The Experts below are selected from a list of 4188 Experts worldwide ranked by ideXlab platform
Elizabeth Dicksont - One of the best experts on this subject based on the ideXlab platform.
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(RNA processing/Heterogeneous Nuclear RNA/RNA precursors)
2016Co-Authors: Stefano Ferrari, Hugh D. Robertson, Elizabeth DicksontAbstract:Subcellular fractionation of HeLa cells was carried out under gentle conditions to isolate enzymes that cleave RNA precursors in a specific manner. Four separate ac- tivities-cleavage of HeLa cell Heterogeneous Nuclear RNA, the HeLa cell 45S rRNA precursor, RNA-DNA hybrids (RNAse H), and the Escherichia coli tRNATYr precursor (RNAse P)-were revealed by these studies. The specificity and limited nature of these cleavages suggest that they are due to eukaryotic RNA- processing enzymes. The virtual absence of random nucleases from these enzymes was demonstrated by their inability to cleave the 8000-base early mRNA precursor of bacteriophage 17, E. coli 30S rRNA precursor, or HeLa cytoplasmic poly(A- containing RNA.
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RNA processing Heterogeneous Nuclear RNA RNA precursors
2016Co-Authors: Stefano Ferrari, Hugh D. Robertson, Elizabeth DicksontAbstract:Subcellular fractionation of HeLa cells was carried out under gentle conditions to isolate enzymes that cleave RNA precursors in a specific manner. Four separate ac- tivities-cleavage of HeLa cell Heterogeneous Nuclear RNA, the HeLa cell 45S rRNA precursor, RNA-DNA hybrids (RNAse H), and the Escherichia coli tRNATYr precursor (RNAse P)-were revealed by these studies. The specificity and limited nature of these cleavages suggest that they are due to eukaryotic RNA- processing enzymes. The virtual absence of random nucleases from these enzymes was demonstrated by their inability to cleave the 8000-base early mRNA precursor of bacteriophage 17, E. coli 30S rRNA precursor, or HeLa cytoplasmic poly(A- containing RNA.
Stefano Ferrari - One of the best experts on this subject based on the ideXlab platform.
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(RNA processing/Heterogeneous Nuclear RNA/RNA precursors)
2016Co-Authors: Stefano Ferrari, Hugh D. Robertson, Elizabeth DicksontAbstract:Subcellular fractionation of HeLa cells was carried out under gentle conditions to isolate enzymes that cleave RNA precursors in a specific manner. Four separate ac- tivities-cleavage of HeLa cell Heterogeneous Nuclear RNA, the HeLa cell 45S rRNA precursor, RNA-DNA hybrids (RNAse H), and the Escherichia coli tRNATYr precursor (RNAse P)-were revealed by these studies. The specificity and limited nature of these cleavages suggest that they are due to eukaryotic RNA- processing enzymes. The virtual absence of random nucleases from these enzymes was demonstrated by their inability to cleave the 8000-base early mRNA precursor of bacteriophage 17, E. coli 30S rRNA precursor, or HeLa cytoplasmic poly(A- containing RNA.
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RNA processing Heterogeneous Nuclear RNA RNA precursors
2016Co-Authors: Stefano Ferrari, Hugh D. Robertson, Elizabeth DicksontAbstract:Subcellular fractionation of HeLa cells was carried out under gentle conditions to isolate enzymes that cleave RNA precursors in a specific manner. Four separate ac- tivities-cleavage of HeLa cell Heterogeneous Nuclear RNA, the HeLa cell 45S rRNA precursor, RNA-DNA hybrids (RNAse H), and the Escherichia coli tRNATYr precursor (RNAse P)-were revealed by these studies. The specificity and limited nature of these cleavages suggest that they are due to eukaryotic RNA- processing enzymes. The virtual absence of random nucleases from these enzymes was demonstrated by their inability to cleave the 8000-base early mRNA precursor of bacteriophage 17, E. coli 30S rRNA precursor, or HeLa cytoplasmic poly(A- containing RNA.
Hugh D. Robertson - One of the best experts on this subject based on the ideXlab platform.
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(RNA processing/Heterogeneous Nuclear RNA/RNA precursors)
2016Co-Authors: Stefano Ferrari, Hugh D. Robertson, Elizabeth DicksontAbstract:Subcellular fractionation of HeLa cells was carried out under gentle conditions to isolate enzymes that cleave RNA precursors in a specific manner. Four separate ac- tivities-cleavage of HeLa cell Heterogeneous Nuclear RNA, the HeLa cell 45S rRNA precursor, RNA-DNA hybrids (RNAse H), and the Escherichia coli tRNATYr precursor (RNAse P)-were revealed by these studies. The specificity and limited nature of these cleavages suggest that they are due to eukaryotic RNA- processing enzymes. The virtual absence of random nucleases from these enzymes was demonstrated by their inability to cleave the 8000-base early mRNA precursor of bacteriophage 17, E. coli 30S rRNA precursor, or HeLa cytoplasmic poly(A- containing RNA.
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RNA processing Heterogeneous Nuclear RNA RNA precursors
2016Co-Authors: Stefano Ferrari, Hugh D. Robertson, Elizabeth DicksontAbstract:Subcellular fractionation of HeLa cells was carried out under gentle conditions to isolate enzymes that cleave RNA precursors in a specific manner. Four separate ac- tivities-cleavage of HeLa cell Heterogeneous Nuclear RNA, the HeLa cell 45S rRNA precursor, RNA-DNA hybrids (RNAse H), and the Escherichia coli tRNATYr precursor (RNAse P)-were revealed by these studies. The specificity and limited nature of these cleavages suggest that they are due to eukaryotic RNA- processing enzymes. The virtual absence of random nucleases from these enzymes was demonstrated by their inability to cleave the 8000-base early mRNA precursor of bacteriophage 17, E. coli 30S rRNA precursor, or HeLa cytoplasmic poly(A- containing RNA.
Thoru Pederson - One of the best experts on this subject based on the ideXlab platform.
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Structure of Nuclear ribonucleopro RNA is complexed with a major ses (mouse erythroleukemia cells/RNA-protein crosslinking/topography
2016Co-Authors: Ioannis V. Economidis, Thoru PedersonAbstract:Mouse erythroleukemia cells were pulse-labeled with (3H)uridine and irradiated with 254-nm light to produce cova- lent crosslinks between RNA and proteins in close proximity to one another in vivo. Nuclear ribonucleoprotein particles containing Heterogeneous Nuclear RNA were isolated and digested with nu- cleases, and the resulting proteins were subjected to gel electro- phoresis. Proteins carrying covalently crosslinked (3H)uridine nu- cleotides were identified by fluorography. The results demonstrate that Heterogeneous Nuclear RNA is complexed in vivo with a set of six major proteins having molecular weights between 32,500 and 41,500. Analysis of chromatin fractions indicates that nascent het- erogeneous Nuclear RNA chains assemble with these six proteins as a very early post-transcriptional event. These data, and other results (Nevins, J. R. & Darnell, J. E. (1981) Cell 15,1477-1493), lead us to propose the usual order of post-transcriptional events to be: Heterogeneous Nuclear RNA-ribonucleoprotein particle as- sembly -- poly(A) addition -> splicing.
David W. Kopp - One of the best experts on this subject based on the ideXlab platform.
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Differential Metabolism of Large and Small Poly(A) Sequences in the Heterogeneous Nuclear RNA of HeLa Cells (transcriptional synthesis/messenger RNA/3'-deoxyadenosine/actinomycin D)
2017Co-Authors: Hiroshi Nakazato, Mary Edmonds, David W. KoppAbstract:The Heterogeneous RNA of the HeLa cell nucleus contains short inteRNAl poly(A) sequences which, in contrast to the longer poly(A) sequences at the 3' ends, are not found in messenger RNA of the cytoplasm. A dis- tinct origin for each of these homologous sequences is evi- dent'when the effects of actinomycin D and 3'-deoxyadeno- sine on their biosynthesis are compared. The shorter poly(A) appears to be transcribed, while the longer one does not. A kinetic analysis of the metabolism of each type of poly(A) sequence within different size classes of HnRNA after treatment of the cells with 3'-deoxyadenosine reveals distinctive distribution and metabolism of these sequences and also provides insight into mechanisms proposed for the generation of messenger RNA from these large RNA molecules in the nucleus. We have recently detected a short poly(A) sequence in the Heterogeneous Nuclear RNA (HnRNA) of HeLa cells (1) which, in contrast to the large poly(A) sequence described earlier (2), is not found in the cytoplasm nor at the 3'-end of HnRNA (1). The existence of two classes of poly(A) se- quences in HnRNA, only one of which is at the 3'-terminus, which are readily separated on the basis of length presented an experimental opportunity for comparing the mechanisms of their biosynthesis. We wish to report the results of two types of experiments which clearly reveal distinct mechanisms for the biosynthesis of the two poly(A) species. First, comparison of the differen- tial effects of actinomycin D and 3'-deoxyadenosine on the biosynthesis of the two sequences clearly points to a tran- scriptional synthesis of small poly(A) which is not evident for the larger poly(A) sequence. In a second set of experiments, the distribution of large and small poly(A) sequences in dif- ferent size classes of HnRNA has been examined. Changes in the distribution of label in the two sequences within each size class after the addition of 3'-deoxyadenosine again emphasizes the unique metabolism of each type of sequence. The relevance of these data to models currently proposed to account for the generation of messenger RNA by mecha- nisms involving processing of large HnRNA molecules will be discussed.