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At least 19 recordsLinked to original sources
PubMed1978

Gene enrichment using antibodies to DNA/RNA hybrids: purification and mapping of Dictyostelium discoideum rDNA.

Antibodies, shown to be specific for DNA/RNA hybrids, have been covalently attached to CNBr-activated Sepharose. The resultant affinity resin specifically binds DNA/RNA hybrids and has been used to enrich for the DNA which codes for rRNA in the slime mold Dictyostelium discoideum. By utilizing the technique of R-loop formation, DNA molecules containing the rRNA genes were isolated from total nuclear DNA in a double-stranded form. These rDNA molecules, which were recovered by high salt elution from the affinity resin, were typically 15-40 kbp in length, and thus contained DNA sequences adjacent to the selected sequences coding for the 17S and 26S rRNAs. In addition, evidence has been obtained concerning the structure of Dictyostelium rDNA which agrees with the finding (Taylor et al. (1977) ICN-UCLA Symp. Mol. Cell. Biol. 8, 309-313) that the rDNA molecules are not covalently attached to the chromosomes of this organism.

Chromatography, Affinity↗
PubMed2026

No Correlation Between Interferon Signaling and Cytosolic Mitochondrial DNA/RNA Leakage in Cultured Skin Fibroblasts of Patients With Mitochondrial Diseases.

Mitochondria have long been known to be involved in the regulation of innate immune response. We questioned whether cultured skin fibroblasts of patients suffering from mitochondrial diseases are valuable biological resources for the study of interferon signaling. Expression of interferon-stimulated genes was measured in control cells supplemented with interferon and in cultured fibroblasts of patients carrying pathogenic variants in mitochondrial disease-causing genes. Control fibroblasts showed a strong expression of interferon-stimulated genes in response to interferon, but only 43% of patients' fibroblasts displayed increased interferon stimulated genes scores. Cytosolic mitochondrial DNA and RNA were quantified by immunofluorescence and confocal microscopy. No correlation between elevated interferon response and cytosolic mitochondrial DNA or RNA release could be established. We found that cultured skin fibroblasts represent a valuable biological resource for the investigation of interferon signaling, but that abnormal interferon signaling is not always observed in patients with mitochondrial diseases. At variance to gene silencing in control fibroblasts, the lack of correlation between elevated interferon response and cytosolic mitochondrial DNA or RNA leakage in patients' fibroblasts questions the relevance of cellular models as illustrators of pathological situations in humans.

Humans↗
PubMed1976

Analysis of immunoglobulin genes: DNA/RNA hybridization with immunoglobulin kappa-chain mRNA and isolation and translation of hybridized RNA.

Immunoglobulin kappa-chain mRNA was hybridized with DNA in order to assess the kappa-gene frequency. Kappa-mRNA was purified from membrane-bound ribosomes of mouse myeloma MOPC-41 by poly (U) chromatography and isolation of a 13S RNA by successive sucrose density gradient centrifugations. The RNA coded for kappa-chain precursor molecules in cell-free protein synthesis and essentially no other proteins. MOPC-41 kappa-mRNA hybridized with MOPC-41, MPC-11, and Krebs DNA with the same kinetics: the majority of the hybrids was formed with rare or unique DNA sequences (Cot/2 450 to 900), a small portion with highly repetitive sequences (Cot/2 5--6). The slow hybrids were well matched and the rapid hybrids were mismatched by about 4%, regardless of the DNA used. It was further investigated whether the rapid hybrids contained translatable kappa-mRNA or were due to impurities in the RNA preparations. Kappa-mRNA and globin-mRNA (as an internal standard for a unique transcript) were hybridized with DNA to Cot 20 or 48, the hybridized and unhybridized RNA were isolated by hydroxyopatite-urea chromatography and, after removal of the DNA, translated in a cell-free system. The cell-free products were analyzed by SDS-polyacrylamide gel electrophoresis and immunoprecipitation. It was found that approximately equal quantities of translatable kappa- and globin-mRNA were hybridized maximally 1.7%). The results do not support the hypothesis that kappa-mRNA is a transcript of both repetitive and unique DNA sequences.

Animals↗
PubMed2026

Application of PathoChip to urine-derived nucleic acids for broad microbial profiling in men with suspected prostate cancer: setup of a methodological workflow and pilot feasibility study.

BACKGROUND: Urine-based liquid biopsy is an attractive non-invasive source of prostate cancer (PCa) biomarkers, but urinary microbiome studies have mainly relied on 16S rRNA sequencing or shotgun metagenomics. This pilot study optimized and evaluated a practical workflow using PathoChip - a broad-spectrum microarray designed to detect bacterial, viral, fungal, and parasitic signatures - for microbial profiling of urine sediments from men with suspected PCa, an application not previously established. METHODS: First-morning urine was collected without prostatic massage from 35 men scheduled for biopsy; 19 were diagnosed with PCa and 16 were biopsy-negative. Different urine volumes and extraction strategies were evaluated to optimize DNA/RNA recovery. A setup phase compared 25 ng versus 50 ng of urine DNA and RNA input. DNA/RNA isolated from human B cells was used as reference control. An analysis pipeline was developed to detect outlier probes and create a presence/absence matrix. Reproducibility was assessed via library yield, Pearson correlation, blank-control subtraction, outlier probe detection. Prevalence comparisons were performed between clinical groups. RESULTS: An 8 mL starting volume was chosen as consistently available from self-collected urine. Sequential DNA/RNA extraction using the AllPrep DNA/RNA Micro Kit from sediment provided the best balance between nucleic-acid recovery, purity, and clinical compatibility. Reducing the input from 50 ng to 25 ng preserved highly concordant hybridization profiles, with matched samples clustering together with strong correlations. Exploratory analysis revealed PCa- and grade-associated patterns involving Actinomycetaceae, Aerococcaceae, and Streptococcaceae, with Streptococcaceae enriched in PCa of higher grades (ISUP GG ≥ 2). Other signatures, including Mobiluncus, Prevotella, Rhodotorula, Hymenolepis, and JC polyomavirus, were broadly detected but not PCa-discriminating. CONCLUSIONS: PathoChip can be adapted to urine sediments, generating reproducible microbial profiles from limited DNA/RNA input without prostatic massage. This platform provides a quick and accessible approach to broad screening, extending beyond 16S rRNA sequencing by enabling simultaneous multi-kingdom detection. The observed PCa- and grade-associated patterns are hypothesis-generating and require validation in larger independent cohorts.

Pathochip↗
PubMed2026

Endosymbiotic theory of aging revisited: Age-related leakage of mitochondrial dsDNA/RNA stimulates cytosolic nucleic acid sensors which remodel the immune network and promote the aging process.

About 1.5-2 billion years ago, an endosymbiosis between aerobic α-proteobacteria and anaerobic archaeal cells generated mitochondria, i.e., organelles capable of producing oxidative energy. The bacterial genome was fundamentally reduced and a circular mitochondrial genome evolved containing mainly the genes coding for the subunits of the electron transport chain. Before the symbiotic event, there existed a virus-host co-evolution which involved the development of sensors for detecting dangerous viral DNA/RNA molecules. Endosymbiosis supplied eukaryotic cells not only with an oxidative powerhouse to allow the evolution of more complex multicellular organisms but it also meant that cells now housed an organelle which was able to generate reactive oxygen species (ROS) and to leak mitochondrial DNA (mtDNA) and double-stranded RNA (dsRNA) into the cytoplasm. There is now abundant evidence that during aging and age-related diseases mitochondria are prone to release both mtDNA and dsRNA. In the cytoplasm, mtDNA/dsRNA molecules activate a number of cytosolic nucleic acid sensors leading to the secretion of type-1 interferons (IFN) and many other cytokines which promote an age-related proinflammatory state. Currently, it is known that mtDNA can activate the cGAS-STING pathway, AIM2 inflammasomes, IFI16 receptors, and ZBP1 sensors and in addition mitochondrial dsRNA stimulates RIG-1/MDA5 signaling. Interestingly, there is abundant evidence that all these receptors are drivers of cellular senescence and inflammaging. For decades, there has been mounting evidence that mitochondria have a crucial role in the aging process. We will examine this question from the perspective of evolution and propose that mitochondrial evolution created an endogenic source for the leakage of dangerous mtDNA/dsRNA which subsequently stimulated cytosolic DNA/RNA sensors, an evolutionarily conserved viral defence mechanism. It seems that these two evolutionary events provided not only the basis for the inevitable process of aging but also ensuring the death of parental organisms.

Aging↗
PubMed1977

Estimation of gene reiteration from hybridization kinetics in moderate deoxyribonucleic acid excess.

Theoretical calculations were carried out to clarify how the DNA/RNA or the DNA/cDNA (complementary DNA) ratio in the hybridization reaction mixture affects the kinetics of DNA-RNA or DNA-cDNA reassociation, and theoretical formulae were derived as a function of these ratios. From these formulae, it was found that the DNA/RNA of the DNA/cDNA ratio did not much affect the initial reaction rates of hybridization, but greatly affected the terminal value for the extent of hybrid formation. Therefore the results obtained when one normalizes the experimental data for hydridization and derives the reiteration frequency from a number called the 'half Cot' (Cot 1/2) are not accurate, especially in the presence of a moderate excess of DNA. A simple method for the estimation of gene reiteration was demonstrated that did not use the half Cot value in the determination. This simple method is useful even if DNA-RNA or DNA/cDNA hybridization are done with a moderate excess of DNA. With mouse myeloma cells as a model system, the gene reiteration of the 28S rRNA cristron was determined.

DNA↗
PubMed2025

A SlEIN2-centered epigenetic network equilibrates fruit ripening and innate immunity in tomato.

Ethylene and DNA/RNA methylation serve as essential factors in controlling fruit ripening. In tomato, the mRNA N6-methyladenosine (m6A) demethylase SlALKBH2 regulates mRNA stability of the DNA 5-methylcytosine demethylase gene SlDML2 via modulating m6A modifications. However, the interplay between ethylene and these epigenetic marks remains unclear. Here, we show that SlDML2 expression is significantly inhibited in slein2 fruits, but remains unchanged in the high-order sleil mutant (sleil1 sleil2 sleil3/SlEIL3 sleil4 and sleil1 sleil2/SlEIL2 sleil3 sleil4) fruits, indicative of post-transcriptional regulation of SlDML2 expression by SlEIN2, a core ethylene signaling component acting upstream of the master transcription factors SlEILs. Interestingly, SlEIN2 preferentially regulates the asymmetric CHH methylation in promoters of several key ripening regulator genes. Mechanistically, SlEIN2 physically interacts with SlALKBH2, which promotes SlDML2 expression in a SlEIN2-dependent manner. Furthermore, SlAGO4A and SlAGO4B, components of the RNA-directed DNA methylation pathway, were upregulated in slein2 fruits. Silencing SlAGO4A/B in wild-type fruit caused precocious ripening with necrosis, indicative of hyperimmunity. Conversely, SlAGO4A/B silencing in slein2 markedly delayed this hyperimmunity. Taken together, our study reveals that ethylene, beyond transcriptional regulation, employs an elaborate epigenetic machinery mediated by the SlAGO4A/B-SlEIN2-SlALKBH2 module to balance fruit ripening and innate immunity.

Solanum lycopersicum↗
PubMed2025

A Step-by-Step Guide to Sequencing and Assembly of Complete Bacterial Genomes Using the Oxford Nanopore MinION.

The Oxford Nanopore (ONT) MinION enables sequencing of longer DNA/RNA fragments compared to other sequencers, such as Illumina, etc. This nanopore method provides distinct advantages for generating complete genome assemblies from microorganisms. Specifically, the R9.4 flow cells used for MinION sequencing have much lower error rates compared with earlier versions of the ONT platform. Coupled with base calling using Dorado software, higher-quality long reads can now be generated for complete bacterial genome assembly. In this chapter, we describe a detailed MinION method to assemble a complete genome from a microorganism, polish the final assembly, and evaluate the genome quality using various software tools. Because of the low cost for MinION sequencing, this platform could be an asset for virtually any laboratory interested in generating complete genomes from microorganisms.

Genome, Bacterial↗
PubMed1975

Visualization of nucleolar organizer regions im mammalian chromosomes using silver staining.

A simple ammoniacal silver staining procedure, designated Ag-AS, differentially stains the chromosomal locations of ribosomal DNA in certain mammalian species. This was critically demonstrated by Ag-AS staining of the nucleolus organizer regions in karyotypes of the same species and cell lines used for locating the ribosomal cistrons by DNA/RNA in situ hybridization. With Ag-AS, silver stained NORs (Ag-NORs) are visualized as black spherical bodies on yellow-brown chromosome arms. Ag-NORs were visualized throughout mitosis at the secondary constrictions in the rat kangaroo, Seba's fruit bat, Indian muntjac, and Rhesus monkey. The Chinese hamster and cattle have telomeric Ag-NORs, the mouse subcentromeric Ag-NORs, and the field vole Ag-NORs as minute short arms or choromosomal satellites. Ag-NORs occur at both secondary constrictions and at telomeres in the cotton rat. Variability in Ag-NOR pattern included differences in the number of Ag-NORs per cell within a cell population, size of Ag-NORs among chromosomes of a complement, and presence of Ag-NOR on particular chromosomes in two cell lines of the Chinese hamster. The available cytochemical data suggest that the Ag-AS reaction stains chromosomal proteins at the NOR rather than the rDNA itself.

Animals↗
PubMed1975

Experimental necrosis and arrest of proliferation of Schwann cells by cytosine arabinoside.

In developing rat cervical sympathetic trunks, Schwann cells proliferate intensely during the first week after birth but axonal populations do not increase. Thus, experimental inhibition of DNA synthesis should affect Schwann cells and spare axons whose cell bodies are not dividing. The present investigation was aimed at determining the effects of an inhibitor of DNA synthesis-cytosine arabinoside (ara-C)--on axons and Schwann cells in developing nerves. Ara-C (60 mg kg(-1) body weight) was injected subcutaneously to newborn rats every six hours for 36 hours. At intervals from 2--4 days of age, animals were given tritiated thymidine (4 muCi per gram body weight) to label Schwann cells in synthesis phase. One hour later rats were killed by systemic perfusion of phosphate buffered glutaraldehyde. Cervical sympathetic trunks (CST's) and sciatic nerves were removed and processed for radioautography and electron microscopy (EM). Labelled and unlabelled Schwann cell nuclei were counted to determine the labelling index (LI%) for each nerve. By the end of ara-C treatment there was almost complete absence of labelling but LI's rose sharply 24 hours after discontinuing ara-C. By EM axons appeared normal; Schwann cells, however, showed prominent nuclear and cytoplasmic changes consisting of nuclear degeneration, dilatation of rough endoplasmic reticulum and increased cytoplasmic density. Ara-C, by suppressing proliferation and causing necrosis of Schwann cells but sparing axons, results in a developmental alteration of axon-Schwann cell relationships. It is suggested that the pathogenetic mechanism involves an inbalance in DNA/RNA synthesis metabolism.

Animals↗
PubMed2026

Molecular characterization of salivary cancers: Patterns of genomic alterations and potential for impact on therapeutic choices.

BACKGROUND: Salivary cancers are rare malignancies with diverse histologies, molecular landscape, and limited effective systemic therapy options. Recent tumour genomics research has identified driver alterations in salivary gland cancers that have led to personalized therapy approaches. The primary objective was to perform molecular characterization using next generation sequencing (NGS) panel and evaluate the potential impact of results on clinical decision-making and treatment outcomes. METHODS: Patients with locally advanced or incurable metastatic salivary cancers suitable for systemic therapy underwent NGS tumour testing with an amplicon-based DNA/RNA NGS panel. Patient demographics, baseline characteristics, treatment and treatment outcomes were retrospectively collected. RESULTS: From 2021 to 2024, 58 advanced salivary cancer patients underwent molecular characterization of their tumour. Baseline characteristics at diagnosis: male 60%, median age 67, most common histologies; adenoid cystic 27%, salivary duct 19% and mucoepidermoid 12%. PIK3CA alterations were the most common molecular finding across all subtypes 22% (13/58) and were enriched in salivary duct carcinoma 73% (8/11). Other alterations identified were: ERBB2 (4), EGFR (2), HRAS (3), NTRK3 (2), BRAF p.V600E (1), and RET (1). Immunohistochemistry identified androgen receptor positivity across salivary cancer subtypes in 8/19 and HER2 positivity in 2/20 tested. Twenty-two patients received systemic therapy prior to NGS results for incurable/metastatic disease, first line treatments included 69% chemotherapy, 18% anti-androgen, 9% lenvatinib, 4% trial. CONCLUSION: Molecular characterization of salivary cancers identified targetable alterations in 37% of patients. The identification of potential therapeutic targets offers the opportunity for expanded treatment options to benefit salivary gland cancer patients.

Metastatic salivary gland cancer↗
PubMed2024

High yield of monogenic short stature in children from Kurdistan, Iraq: A genetic testing algorithm for consanguineous families.

PURPOSE: Genetic testing in consanguineous families advances the general comprehension of pathophysiological pathways. However, short stature (SS) genetics remain unexplored in a defined consanguineous cohort. This study examines a unique pediatric cohort from Sulaimani, Iraq, aiming to inspire a genetic testing algorithm for similar populations. METHODS: Among 280 SS referrals from 2018-2020, 64 children met inclusion criteria (from consanguineous families; height ≤ -2.25 SD), 51 provided informed consent (30 females; 31 syndromic SS) and underwent investigation, primarily via exome sequencing. Prioritized variants were evaluated by the American College of Medical Genetics and Genomics standards. A comparative analysis was conducted by juxtaposing our findings against published gene panels for SS. RESULTS: A genetic cause of SS was elucidated in 31 of 51 (61%) participants. Pathogenic variants were found in genes involved in the GH-IGF-1 axis (GHR and SOX3), thyroid axis (TSHR), growth plate (CTSK, COL1A2, COL10A1, DYM, FN1, LTBP3, MMP13, NPR2, and SHOX), signal transduction (PTPN11), DNA/RNA replication (DNAJC21, GZF1, and LIG4), cytoskeletal structure (CCDC8, FLNA, and PCNT), transmembrane transport (SLC34A3 and SLC7A7), enzyme coding (CYP27B1, GALNS, and GNPTG), and ciliogenesis (CFAP410). Two additional participants had Silver-Russell syndrome and 1 had del22q.11.21. Syndromic SS was predictive in identifying a monogenic condition. Using a gene panel would yield positive results in only 10% to 33% of cases. CONCLUSION: A tailored testing strategy is essential to increase diagnostic yield in children with SS from consanguineous populations.

Humans↗
PubMed1975

Quantitative autoradiographic studies on the competition of diethylnitrosamine (DENA) and 9,10-dimethyl-1,2-benzanthracene (DMBA) in the liver cell of CBA-mice.

In CBA-mice the competition of DENA and DMBA was studied by quantitative autoradiography. During the precancerous phase in DENA-pretreated animals the rate of DMBA-incorporation into DNA/RNA and nuclear proteins was lower as compared to the controls without DENA-pretreatment. Independent of DENA-pretreatment the rate of DMBA-incorporation into the cytoplasm was significantly enhanced in hepatectomized animals. In this experiment the skin as a target organ did not show any quantitatively measurable DMBA-incorporation despite of prolonged autoradiographic exposition time.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1978

Alcohol and nutrition.

Alcoholic patients frequently have evidence of nutritional deficiency the consequences of which may be seen in all systems of the body. Alcoholism is theoretically a completely preventable disorder which requires more attention by the general public, practising physicians and research workers. Rehabilitation of the established alcoholic will sometimes be limited by failure to modify behaviour or because of nutritionally induced brain damage but we are beginning to understand some of the mechanisms by which malnutrition evolves (Figure 2). Better methods must be developed to limit alcohol-induced tissue injury in patients whose drinking cannot be controlled. The final mechanisms of liver injury remain to be established. Cirrhosis may be induced in animals ingesting a good diet but this does not ensure adequate delivery and utilization of nutrients at the subcellular level. Cirrhosis takes a long time to evolve and the natural history, including longitudinal nutritional profiles in man, has not been established. Therefore, although normal liver morphology is sometimes seen in alcoholics with gross stigmata of malnutrition suggesting that factors other than malnutrition are important, it may be that critical nutrients have not been deficient for long enough in these individuals or severe depletion has been intermittent. Whether or not malnutrition is of decisive importance in the toxicity of alcoholic liver injury in man, adequate replacement is essential for protection and repair of liver cells. Established daily minimal requirements are not adequate for patients with active liver disease. Hepatocyte injury reduces the capacity of this major storage site and causes release of vitamins (co-enzymes) into the circulation in the form of holoenzymes. Liver damage reduces the conversion of nutrients into their metabolically useful forms required for catabolic processes and to meet increased needs for DNA/RNA synthesis necessary for repair of damaged cells and to replace necrotic cells. The choice and route of therapy must take account of the patient's metabolic needs and their absorptive defects. The effects of alcohol and maternal undernutrition on the fetus/neonate may cause intra-uterine death or varying degrees of brain damage, thus limiting the potential of the next generation.

Alcoholism↗
PubMed1979

Determination of the size of rat ribosomal deoxyribonucleic acid repeating units by electron microscopy.

The empoyment of a novel method of affinity chromatography, which makes use of antibodies that specifically bind DNA/RNA hybrids, has made it possible to enrich for rat rDNA molecules which contain R loops formed with the 18S and 28S rRNAs. An approximately 150-fold enrichment of the ratrRNA coding sequences was obtained by this affinity chromatography procedure. This degree of enrichment made it possible to visualize these R loop containing molecules in the electron microscope and, thus, to obtain a map of the transcribed and spacer regions of rat rDNA. Eleven of the molecules that were observed contained either 3 or 4 R loops, or else 2 R loops separated by a long spacer. Thus, these molecules provided direct information in regard to the length of rat rDNA repeating units. The mean length of the repeating units was 37.2 kbp with a standard deviation of 1.3 kbp. Within the errors of the measurements, these could all represent repeating units of exactly the same length, although a certain degree of length heterogeneity, possibly up to 4 or 5 kbp, cannot be ruled out by the data. If significantly longer or shorter rDNA repeating units exist in the rat genome, they are probably much less common than the 37.2 kbp unit. These electron microscopic measurements provide the most definitive data yet available on the size of the repeating units of mammalian rRNA genes.

Animals↗
PubMed2026

Symmetric and near-symmetric cyanine probes for G-quadruplexes: molecular recognition, signal transduction, and biological applications.

G-quadruplexes (G4s) are dynamic noncanonical nucleic-acid structures involved in genome maintenance, transcription, RNA metabolism, and mitochondrial function, and are implicated in disease-associated processes. Symmetric and near-symmetric cyanines are versatile platforms for G4 recognition because their polymethine length, terminal heterocycles, charge distribution, conformational freedom, and supramolecular organization can be systematically tuned within related scaffolds. This review discusses how these structural features control G4 recognition and optical signal transduction through terminal G-tetrad stacking, loop and groove contacts, restriction of molecular motion, and aggregate reorganization. We first summarize in vitro recognition, structural discrimination, and G4-mediated sensing, and then discuss DNA and RNA G4 imaging, G4-associated biological processes, and emerging in vivo applications. Particular attention is given to several distinctions that are essential for interpreting probe performance: binding affinity versus fluorescence activation, topology preference versus DNA/RNA selectivity, organelle accumulation versus molecular targeting, and imaging contrast versus biological validation. Overall, molecular symmetry is considered a tunable design variable rather than a direct predictor of performance. Future studies should emphasize matched structural series, reversible and minimally perturbing probes, optical readouts that are less dependent on probe concentration, clear separation of DNA and RNA contributions, and standardized validation across solution, cellular, and whole-organism studies.

Journal Article↗
PubMed1976

Elimination of double strand nuclease activity from S1 nuclease prepared from crude alpha amylase.

Single strand-specific s1 nuclease prepared as previously described from crude alpha amylase by DEAE-cellulose chromatography also contains nuclease which degrades double strand nucleic acid. The double strand activity can be removed by repeating the DEAE-cellulose chromatography procedure at least two additional times. S1 nuclease prepared by this procedure does not degrade double strand sheared DNA as measured by Sephadex chromatography. Under the same conditions single strand DNA is completely degraded. Thus, S1 nuclease prepared by this procedure is suitable for use in removing single strand regions in DNA/DNA duplexes and DNA/RNA hybrids.

Amylases↗
PubMed1977

Immunochemical isolation of gamma-globulin mRNA and estimation of immunoglobulin gene reiteration.

The polyribosomes synthesizing gamma-globulin have been isolated by the achievement of specific precipitation using bentonite-treated anti-IgG antibody. The RNA extracted from the immunochemically precipitated polysomes was tested for its ability to direct the synthesis of proteins in a cell-free system. The specific gamma-globulin-synthesizing activity (cpm of gamma-globulin synthesized/microgram RNA) of this RNA was 10-fold greater than that from total polysomes. gamma-globulin mRNA (messenger RNA) isolated by immunoprecipitation was more than 89% pure with respect to contamination by other species of mRNA. The products synthesized by the cell-free system were also analyzed by sodium dodecyl sulphate(SDS)-polyacrylamide gel electrophoresis. This RNA has been hybridized with mouse myeloma DNA. The estimation of immunoglobulin gene reiteration was carried out using hybridization kinetics with consideration given to the DNA/RNA ratio since the estimation from the "half Cot value" is not accurate. The results suggest that in the mouse there are about 20 copies per subgroup of genes coding for the variable region of the H and L chains.

Alleles↗