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- MicroRNAs (13)
- Caenorhabditis elegans (10)
- Caenorhabditis elegans Proteins (7)
- RNA, Viral (6)
- Carrier Proteins (3)
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- Gene Expression Regulation, Developmental (3)
- MicroRNA (3)
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- Biosynthesis (1)
- Cell Cycle (1)
- Cell Differentiation (1)
- Coronary Artery Disease (1)
- DNA-Binding Proteins (1)
- Dauer (1)
- Development (1)
- Drosophila (1)
- Drosophila Proteins (1)
- Drosophila melanogaster (1)
- Extracellular RNA (1)
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Articles 1 - 29 of 29
Full-Text Articles in Biochemistry, Biophysics, and Structural Biology
Comparison Of Rna Isolation And Associated Methods For Extracellular Rna Detection By High-Throughput Quantitative Polymerase Chain Reaction, Kahraman Tanriverdi, Alper Kucukural, Ekaterina Mikhalev, Selim E. Tanriverdi, Rosalind Lee, Victor R. Ambros, Jane Freedman
Comparison Of Rna Isolation And Associated Methods For Extracellular Rna Detection By High-Throughput Quantitative Polymerase Chain Reaction, Kahraman Tanriverdi, Alper Kucukural, Ekaterina Mikhalev, Selim E. Tanriverdi, Rosalind Lee, Victor R. Ambros, Jane Freedman
Victor R. Ambros
MicroRNAs (miRNAs) are small noncoding RNA molecules that function in RNA silencing and posttranscriptional regulation of gene expression. miRNAs in biofluids are being used for clinical diagnosis as well as disease prediction. Efficient and reproducible isolation methods are crucial for extracellular RNA detection. To determine the best methodologies for miRNA detection from plasma, the performance of four RNA extraction kits, including an in-house kit, were determined with miScript miRNA assay technology; all were measured using a high-throughput quantitative polymerase chain reaction (qPCR) platform (BioMark System) with 90 human miRNA assays. In addition, the performances of complementary DNA (cDNA) and preamplification …
Staufen Negatively Modulates Microrna Activity In Caenorhabditis Elegans, Zhiji Ren, Isana Veksler-Lublinsky, David Morrissey, Victor Ambros
Staufen Negatively Modulates Microrna Activity In Caenorhabditis Elegans, Zhiji Ren, Isana Veksler-Lublinsky, David Morrissey, Victor Ambros
Victor R. Ambros
The double-stranded RNA-binding protein Staufen has been implicated in various post-transcriptional gene regulatory processes. Here we demonstrate that the Caenorhabditis elegans homolog of Staufen, STAU-1, functionally interacts with microRNAs. Loss-of-function mutations of stau-1 significantly suppress phenotypes of let-7 family microRNA mutants, a hypomorphic allele of dicer and a lsy-6 microRNA partial loss-of-function mutant. Furthermore, STAU-1 modulates the activity of lin-14, a target of lin-4 and let-7 family microRNAs, and this modulation is abolished when the 3' untranslated region of lin-14 is removed. Deep sequencing of small RNA cDNA libraries reveals no dramatic change in the levels of microRNAs, or other …
Biodistribution And Function Of Extracellular Mirna-155 In Mice, Shashi Bala, Timea Csak, Fatemeh Momen-Heravi, Dora Lippai, Karen Kodys, Donna Catalano, Abhishek Satishchandran, Victor R. Ambros, Gyongyi Szabo
Biodistribution And Function Of Extracellular Mirna-155 In Mice, Shashi Bala, Timea Csak, Fatemeh Momen-Heravi, Dora Lippai, Karen Kodys, Donna Catalano, Abhishek Satishchandran, Victor R. Ambros, Gyongyi Szabo
Victor R. Ambros
Circulating miRNAs can be found in extracellular vesicles (EV) and could be involved in intercellular communication. Here, we report the biodistribution of EV associated miR-155 using miR-155 KO mouse model. Administration of exosomes loaded with synthetic miR-155 mimic into miR-155 KO mice resulted in a rapid accumulation and clearance of miR-155 in the plasma with subsequent distribution in the liver, adipose tissue, lung, muscle and kidney (highest to lowest, respectively). miR-155 expression was detected in isolated hepatocytes and liver mononuclear cells of recipient KO mice suggesting its cellular uptake. In vitro, exosome-mediated restoration of miR-155 in Kupffer cells from miR-155 …
Control Of Stem Cell Self-Renewal And Differentiation By The Heterochronic Genes And The Cellular Asymmetry Machinery In Caenorhabditis Elegans, Omid F. Harandi, Victor Ambros
Control Of Stem Cell Self-Renewal And Differentiation By The Heterochronic Genes And The Cellular Asymmetry Machinery In Caenorhabditis Elegans, Omid F. Harandi, Victor Ambros
Victor R. Ambros
Transitions between asymmetric (self-renewing) and symmetric (proliferative) cell divisions are robustly regulated in the context of normal development and tissue homeostasis. To genetically assess the regulation of these transitions, we used the postembryonic epithelial stem (seam) cell lineages of Caenorhabditis elegans. In these lineages, the timing of these transitions is regulated by the evolutionarily conserved heterochronic pathway, whereas cell division asymmetry is conferred by a pathway consisting of Wnt (Wingless) pathway components, including posterior pharynx defect (POP-1)/TCF, APC related/adenomatosis polyposis coli (APR-1)/APC, and LIT-1/NLK (loss of intestine/Nemo-like kinase). Here we explore the genetic regulatory mechanisms underlying stage-specific transitions between self-renewing …
The Decapping Scavenger Enzyme Dcs-1 Controls Microrna Levels In Caenorhabditis Elegans, Gabriel Bosse, Stefan Ruegger, Maria Ow, Alejandro Vasquez-Rifo, Evelyne Rondeau, Victor Ambros, Helge Grosshans, Martin Simard
The Decapping Scavenger Enzyme Dcs-1 Controls Microrna Levels In Caenorhabditis Elegans, Gabriel Bosse, Stefan Ruegger, Maria Ow, Alejandro Vasquez-Rifo, Evelyne Rondeau, Victor Ambros, Helge Grosshans, Martin Simard
Victor R. Ambros
In metazoans, microRNAs play a critical role in the posttranscriptional regulation of genes required for cell proliferation and differentiation. MicroRNAs themselves are regulated by a multitude of mechanisms influencing their transcription and posttranscriptional maturation. However, there is only sparse knowledge on pathways regulating the mature, functional form of microRNA. Here, we uncover the implication of the decapping scavenger protein DCS-1 in the control of microRNA turnover. In Caenorhabditis elegans, mutations in dcs-1 increase the levels of functional microRNAs. We demonstrate that DCS-1 interacts with the exonuclease XRN-1 to promote microRNA degradation in an independent manner from its known decapping scavenger …
Developmental Decline In Neuronal Regeneration By The Progressive Change Of Two Intrinsic Timers, Yan Zou, Hui Chiu, Anna Zinovyeva, Victor Ambros, Chiou-Fen Chuang, Chieh Chang
Developmental Decline In Neuronal Regeneration By The Progressive Change Of Two Intrinsic Timers, Yan Zou, Hui Chiu, Anna Zinovyeva, Victor Ambros, Chiou-Fen Chuang, Chieh Chang
Victor R. Ambros
Like mammalian neurons, Caenorhabditis elegans neurons lose axon regeneration ability as they age, but it is not known why. Here, we report that let-7 contributes to a developmental decline in anterior ventral microtubule (AVM) axon regeneration. In older AVM axons, let-7 inhibits regeneration by down-regulating LIN-41, an important AVM axon regeneration-promoting factor. Whereas let-7 inhibits lin-41 expression in older neurons through the lin-41 3' untranslated region, lin-41 inhibits let-7 expression in younger neurons through Argonaute ALG-1. This reciprocal inhibition ensures that axon regeneration is inhibited only in older neurons. These findings show that a let-7-lin-41 regulatory circuit, which was previously …
The Evolution Of Our Thinking About Micrornas, Victor Ambros
The Evolution Of Our Thinking About Micrornas, Victor Ambros
Victor R. Ambros
Our appreciation of the significance of microRNAs to biology at large continues to be an evolving process.
Victor Ambros: The Broad Scope Of Micrornas. Interview By Caitlin Sedwick, Victor R. Ambros
Victor Ambros: The Broad Scope Of Micrornas. Interview By Caitlin Sedwick, Victor R. Ambros
Victor R. Ambros
Interview with Victor Ambros, who studies how microRNAs impact development.
Mutations In Conserved Residues Of The C. Elegans Microrna Argonaute Alg-1 Identify Separable Functions In Alg-1 Mirisc Loading And Target Repression, Anna Y. Zinovyeva, Samir Bouasker, Martin J. Simard, Christopher M. Hammell, Victor R. Ambros
Mutations In Conserved Residues Of The C. Elegans Microrna Argonaute Alg-1 Identify Separable Functions In Alg-1 Mirisc Loading And Target Repression, Anna Y. Zinovyeva, Samir Bouasker, Martin J. Simard, Christopher M. Hammell, Victor R. Ambros
Victor R. Ambros
microRNAs function in diverse developmental and physiological processes by regulating target gene expression at the post-transcriptional level. ALG-1 is one of two Caenorhabditis elegans Argonautes (ALG-1 and ALG-2) that together are essential for microRNA biogenesis and function. Here, we report the identification of novel antimorphic (anti) alleles of ALG-1 as suppressors of lin-28(lf) precocious developmental phenotypes. The alg-1(anti) mutations broadly impair the function of many microRNAs and cause dosage-dependent phenotypes that are more severe than the complete loss of ALG-1. ALG-1(anti) mutant proteins are competent for promoting Dicer cleavage of microRNA precursors and for associating with and stabilizing microRNAs. However, …
The Developmental Timing Regulator Hbl-1 Modulates The Dauer Formation Decision In Caenorhabditis Elegans, Xantha Karp, Victor Ambros
The Developmental Timing Regulator Hbl-1 Modulates The Dauer Formation Decision In Caenorhabditis Elegans, Xantha Karp, Victor Ambros
Victor R. Ambros
Animals developing in the wild encounter a range of environmental conditions, and so developmental mechanisms have evolved that can accommodate different environmental contingencies. Harsh environmental conditions cause Caenorhabditis elegans larvae to arrest as stress-resistant "dauer" larvae after the second larval stage (L2), thereby indefinitely postponing L3 cell fates. HBL-1 is a key transcriptional regulator of L2 vs. L3 cell fate. Through the analysis of genetic interactions between mutations of hbl-1 and of genes encoding regulators of dauer larva formation, we find that hbl-1 can also modulate the dauer formation decision in a complex manner. We propose that dynamic interactions between …
Mir-14 Regulates Autophagy During Developmental Cell Death By Targeting Ip3-Kinase 2, Charles Nelson, Victor Ambros, Eric Baehrecke
Mir-14 Regulates Autophagy During Developmental Cell Death By Targeting Ip3-Kinase 2, Charles Nelson, Victor Ambros, Eric Baehrecke
Victor R. Ambros
Macroautophagy (autophagy) is a lysosome-dependent degradation process that has been implicated in age-associated diseases. Autophagy is involved in both cell survival and cell death, but little is known about the mechanisms that distinguish its use during these distinct cell fates. Here, we identify the microRNA miR-14 as being both necessary and sufficient for autophagy during developmentally regulated cell death in Drosophila. Loss of miR-14 prevented induction of autophagy during salivary gland cell death, but had no effect on starvation-induced autophagy in the fat body. Moreover, misexpression of miR-14 was sufficient to prematurely induce autophagy in salivary glands, but not in …
Circulating Micrornas In Cardiovascular Disease, David Mcmanus, Victor Ambros
Circulating Micrornas In Cardiovascular Disease, David Mcmanus, Victor Ambros
Victor R. Ambros
Comment on: Transcoronary concentration gradients of circulating microRNAs. [Circulation. 2011]
Micrornas And Developmental Timing, Victor Ambros
Micrornas And Developmental Timing, Victor Ambros
Victor R. Ambros
MicroRNAs regulate temporal transitions in gene expression associated with cell fate progression and differentiation throughout animal development. Genetic analysis of developmental timing in the nematode Caenorhabditis elegans identified two evolutionarily conserved microRNAs, lin-4/mir-125 and let-7, that regulate cell fate progression and differentiation in C. elegans cell lineages. MicroRNAs perform analogous developmental timing functions in other animals, including mammals. By regulating cell fate choices and transitions between pluripotency and differentiation, microRNAs help to orchestrate developmental events throughout the developing animal, and to play tissue homeostasis roles important for disease, including cancer.
Dauer Larva Quiescence Alters The Circuitry Of Microrna Pathways Regulating Cell Fate Progression In C. Elegans, Xantha Karp, Victor Ambros
Dauer Larva Quiescence Alters The Circuitry Of Microrna Pathways Regulating Cell Fate Progression In C. Elegans, Xantha Karp, Victor Ambros
Victor R. Ambros
In C. elegans larvae, the execution of stage-specific developmental events is controlled by heterochronic genes, which include those encoding a set of transcription factors and the microRNAs that regulate the timing of their expression. Under adverse environmental conditions, developing larvae enter a stress-resistant, quiescent stage called 'dauer'. Dauer larvae are characterized by the arrest of all progenitor cell lineages at a stage equivalent to the end of the second larval stage (L2). If dauer larvae encounter conditions favorable for resumption of reproductive growth, they recover and complete development normally, indicating that post-dauer larvae possess mechanisms to accommodate an indefinite period …
Mirwip: Microrna Target Prediction Based On Microrna-Containing Ribonucleoprotein-Enriched Transcripts, Molly Hammell, Dang Long, Liang Zhang, Andrew Lee, C. Steven Carmack, Min Han, Ye Ding, Victor Ambros
Mirwip: Microrna Target Prediction Based On Microrna-Containing Ribonucleoprotein-Enriched Transcripts, Molly Hammell, Dang Long, Liang Zhang, Andrew Lee, C. Steven Carmack, Min Han, Ye Ding, Victor Ambros
Victor R. Ambros
Target prediction for animal microRNAs (miRNAs) has been hindered by the small number of verified targets available to evaluate the accuracy of predicted miRNA-target interactions. Recently, a dataset of 3,404 miRNA-associated mRNA transcripts was identified by immunoprecipitation of the RNA-induced silencing complex components AIN-1 and AIN-2. Our analysis of this AIN-IP dataset revealed enrichment for defining characteristics of functional miRNA-target interactions, including structural accessibility of target sequences, total free energy of miRNA-target hybridization and topology of base-pairing to the 5' seed region of the miRNA. We used these enriched characteristics as the basis for a quantitative miRNA target prediction method, …
Circulating Cell And Plasma Microrna Profiles Differ Between Non-St-Segment And St-Segment-Elevation Myocardial Infarction, Jeanine Ward, Nada Esa, Rahul Pidikiti, Jane E. Freedman, John F. Keaney, Kahraman Tanriverdi, Olga Vitseva, Victor R. Ambros, Rosalind Lee, David D. Mcmanus
Circulating Cell And Plasma Microrna Profiles Differ Between Non-St-Segment And St-Segment-Elevation Myocardial Infarction, Jeanine Ward, Nada Esa, Rahul Pidikiti, Jane E. Freedman, John F. Keaney, Kahraman Tanriverdi, Olga Vitseva, Victor R. Ambros, Rosalind Lee, David D. Mcmanus
Victor R. Ambros
BACKGROUND: Differences in plasma and whole blood expression microRNAs (miRNAs) in patients with an acute coronary syndrome (ACS) have been determined in both in vitro and in vivo studies. Although most circulating miRNAs are located in the cellular components of whole blood, little is known about the miRNA profiles of whole blood subcomponents, including plasma, platelets and leukocytes in patients with myocardial ischemia. METHODS: Thirteen patients with a ST-segment-elevation (STEMI) or non-ST-segment elevation (NSTEMI) myocardial infarction were identified in the University of Massachusetts Medical Center Emergency Department (ED) or cardiac catheterization laboratory between February and June of 2012. Whole blood …
The Embryonic Mir-35 Family Of Micrornas Promotes Multiple Aspects Of Fecundity In Caenorhabditis Elegans, Katherine Mcjunkin, Victor R. Ambros
The Embryonic Mir-35 Family Of Micrornas Promotes Multiple Aspects Of Fecundity In Caenorhabditis Elegans, Katherine Mcjunkin, Victor R. Ambros
Victor R. Ambros
MicroRNAs guide many aspects of development in all metazoan species. Frequently, microRNAs are expressed during a specific developmental stage to perform a temporally defined function. The C. elegans mir-35-42 microRNAs are expressed abundantly in oocytes and early embryos and are essential for embryonic development. Here, we show that these embryonic microRNAs surprisingly also function to control the number of progeny produced by adult hermaphrodites. Using a temperature-sensitive mir-35-42 family mutant (a deletion of the mir-35-41 cluster), we demonstrate three distinct defects in hermaphrodite fecundity. At permissive temperatures, a mild sperm defect partially reduces hermaphrodite fecundity. At restrictive temperatures, somatic gonad …
An Efficient And Sensitive Method For Preparing Cdna Libraries From Scarce Biological Samples, Catherine H. Sterling, Isana Veksler-Lublinsky, Victor R. Ambros
An Efficient And Sensitive Method For Preparing Cdna Libraries From Scarce Biological Samples, Catherine H. Sterling, Isana Veksler-Lublinsky, Victor R. Ambros
Victor R. Ambros
The preparation and high-throughput sequencing of cDNA libraries from samples of small RNA is a powerful tool to quantify known small RNAs (such as microRNAs) and to discover novel RNA species. Interest in identifying the small RNA repertoire present in tissues and in biofluids has grown substantially with the findings that small RNAs can serve as indicators of biological conditions and disease states. Here we describe a novel and straightforward method to clone cDNA libraries from small quantities of input RNA. This method permits the generation of cDNA libraries from sub-picogram quantities of RNA robustly, efficiently and reproducibly. We demonstrate …
Immunopurification Of Ago1 Mirnps Selects For A Distinct Class Of Microrna Targets, Xin Hong, Molly Hammell, Victor Ambros, Stephen Cohen
Immunopurification Of Ago1 Mirnps Selects For A Distinct Class Of Microrna Targets, Xin Hong, Molly Hammell, Victor Ambros, Stephen Cohen
Victor R. Ambros
microRNAs comprise a few percent of animal genes and have been recognized as important regulators of a diverse range of biological processes. Understanding the biological functions of miRNAs requires effective means to identify their targets. Combined efforts from computational prediction, miRNA over-expression or depletion, and biochemical purification have identified thousands of potential miRNA-target pairs in cells and organisms. Complementarity to the miRNA seed sequence appears to be a common principle in target recognition. Other features, including miRNA-target duplex stability, binding site accessibility, and local UTR structure might affect target recognition. Yet computational approaches using such contextual features have yielded largely …
Drosophila Let-7 Microrna Is Required For Remodeling Of The Neuromusculature During Metamorphosis, Nicholas S. Sokol, Peizhang Xu, Yuh-Nung Jan, Victor R. Ambros
Drosophila Let-7 Microrna Is Required For Remodeling Of The Neuromusculature During Metamorphosis, Nicholas S. Sokol, Peizhang Xu, Yuh-Nung Jan, Victor R. Ambros
Victor R. Ambros
The Drosophila let-7-Complex (let-7-C) is a polycistronic locus encoding three ancient microRNAs: let-7, miR-100, and fly lin-4 (miR-125). We find that the let-7-C locus is principally expressed in the pupal and adult neuromusculature. let-7-C knockout flies appear normal externally but display defects in adult behaviors (e.g., flight, motility, and fertility) as well as clear juvenile features in their neuromusculature. We find that the function of let-7-C to ensure the appropriate remodeling of the abdominal neuromusculature during the larval-to-adult transition is carried out predominantly by let-7 alone. This heterochronic role of let-7 is likely just one of the ways in which …
Effect Of Life History On Microrna Expression During C. Elegans Development, Xantha Karp, Molly Hammell, Maria C. Ow, Victor R. Ambros
Effect Of Life History On Microrna Expression During C. Elegans Development, Xantha Karp, Molly Hammell, Maria C. Ow, Victor R. Ambros
Victor R. Ambros
Animals have evolved mechanisms to ensure the robustness of developmental outcomes to changing environments. MicroRNA expression may contribute to developmental robustness because microRNAs are key post-transcriptional regulators of developmental gene expression and can affect the expression of multiple target genes. Caenorhabditis elegans provides an excellent model to study developmental responses to environmental conditions. In favorable environments, C. elegans larvae develop rapidly and continuously through four larval stages. In contrast, in unfavorable conditions, larval development may be interrupted at either of two diapause stages: The L1 diapause occurs when embryos hatch in the absence of food, and the dauer diapause occurs …
Micrornas: Genetically Sensitized Worms Reveal New Secrets, Victor Ambros
Micrornas: Genetically Sensitized Worms Reveal New Secrets, Victor Ambros
Victor R. Ambros
Why do many microRNA gene mutants display no evident phenotype? Multiply mutant worms that are selectively impaired in genetic regulatory network activities have been used to uncover previously unknown functions for numerous Caenorhabditis elegans microRNAs.
Prb/Cki Pathways At The Interface Of Cell Cycle And Development, Victor Ambros
Prb/Cki Pathways At The Interface Of Cell Cycle And Development, Victor Ambros
Victor R. Ambros
Comment on: The cyclin-dependent kinase inhibitors, cki-1 and cki-2, act in overlapping but distinct pathways to control cell-cycle quiescence during C. elegans development. Buck SH, et al. Cell Cycle 2009; 8:2613-20.
Purification And Properties Of A Hela Cell Enzyme Able To Remove The 5'-Terminal Protein From Poliovirus Rna, Victor Ambros, David Baltimore
Purification And Properties Of A Hela Cell Enzyme Able To Remove The 5'-Terminal Protein From Poliovirus Rna, Victor Ambros, David Baltimore
Victor R. Ambros
Using a rapid phenol extraction assay, an enzyme was purified from uninfected HeLa cells that can cleave the 5'-terminal protein (VPg) from poliovirus RNA. Both cytoplasmic and nuclear extracts had enzymes with similar behavior. A polypeptide of molecular weight 27,000 was the major one present in the purified preparation. Assuming that this protein is the enzyme, a very low turnover number was calculated for it. The purified enzyme would cleave the tyrosine-phosphate bond linking VPg to poliovirus RNA with minimal degradation of the RNA or of VPg. If the RNA was first treated with proteinase K to degrade VPg, leaving …
An Enzymatic Activity In Uninfected Cells That Cleaves The Linkage Between Poliovirion Rna And The 5' Terminal Protein, Victor Ambros, Ralf Pettersson, David Baltimore
An Enzymatic Activity In Uninfected Cells That Cleaves The Linkage Between Poliovirion Rna And The 5' Terminal Protein, Victor Ambros, Ralf Pettersson, David Baltimore
Victor R. Ambros
The 5' terminal protein (VPg) on poliovirion RNA can be removed by cell-free extracts from a variety of uninfected cells. This soluble enzymatic activity is found in both nuclear and cytoplasmic extracts of heLa cells and is activated by Mg++. The enzyme activity cleaves the tyrosine-phosphate bond that links the protein to the RNA. In a partially purified form it has insufficient nonspecific protease or nuclease activity to account for its action. The existence of this enzyme implies that poliovirus RNA is translated in cell-free extracts in a form that lacks the 5' terminal protein. The role of this enzyme …
Protein Is Linked To The 5' End Of Poliovirus Rna By A Phosphodiester Linkage To Tyrosine, Victor Ambros, David Baltimore
Protein Is Linked To The 5' End Of Poliovirus Rna By A Phosphodiester Linkage To Tyrosine, Victor Ambros, David Baltimore
Victor R. Ambros
Purification and partial characterization of the poliovirus RNA-linked protein (VPg) are described. VPg has been freed from the RNA by ribonuclease digestion and phenol extraction. Gel filtration chromatography of VPg-pUp (labeled with 32P) in 0.5% sodium dodecyl sulfate or 6 M guanidine HCl indicates that it has a molecular weight of about 12,000. VPg is bound to the 5' end of poliovirion RNA by a phosphodiester bond between a tyrosine residue in the VPg molecule and the 5'-terminal uridine. After acid hydrolysis of [3H]tyrosine-labeled VPg-pU, free tyrosine can be released by venom phosphodiesterase. Acid hydrolysis of VPg-p labeled with either …
Identification Of A Protein Linked To Nascent Poliovirus Rna And To The Polyuridylic Acid Of Negative-Strand Rna, Ralf F. Pettersson, Victor R. Ambros, David Baltimore
Identification Of A Protein Linked To Nascent Poliovirus Rna And To The Polyuridylic Acid Of Negative-Strand Rna, Ralf F. Pettersson, Victor R. Ambros, David Baltimore
Victor R. Ambros
A protein similar to that previously demonstrated on poliovirus RNA and replicative intermediate RNA (VPg) was found on all sizes of nascent viral RNA molecules and on the polyuridylic acid isolated from negative-strand RNA. 32P-labeled nascent chains were released from their template RNA and fractionated by exclusion chromatography on agarose. Fingerprint analysis using two-dimensional polyacrylamide gels of RNase T1 oligonucleotides derived from nascent chains of different lengths showed that a size fractionation of nascent chains was achieved. VPg was recovered from nascent chains varying in length from 7,500 nucleotides (full-sized RNA) to about 500 nucleotides. No other type of 5' …
Separation Of Quantitation Of Intracellular Forms Of Poliovirus Rna By Agarose Gel Electrophoresis, Martinez Hewlett, Shmuel Rozenblatt, Victor Ambros, David Baltimore
Separation Of Quantitation Of Intracellular Forms Of Poliovirus Rna By Agarose Gel Electrophoresis, Martinez Hewlett, Shmuel Rozenblatt, Victor Ambros, David Baltimore
Victor R. Ambros
Intracellular poliovirus-specific RNA species can be measured directly by electrophoresis of total cytoplasmic nucleic acids through 1% agarose gels, resulting in the separation of single- and double-stranded forms of poliovirus RNA from each other and from HeLa cell 28S ribosomal RNA. Single-stranded RNA molecules differing by only 15% in length are resolved in this gel system. RNA species can be visualized as fluorescen bands appearing after staining of the gels with ethidium bromide and observation under ultraviolet illumination. The total amount of RNA can be determined by densitometric quantitation of the fluorescent response. In this way, the amount of poliovirus-specific …
Covalent Linkage Of A Protein To A Defined Nucleotide Sequence At The 5'-Terminus Of Virion And Replicative Intermediate Rnas Of Poliovirus, James B. Flanegan, Ralf F. Pettersson, Victor R. Ambros, Martinez J. Hewlett, David Baltimore
Covalent Linkage Of A Protein To A Defined Nucleotide Sequence At The 5'-Terminus Of Virion And Replicative Intermediate Rnas Of Poliovirus, James B. Flanegan, Ralf F. Pettersson, Victor R. Ambros, Martinez J. Hewlett, David Baltimore
Victor R. Ambros
The 5'-terminus of poliovirus polyribosomal RNA is pUp. A candidate for the 5'-terminus of poliovirion RNA was recovered as a compound migrating toward the cathode when 32P-labeled virion RNA was completely digested with ribonucleases T1, T2 and A and analyzed by paper ionophoresis at pH 3.5. Treatment with proteinase K reversed its direction of migration, indicating the presence of protein. Treatment with venom phosphodiesterase liberated all of the radioactivity as pUp, suggesting that poliovirion RNA has a protein-pUp 5'-terminus. Treatment of virion RNA with T1 ribonuclease alone generated a proteinase K-sensitive oligoribonucleotide. Analysis of the oligoribonucleotide using ribonucleases A and …