlate with cell proliferation, regulate cell proliferation and differentiation, and may play a role in growth in distal lung and type II cell differentiation. Further work is necessary to identify the mechanisms by which these genes influence lung maturational processes.

Aniline Compounds↗
PubMed1997

Characterization and expression of a rice RAD23 gene.

In order to identify proteins that interact with plant transcriptional complexes, we performed a two-hybrid screen in yeast using a cDNA library from embryogenic rice suspension cultures and the plant transcriptional activator viviparous-1 (vp1) as 'bait'. In this screen, we detected an interaction between VP1 and a rice homologue of the Saccharomyces cerevisiae RAD23 gene (osRAD23). The RAD23 protein is associated with the general transcriptional machinery in yeast, and is believed to play a role in the processes of nucleotide excision repair in yeast and mammalian cells. This report is the first identification of a RAD23 homolog in plants. The osRAD23 amino acid sequence shares 50-60% similarity throughout its length with RAD23 sequences from yeast, mice, and man. osRAD23 contains a characteristic ubiquitin-like domain at its N-terminus, which is similar to other RAD23 genes. Analysis of the expressed sequence tag database identifies two different classes of RAD23 genes in both Arabidopsis and rice. Southern analysis of rice genomic DNA indicated the presence of at least two RAD23-like genes. A single transcript (1.5 kb) of osRAD23 was detected in total RNA from rice embryonic tissue, while three transcripts (1.8, 1.5 and 1.0 kb) were observed in total RNA from vegetative tissues of rice.

Amino Acid Sequence↗
PubMed1997

Keratinocyte growth factor mRNA expression in periodontal ligament fibroblasts.

Keratinocyte growth factor (KGF) is a fibroblast growth factor which mediates epithelial growth and differentiation. KGF is expressed in subepithelial fibroblasts, but generally not in fibroblasts of deep connective tissue, such as fascia and ligaments. Here we demonstrate that KGF mRNA is expressed in periodontal ligament fibroblasts, and that the expression is increased upon serum stimulation. Fibroblasts from human periodontal ligament, from buccal mucosa, from gingiva, and from skin were established from explants. Alkaline phosphatase activity was used as an indicator of the periodontal nature of fibroblasts. Cells were first cultured in DMEM with 0.5% fetal calf serum (FCS) and then incubated for 8 h, and 72 h in fresh DMEM with 10% FCS. Total RNA was isolated and used for Northern blotting with a P32-labeled KGF cDNA probe. Total RNA from cultured keratinocytes was used as negative controls. KGF mRNA was found in all cultured fibroblasts. Upon addition of 10% FCS to the cell cultures, an increase in KGF mRNA levels was noticed especially after 72 h. Furthermore, RT-PCR analysis of material scraped from the tooth root surface indicated the presence of KGF mRNA even in noncultured periodontal ligament cells.

Adolescent↗
PubMed2004

Automated purification and suspension array detection of 16S rRNA from soil and sediment extracts by using tunable surface microparticles.

Autonomous, field-deployable molecular detection systems require seamless integration of complex biochemical solutions and physical or mechanical processing steps. In an attempt to simplify the fluidic requirements for integrated biodetection systems, we used tunable surface microparticles both as an rRNA affinity purification resin in a renewable microcolumn sample preparation system and as the sensor surface in a flow cytometer detector. The tunable surface detection limits in both low- and high-salt buffers were 1 ng of total RNA ( approximately 10(4) cell equivalents) in 15-min test tube hybridizations and 10 ng of total RNA ( approximately 10(5) cell equivalents) in hybridizations with the automated system (30-s contact time). RNA fragmentation was essential for achieving tunable surface suspension array specificity. Chaperone probes reduced but did not completely eliminate cross-hybridization, even with probes sharing <50% identity to target sequences. Nonpurified environmental extracts did not irreparably affect our ability to classify color-coded microparticles, but residual environmental constituents significantly quenched the Alexa-532 reporter fluor. Modulating surface charge did not influence the interaction of soluble environmental contaminants with conjugated beads. The automated system greatly reduced the effects of fluorescence quenching, especially in the soil background. The automated system was as efficacious as manual methods for simultaneous sample purification, hybridization, and washing prior to flow cytometry detection. The implications of unexpected target cross-hybridization and fluorescence quenching are discussed relative to the design and implementation of an integrated microbial monitoring system.

Automation↗
PubMed2002

[Expression of plasmid pcDNA3-gtfB in mammalian cell].

OBJECTIVE: This study aimed at investigating the transcription and expression of recombined plasmid pcDNA3-gtfB which encoding multiple glucosyltransferase-B antigenic gene, and the feasibility of the pcDNA3-gtfB used as gene vaccine. METHODS: The pcDNA3-gtfB was transfected into mammalian cell COS-1 with liposome. The total RNA of COS-1 cell transfected by pcDNA3-gtfB was extracted and purified. Using the total RNA as template, the transcription of pcDNA3-gtfB was assayed by reverse transcription polymerase chain reaction (RT-PCR). The expression product of pcDNA3-gtfB was identified with 5% SDS-PAGE, and then assayed using Western-blotting. The expression product of pcDNA3-gtfB was also assayed by using LSAB method, and cell transfected by pcDNA3 as the negative control. RESULTS: Identified by agarose gel electrophoresis, the target gene fragment had the same molecular size (3.6 kb) as it was predicted, and it indicated that pcDNA-3gtfB was correctly transcribed into mammalian cells. Proved by SDS-PAGE, the molecular weight of the expression product (116-212 kD) was also the same as it was supposed to be. It was also indicated by Western-blotting and LSAB assay that the expression product induced immunizing response. CONCLUSION: As gene vaccine, it is importance that the recombined plasmid could be correctly transcribed and expressed in mammalian cells. It was suggested by RT-PCR, LSAB and Western-blotting that recombined plasmid pcDNA3-gtfB could be correctly transcribed and expressed in mammalian cells, and the expression product could induce immunizing response, which support its use as gene vaccine candidates in the development of anticaries vaccines.

Animals↗
PubMed1991

Severe reductions in transcripts for cytochrome c oxidase during erythropoiesis in vitro do not lead to inactive mitochondria in reticulocytes.

At some stage during erythroid cell differentiation proliferation of the cell stops and its organelles are removed and degraded. We wanted to know how mitochondrial function correlated with the synthesis of products necessary for functional mitochondria. We studied the time course of the presence of a nuclear and a mitochondrial transcript for the mitochondrial enzyme cytochrome c oxidase as well as that of the enzyme activity itself in differentiating murine splenic erythroid progenitors (erythroid colony-forming units, CFU-E) in vitro. Whereas the amount of total RNA as well as the transcripts for subunits II and IV of cytochrome c oxidase (COX II and COX IV) per cell decreased to low levels, the amount of globin mRNA increased from zero in CFU-E (t = 0) to high levels in late erythroblasts (21 h). Thus, RNA synthesis as such was not inhibited. The cytochrome c oxidase activity also declined. In the total culture, total RNA as well as the mRNAs for COX II and IV decreased after 7 h. The enzyme activity increased until 21 h and decreased after that. The early decrease of the transcripts, followed after a lag phase of 14 h by a decrease in enzyme activity, ultimately does not result in inactive mitochondria in the reticulocyte stage, as was shown with a mitochondria-specific fluorescent probe.

Animals↗
PubMed1987

c-myc expression in the thyroid. I: Normal, adenomatous, and cancerous thyroid tissue.

Recent investigations have suggested that myc oncogene expression may be important in the development or progression of thyroid tumors. The purposes of the present study were to assess cellular (c)-myc expression in thyroid adenomas (n = 5), as well as in thyroid cancer (n = 4) and in normal thyrocytes (n = 7). Total RNA was prepared by extraction with guanididium thiocyanate and ultracentrifugation through a CsCl2 cushion. 30 micrograms total RNA was size fractionated on a 1% (w/v) agarose/formaldehyde gel and transferred to nylon membranes. These membranes were hybridized to a 32P-labelled third exon c-myc DNA. Following hybridization, blots were washed under high stringency and subjected to autoradiography; radioautographic bands were assessed visually or were quantitated by scanning densitometry. Nodular tissue had approximately the same degree of expression of the 2.4 Kb c-myc message as the surrounding normal tissue from the same gland (0.66 +/- 0.09 vs. 1.0 +/- 0.26, respectively); normal thyrocytes were capable in every instance of expressing the 2.4 Kb c-myc message. Thyroid cancer tissue expressed this message (0.91 +/- 0.17) but only at a level comparable to normal tissue. No other bands of hybridization were detected in any samples. We conclude that c-myc oncogene expression is comparable in normal thyrocytes and in thyroid nodules or thyroid cancer samples. These findings support a role for c-myc in both normal and neoplastic thyrocyte growth.

Adenoma↗
PubMed1993

[Analysis of MDR1 (multidrug resistance) gene expression by RT-PCR].

Multidrug resistance to anticancer drugs proved to be related to the MDR1 gene which encodes the P-glycoprotein, an energy-dependent drug-efflux pump for lipophilic drugs. We investigated the expression of the MDR1 gene in clinical samples by RT-PCR. The subjects were all resected cases of 14 colorectal cancers, five gastric cancers, two esophageal cancers, two gallbladder cancers and 20 lung cancers. Adrenal gland was used as a positive control. Total RNA was extracted from a fresh tissue sample. The cDNA was synthesized from 1 microgram of total RNA using reverse transcriptase. With the above cDNA as the template, amplification of the 157-bp fragment of the MDR1 gene was performed using PCR. The PCR product was polyacrylamide gel-electrophoresed and ethidium bromide-stained. In addition, a dot blot analysis was performed to quantify the amount of PCR product. Since PCR was performed simultaneously under the same conditions, the PCR product was quantified at four stages, from (3+) to (-), to indicate the degree of expression of MDR1 mRNA. Adrenal gland showed (3+)-(2+) and colorectal cancer exhibited mostly (2+)-(1+). Both cancerous and non-cancerous areas evidenced a similar degree of expression in the cases of colorectal cancer. The MDR1 gene was expressed at low levels in other digestive tract cancers and in lung cancer. The levels of MDR1 expression revealed no correlation to either histological type or clinical stage. The present method may contribute to designing anti-cancer protocols.

Antineoplastic Agents↗
PubMed1984

Elastin mRNA levels during foetal development of sheep nuchal ligament and lung. Hybridization to complementary and cloned DNA.

Elastin mRNA levels were quantified in sheep nuchal ligament and lung during the latter half of foetal development with elastin-specific cDNA (complementary DNA) probes using both hybridization in solution (saturation analysis) and hybridization on a fixed support (Northern analysis). For the solution-hybridization studies, cDNA prepared from nuchal-ligament mRNA was enriched to 65% for elastin sequences by hybridizing it to its template at a R0t (mol X s X litre-1) value that included only the abundant class of mRNA sequences. Hybridization of this probe to RNA extracted from nuchal ligament between 70 and 138 days after conception demonstrated elastin sequences increased about 10-fold (from 0.047 to 0.438% of total RNA). In contrast, lung elastin mRNA levels increased only 3-fold (from 0.009 to 0.022% of total RNA) during the same period. Over this development period these values correspond to increases in the average number of elastin mRNA molecules from 950 to 20 000 molecules/ligament cell and from 130 to 330 molecules/lung cell. For Northern analysis, elastin mRNA was purified from near-term-sheep nuchal ligament on sucrose density gradients. Analysis of the translation products of this elastin mRNA showed that relative elastin precursor synthesis was at least 80% of total [3H]valine incorporation. The Mr of this elastin mRNA, determined by methylmercury-agarose-gel electrophoresis, was approx. 1.25 X 10(6). Northern hybridization of nuchal ligament and lung RNA to a [32P]cDNA probe, transcribed from this sucrose-gradient-purified elastin mRNA, confirmed the developmental changes in elastin mRNA levels detected by solution-hybridization techniques. The specificity of this method was confirmed by using a cloned elastin gene fragment. These studies demonstrate that elastin mRNA levels in organs such as nuchal ligament and lung increase with foetal development, but that there are significant differences in the average cellular elastin mRNA content of these two organs.

Animals↗
PubMed2006

A time course study demonstrating RNA stability in postmortem skin.

Knowledge of the factors regulating the rate of mRNA degradation, including postmortem delay, is important in determining the reliability of gene expression patterns in dermal tissue. Since RNA stability can be tissue dependent, this study evaluates the effect of postmortem interval on the integrity of total RNA or the levels of representative mRNA species in murine cutaneous tissue. Pieces of fresh skin tissue were excised for periods of 0-60 min from SKH-1 female hairless mice that were maintained at room temperature post-sacrifice. Total RNA was subsequently isolated and RNA integrity from each specimen was evaluated. Bioanalyzer profiles showed no apparent change in 28S/18S rRNA ratio or RNA integrity number at time points up to 60 min. Changes in mRNA expression levels of five selected genes were determined by real-time quantitative PCR. There were no statistical differences in the relative gene expressions of Ccnd1, Hif1alpha, cMyc and Cyr61 as a function of postmortem interval. Our data suggest that the molecular quality of cutaneous tissue is well preserved for at least 60 min after death, which can be regarded as important information for consideration of the order for tissue procurement in in vivo studies and acute ex vivo dermal studies.

Animals↗
PubMed1992

Changes in human muscle protein synthesis after resistance exercise.

The purpose of this study was to investigate the magnitude and time course for changes in muscle protein synthesis (MPS) after a single bout of resistance exercise. Two groups of six male subjects performed heavy resistance exercise with the elbow flexors of one arm while the opposite arm served as a control. MPS from exercised (ex) and control (con) biceps brachii was assessed 4 (group A) and 24 h (group B) postexercise by the increment in L-[1-13C]leucine incorporation into muscle biopsy samples. In addition, RNA capacity and RNA activity were determined to assess whether transcriptional and/or translational processes affected MPS. MPS was significantly elevated in biceps of the ex compared with the con arms of both groups (group A, ex 0.1007 +/- 0.0330 vs. con 0.067 +/- 0.0204%/h; group B ex 0.0944 +/- 0.0363 vs. con 0.0452 +/- 0.0126%/h). RNA capacity was unchanged in the ex biceps of both groups relative to the con biceps, whereas RNA activity was significantly elevated in the ex biceps of both groups (group A, ex 0.19 +/- 0.10 vs. con 0.12 +/- 0.05 micrograms protein.h-1.microgram-1 total RNA; group B, ex 0.18 +/- 0.06 vs. con 0.08 +/- 0.02 micrograms protein.h-1.microgram-1 total RNA). The results indicate that a single bout of heavy resistance exercise can increase biceps MPS for up to 24 h postexercise. In addition, these increases appear to be due to changes in posttranscriptional events.

Adult↗
PubMed1983

In vitro transcription from Bacillus subtilis nucleoids by homologous RNA polymerase.

The effect of DNA structural features on RNA synthesis was investigated. Purified Bacillus subtilis nucleoids templated from vegetative cells were transcribed by the homologous RNA polymerase using Hg-UTP as one of the nucleotide substrates. Low RNA polymerase/DNA ratios were used during transcription in order to avoid nonspecific initiations. The rate of synthesis of total RNA was 40% greater on nucleoid templates than on naked DNA. The proportion of asymmetric transcript synthesized on nucleoid templates (HvsL strand transcripts) was close to that observed in vivo, whereas with naked DNA this value was at least 3-times lower. The percentage of rRNA relative to the total RNA, synthesized in the in vitro system with the nucleoid template, approaches the rate of the in vivo transcription. The size of the RNA synthesized on nucleoids was large and heterogeneous while with naked DNA it was homogeneous and of about 6 S. Our results suggest that the supercoiled, folded nucleoids may retain some of the structural features responsible for the regulation of RNA synthesis in vivo.

Bacillus subtilis↗
PubMed2001

Poly(A) polymerase activity and RNA polyadenylation in Streptomyces coelicolor A3(2).

The Streptomyces coelicolor genome sequence was searched for open reading frames (ORFs) similar to Escherichia coli poly(A) polymerase I, revealing an ORF with 36% amino acid sequence identity to that protein. Mycelial extracts prepared from S. coelicolor cultures incorporated radioactive ATP into an acid-insoluble form, and some of the products of this incorporation had the properties expected of poly(A). [3H]-uridine and [3H]-adenosine were used to label the RNA in S. coelicolor cultures of different ages, and total RNA was fractionated by oligo dT cellulose chromatography. Approximately 3% of the total uridine-labelled RNA and 11% of the adenosine-labelled RNA were retained by the oligo dT cellulose columns. Enzymatic digestion of the retained RNA supported the conclusion that a significant fraction of the adenosine label was present in 3'-poly(A) chains. Measurement of poly(A) tail lengths by end labelling of total RNA and RNase digestion revealed a maximum length of approximately 18 residues. Radioactive cDNA prepared from the RNA fraction retained by oligo dT cellulose hybridized to the 16S and 23S genes from a streptomycete ribosomal RNA operon but not to the 5S gene. Reverse transcription-polymerase chain reaction (RT-PCR) revealed the presence of mRNAs in the RNA fraction retained by oligo dT cellulose.

Amino Acid Sequence↗