Showing papers on "Intron published in 1974"
TL;DR: A very low level of methylation is detected in heterogeneous nuclear RNA, suggesting that methylation, like polyadenylation, may constitute a post-transcriptional modification of messenger RNA precursor in eucaryotic cells.
352 citations
TL;DR: The product, pCmpUp, previously reported by Choi & Busch (1970) as being the 5′ end-group of rat hepatoma 28 S, 32 S and 45 S RNA, is not present in HeLa cell 28 S RNA or its precursors.
149 citations
TL;DR: Observations suggest that the sequence complementarity that gives rise to this highly conserved secondary structure pattern in L-cell rRNA may have some functional importance.
112 citations
TL;DR: The existence of three stable forms of the 5.8-S ribosomal RNA species in Saccharomyces cerevisiae has been demonstrated and the remainders of the sequence of all three forms appear to be identical.
Abstract: The existence of three stable forms of the 5.8-S ribosomal RNA species in Saccharomyces cerevisiae has been demonstrated. The major form constitutes approximately 90% of the total 5.8-S RNA and the two minor forms each constitute approximately 5%. The nucleotide sequence of the major form begins pA-A-A-Cp. The sequences of the minor forms begin pU-A-U-U-A-A-A-A-A Cp and pA-U-A-U-U-A-A-A-A-A-Cp. The remainders of the sequence of all three forms appear to be identical.
98 citations
TL;DR: Evidence indicates that viral polypeptide abundances are specified at the transcriptional level and the requirement for capsid proteins in RNA replication suggests that these proteins are positive control elements for replication of paramyxovirus RNA.
Abstract: This review evaluates possible mechanisms which regulate paramyxovirus protein and RNA syntheses. Evidence indicates that viral polypeptide abundances are specified at the transcriptional level. RNA replication and transcription are competing processes utilizing an encapsidated single-stranded RNA template. The requirement for capsid proteins in RNA replication suggests that these proteins are positive control elements for replication of paramyxovirus RNA.
94 citations
88 citations
TL;DR: The major transcripts read by T7 RNA polymerase from T3-T7 hybrid phage DNAs vary, depending on which regions of the T7 chromosome are present, and this provides an alternative method of mapping the strong T7 promotor sites on the T6 chromosome.
Abstract: Transcription of T7 DNA by T7 RNA polymerase in vitro gives rise to six major size classes of RNAs comprising seven major T7 RNA species. These RNAs are all read from the r-strand of T7 DNA and are not derived from the early (leftmost on the conventional genetic map) region of the molecule. When artifically shortened T7 DNA templates are transcribed, four (I, II, IIIb, and VI) of the seven species are found to be truncated or deleted. This indicates that all are terminated near the right end of the T7 DNA molecule, probably at a common termination site near 98.5%. (Map positions are all given in terms of percentage of total length measured from the left end of the molecule.) Since the approximate lengths of the transcripts are known, the promotor sites for T7 RNA species I, II, IIIb, and VI are tentatively mapped at 56, 64, 83, and 97% on the T7 chromosome. Only a single major T3 RNA is transcribed by T7 RNA polymerase; analysis of transcripts directed by shortened T3 DNA templates indicates it is analogous to T7 RNA species IIIb. Hence the promotor and terminator sites for T3 species IIIb are tentatively mapped at 83 and 98.5%, respectively, on the T3 chromosome. The major transcripts read by T7 RNA polymerase from T3-T7 hybrid phage DNAs vary, depending on which regions of the T7 chromosome are present. This provides an alternative method of mapping the strong T7 promotor sites on the T7 chromosome.
66 citations
TL;DR: In situ hybridisation is used to locate a major 5S RNA locus near the end of the long arm of chromosome 1 of man and suggests a mechanism for positioning the 5S genes near nucleoli at interphase.
Abstract: WE have used in situ hybridisation to locate a major 5S RNA locus near the end of the long arm of chromosome 1 of man. This information represents a step towards the understanding of the synthesis, assembly and regulation of ribosomes. The 5S RNA molecule is associated with the larger ribosomal particle in both higher and lower organisms and is required for ribosome function. Ribosomal RNA—18S and 28S—is synthesised at the nucleolar organiser regions on the chromosomes of the D and G groups1. Genes coding for 5S RNA have been located in Drosophila2, Xenopus3 and several other organisms4, and our data now confirm preliminary reports5,6 that placed the 5S genes on chromosome 1 of man. We also suggest a mechanism for positioning the 5S genes near nucleoli at interphase.
61 citations
TL;DR: Findings serve to localize the sites at which proteins incapable of independent interaction with 16 S RNA are fixed during the early stages of 30 S subunit assembly.
43 citations
TL;DR: The nucleotide sequence of a transfer RNA precursor molecule coded by bacteriophage T4 has been determined in this paper, which is a single polynucleotide chain which contains two transfer RNA species that are destined to recognize serine and proline.
Abstract: The nucleotide sequence of a transfer RNA precursor molecule coded by bacteriophage T4 has been determined. The molecule is a single polynucleotide chain which contains two transfer RNA species that are destined to recognize serine and proline. The 3′ -CCAOH termini of both mature transfer RNA species are absent in the precursor molecule; these termini must therefore be added enzymatically at a subsequent stage of maturation. Nucleotide residues unique to the precursor are located at both ends of the molecule and between the two transfer RNA sequences.
43 citations
TL;DR: The results indicate that the transcription of reovirus double-stranded RNA strats from the 3' end complementary to the G(*)pCp-terminal, resulting in the synthesis of single-Stranded mRNA carrying the same 5' sequence as the G (*)p Cp-chain.
Abstract: The 5′-terminal nucleotide sequences of human reovirus double-stranded RNA were determined after labeling the RNA with [32P]phosphate by polynucleotide kinase. The 5′ terminal were labeled to only a limited extent prior to sequential oxidation, β-elimination, and phosphomonoesterase treatment, indicating that the terminal phosphates were in a modified, blocked configuration. Each genome segment, after removing the blocking group, contained the same two 5′-terminal sequences: GpApUp in one chain and G*pCp in the other. G*p is a derivative of guanylic acid, probably 2′-O-methyl-Gp, which renders the 5′-terminal sequence resistant to hydrolysis by alkali. The results indicate that the transcription of reovirus double-stranded RNA strats from the 3′ end complementary to the G*pCp-terminal, resulting in the synthesis of single-stranded mRNA carrying the same 5′ sequence as the G*pCp-chain. The presence of a modified nucleotide at the 5′ terminus of the strand complementary to the mRNA template is a feature common to another double-stranded RNA virus, cytoplasmic polyhedrosis virus.
TL;DR: Complete transcripts of the genome of vesicular stomatitis virus Indiana strain have been used to hybridize to virion RNA to determine if there is RNA sequence homology among these viruses.
Abstract: Complete transcripts of the genome of vesicular stomatitis virus Indiana strain have been used to hybridize to virion RNA to determine if there is RNA sequence homology among these viruses. Cellular RNA from cells infected by each of these viruses has also been used for hybridization with the homologous or heterologous virion RNA. The results indicate that there is little exact sequence homology among these viruses.
TL;DR: The nucleotide sequence of 180 residues of an RNA transcript of DNA of simian virus 40 has been deduced and this sequence adjoins a preferred initiation site for E. coli RNA polymerase.
Abstract: The nucleotide sequence of 180 residues of an RNA transcript of DNA of simian virus 40 has been deduced. This sequence adjoins a preferred initiation site for E. coli RNA polymerase. Comparison of this sequence with that of complementary RNA of simian virus 40 from infected cells has shown that this site also adjoins the apparent 3′ terminus of some of the cytoplasmic complementary RNA of simian virus 40.
TL;DR: Molecular hybridisation of the cRNA synthesised by A and B enzymes from DNA enriched with ribosomal cistrons and main-band DNA demonstrated that only transcripts of rDNA by the form A RNA polymerase were competed out by unlabelled 18-S and 28-S Xenopus Ribosomal RNAs.
Abstract: 1
The activities of DNA-dependent RNA polymerases A and B purified from ovaries of Xenopus laevis were examined on various templates.
2
When bulk Xenopus DNA was centrifuged in caesium chloride gradients the ratio of incorporation of UMP and GMP into RNA by the two enzymes different in the region where the ribosomal cistrons banded when the fractionated DNAs were used as templates. The A enzyme selectively synthesised G-rich RNA under conditions where the enzyme :rDNA ratio was high, whereas no conditions were found under which the B enzyme would synthesise G-rich RNA.
3
Molecular hybridisation of the cRNA synthesised by A and B enzymes from DNA enriched with ribosomal cistrons and main-band DNA demonstrated that only transcripts of rDNA by the form A RNA polymerase were competed out by unlabelled 18-S and 28-S Xenopus ribosomal RNAs.
4
Both forms A and B RNA polymerases were capable of forming rifamycin AF/0-13 resistant complexes on either main-band or ribosomal DNA. However, whereas the amount of resistance by the B enzyme was similar on both templates, RNA polymerase A became much more resistant on rDNA than on main-band DNA.
5
Sensitivity to actinomycin D and the exotoxin from Bacillus thuringiensis, both of which inhibit ribosomal RNA synthesis preferentially in vivo, was apparently independent of the type of template used in these experiments.
TL;DR: Only two sites in 5 S RNA react with Kethoxal in 50 S ribosomal subunits and nucleotide sequences which have been suggested as possible binding sites for the T-ψ-C-G loop of tRNA are not accessible.
TL;DR: This chapter presents standard procedures for isolation of undegraded RNA from various tissues and cell fractions and suggests that high temperature not only increases the rate of RNA extraction, but also suppresses the release of DNA into the aqueous phase, resulting in a lower contamination of DNA.
Abstract: Publisher Summary This chapter presents standard procedures for isolation of undegraded RNA from various tissues and cell fractions. In animal cells, ribosomal particles contain RNA species with sedimentation coefficients of 28 S, 18 S, 7 S, and 5 S. The large ribosomal subunit contains one molecule of 28 S, 7 S, and 5 S RNA. 7 S RNA is known to be hydrogen-bonded with 28 S RNA, whereas 5 S RNA appears to exist as a mini subunit in association with a protein. The small ribosomal subunit contains one 18 S RNA molecule. Isolation of these RNAs can be accomplished either from whole cells, post mitochondrial supernatant, ribosomes, or ribosomal subunits. Theoretically, the purest ribosomal RNA should be obtainable from ribosomal subunits. High temperature not only increases the rate of RNA extraction, but also suppresses the release of DNA into the aqueous phase, resulting in a lower contamination of DNA. At least 55°C is required for efficient extraction of nuclear RNA. Higher temperatures result in a higher rate of extraction of tightly bound nuclear RNA.
TL;DR: The sequence of Chlorella cytoplasmic 5 S RNA has been determined by fingerprinting techniques and the conformation of the molecule in solution is quite different from that of other sequenced 5 S RNAs.
TL;DR: Several methylated components in Drosophila rRNA also occur in rRNA from HeLa cells and yeast, which suggests that certain features of rRNA structure involving methylated nucleotides may be highly conserved in eukaryotic evolution.
TL;DR: A unique sequence (5') A U U G C p o l y A (3') was thus deduced for the globin mRNA and this sequence may represent a termination signal for transcription and a recognition site for the addition of poly A.
TL;DR: Both possibilities suggest that the change in the protein S4 is not only responsible for the thermosensitive character of ribosomal assembly in this mutant, but also causes an alteration in the trimming site, affecting its recognition by the enzyme involved in the maturation.
Abstract: The precursor and mature 16S ribosomal RNAs from a novel thermosensitive ribosomal assembly defective mutant of E. coli, in which genetic evidence suggests that the ribosomal protein S4 is altered, have been isolated and characterised by finger-printing methods. The precursor 16S RNA, which is accumulated at 42 degrees , appears to be identical with that present in wild-type strains, and with that previously described by other workers. However, the mature 16S RNA, which is contained in apparently normal functional 30S ribosomal particles synthesised at the growth-permissive temperature of 30 degrees , is incompletely trimmed and has either one or two additional nucleotides at its 5'-terminus. This might be due either to an accumulation of two late intermediates in the maturation process, or to mis-trimming of the RNA. Both possibilities suggest that the change in the protein S4 is not only responsible for the thermosensitive character of ribosomal assembly in this mutant, but also causes an alteration in the trimming site, affecting its recognition by the enzyme involved in the maturation.
TL;DR: It is hoped that the study of the structure of normal human globin mRNA compared to that of mRNA obtained from various disease states may directly reveal the precise, molecular basis of certain disorders of human hemoglobin synthesis.
Abstract: The study of the nucleotide sequence of human globin messenger RNA (mRNA) has been undertaken to examine a number of questions relating to the control of globin synthesis in man. These questions concern the universality and degeneracy of the genetic code in man; the authenticity and purity of the putative 10s globin mRNA; and the primary structure of untranslated portions of globin mRNA, which may be important for mRNA stability and the control of mRNA translation, or which may be the copy of DNA sequences, adjacent to the structural gene and possibly involved in the control of mRNA synthesis. It is hoped that the study of the structure of normal human globin mRNA compared to that of mRNA obtained from various disease states may directly reveal the precise, molecular basis of certain disorders of human hemoglobin synthesis. Most techniques used in RNA sequencing rely on radioautography of :InP-
TL;DR: The nucleotide sequence of the 5S ribosomal RNA of somatic cells of the chicken (Gallus gallus) differs from that of other vertebrates thus far examined and alterations include two nucleotide deletions and two additions.
Abstract: The nucleotide sequence of the 5S ribosomal RNA of somatic cells of the chicken (Gallus gallus) differs from that of other vertebrates thus far examined. Besides base substitutions, alterations include two nucleotide deletions and two additions.
TL;DR: The 3′-terminal T1 oligonucleotide of E. coli 16S ribosomal RNA has been sequenced, using U2 and silkworm nucleases, and was found to be A-U-C-A-C
Abstract: The 3′-terminal T1 oligonucleotide of E. coli 16S ribosomal RNA has been sequenced, using U2 and silkworm nucleases, and was found to be A-U-C-A-C-C-U-C-C-U-U-AOH. This result is discussed in view of previously reported conflicting sequences and with respect to suggested functional roles for this region of 16S RNA.
TL;DR: This article reports the existence, in a Drosophila cell line, of another small RNA molecule hydrogenbonded to 26 S RNA, which appears to be derived from 26 SRNA or its nearest precursor during one of the last steps of rRNA processing.
TL;DR: Double-stranded RNA fails to inhibit the formation of translation initiation complexes on R17 bacteriophage RNA, overall synthesis of R17 proteins, or the ability of bacterial initiation factor IF-3 to prevent the association of 30S and 50S ribosomal subunits into single ribosomes.
TL;DR: When using phiX174 RFI DNA as a template, invitro, E. coli RNA polymerase synthesizes four major purine triphosphate-containing 5' end sequences.
Abstract: When using oX17U RFI DNA as a template, in vitro, E. coli RNA polymerase synthesizes four major purine triphosphate-containing 5' end sequences. RNase A digests of 32P labeled RNA were further digested with spleen exonuclease to remove the bulk of the oligonucleotides with 5' hydroxyls and then chromatographed on DEAE cellulose to resolve the remaining 5' terminal oligonucleotides. By application of standard separation and sequence techniques, the major 5' end sequences were shown to be: pppApUp(Cp), pppApApApUp(Cp), pppApApApApUp(Cp), and pppGpApUp(Gp).
TL;DR: It is shown that one of the mutants has conserved a large fraction of the region of mitochondrial DNA coding for mitochondrial ribosomal RNA, and this region was transcribed into an RNA which was similar or identical to intact 23S ribosome RNA.