2 edition of Studies on DNA sequences directing ribosomal transcription in Xenopus laevis found in the catalog.
Studies on DNA sequences directing ribosomal transcription in Xenopus laevis
Duncan Richard Smith
by Portsmouth Polytechnic, Dept. of Biological Sciences in Portsmouth
Written in English
|Statement||by Duncan Richard Smith.|
Abstract. With the aid of a novel poly-dA tailing-partial restriction technique and Sl-protection mapping, the 5′ terminal coding sequence for the 4OS precursor ribosomal RNA of Xenopus laevis has been exactly identified. Since the promoter sequence for the 4OS RNA should lie close to its 5′ terminal coding sequence, we are able to conclude that the “Bam-Island” sequence reduplication Cited by: In this study, we have located the sites of transcription initiation and termination on a cloned fragment of ribosomal DNA from X. laevis, and have sequenced the surrounding nucleotides. As reported previously (Reeder, Sollner-Webb and Wahn, ), about 25% of the 40S rRNA precursor molecules isolated from oocytes have polyphosphate 5' termini Cited by:
Sequence organization of the spacer DNA in a ribosomal gene unit of Xenopus laevis. Boseley P, Moss T, Mächler M, Portmann R, Birnstiel M. A detailed restriction map was constructed for a cloned Xenopus laevis rDNA fragment containing the nontranscribed spacer (NTS) and external transcribed spacer (ETS) together with a portion of both the 18S and 28S rRNA by: However, in oöcytes from a wide variety of animals, this nucleolar DNA is selectively amplified and accumulated in the nucleus free of the chromosomes (Gall, ). In Xenopus laevis, the best studied example, almost three-quarters of the nuclear DNA in a diplotene oöcyte codes exclusively for ribosomal RNA (Brown and Dawid, ). The extra Cited by: 8.
Cellular regulation of ribosomal DNA transcription: Both rat and Xenopus UBF1 stimulate rDNA transcription in 3T3 fibroblasts, Nucleic Acids Research, , pp. , 27/4, DOI: /nar/Cited by: GTC-3 ′ to amplify sequences – to +60 of the Xenopus laevis ribosomal promoter (26). Construction of UBF expression constructs A number of full-length and mutant rat and Xenopus UBF expression constructs were used in this study (Fig. 1B). pCMV-rUBF1 was generated by PCR from the rat UBF1 cDNA (27)Cited by:
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The DNA sequences required for efficient initiation of transcription of the Xenopus transcription factor IIIA (TFIIIA) gene were determined by microinjecting a series of deletion and linker substitution mutants into Xenopus oocyte by: Studies on DNA sequences directing ribosomal transcription in Xenopus laevis Author: Smith, D.
ISNI: Awarding Body: Portsmouth Polytechnic Current Institution: University of Portsmouth Date of Award: Availability of Full Text. Transcription of a cloned Xenopus laevis ribosomal DNA (rDNA) fragment, microinjected into Xenopus oocytes, is initiated at the in vivo 40S pre-ribosomal RNA (pre-rRNA) site (±2 bp) by RNA polymerase I.
An X. laevis RNA polymerase I promoter has been mapped by studying the transcription of in vitro rDNA mutants in the oocyte by: The ribosomal DNA spacer in Xenopus laevis was shown in previous studies to be involved in regulating the expression of the ribosomal genes.
Here transcription enhancement by this spacer has been studied in some detail, to fully identify the sequences involved and to determine their relative importance in this by: These ends hybridize specifically to a bp fragment of ribosomal DNA. The nucleotides encoding the 5′ end of the 40S RNA were located more precisely by two methods.
The nucleotide sequence of the initiation and termination sites for ribosomal rna transcription in x. laevis: CellCited by: DNA CLONING and the direct visualisation of chromatin transcription by electron microscopy provide useful details of the structure and function of genes, but the value of these techniques would be.
Abstract. In contrast to somatic cells, Xenopus oocytes accumulate large numbers of ribosomes for their subsequent use in early embryogenesis (Davidson, ).
To accommodate the need for ribosomal RNAs, the genes encoding the large ribosomal RNAs (i.e., 18 S, 28 S, and S rRNA) are amplified in the oocyte to yield about 2 × 10 6 extrachromosomal copies per nucleus (Brown and Weber, b Author: Angela Krämer.
The ribosomal DNA spacer in Xenopus laevis was shown in previous studies to be involved in regulating the expression of the ribosomal genes. Boseley P, Moss T, Mächler M, Portmann R, Birnstiel M. Sequence organization of the spacer DNA in a ribosomal gene unit of Xenopus laevis.
Cell. May; 17 (1)– Sollner-Webb B, Reeder RH. The nucleotide sequence of the initiation and termination sites for ribosomal RNA transcription in X. laevis. Cell. Oct; 18 (2)–Cited by: Volumenumber 2 FEBS LETTERS October PREPARATION OF COMPLEMENTARY DNA TO 5 S RIBOSOMAL RNA FROM XENOPUS LAEVIS Glenn E.
MORRIS and Trevor J. BEEBEE School of Biological Sciences, University of Sussex, Palmer, Cited by: 4. Abstract. Xenopus laevis is an important reference model organism used in many vertebrate studies.
Gene mapping in X. laevis, in comparison to other reference organisms, is in its early studies have been conducted to localize DNA sequences on X. laevis chromosomes. Primed in situ labeling (PRINS) is a recently developed innovative tool that has been used to locate specific DNA Cited by: 4.
Location of the genes for 5S ribosomal RNA in Xenopus laevis. Abstract. In situ hybridization of 5S RNA and cRNA transcribed in vitro from Xenopus laevis 5S DNA shows that 5S DNA is localized at or near the telomere region of the long arm of many, if not all, of the X.
laevis by: ribosomal gene transcription in Xenopus laevis Paul Labhart I and Ronald H. Reeder Fred Hutchinson Cancer Research Center, Division of Basic Sciences, Seattle, Washington USA Two sites, T2 and T3, in the ribosomal gene spacer of Xenopus laevis both direct RNA 3'-end formation 15 bp upstream of the conserved box sequence GACTTGC.
Rare individuals of Xenopus laevis exhibit frequent initiation of transcription in the spacers of oocyte ribosomal DNA (rDNA). Using electron microscopy we have characterized spacer transcription in such an individual and have confirmed that the sites of transcription initiation correspond to the imperfectly duplicated promoters ("Bam islands") present in the X.
laevis rDNA by: ► TFIIIA functions as specific transcription factor for 5S rRNA genes ► TFIIIA zinc-fingers bind both 5S rDNA and the 5S rRNA gene product with high affinity. ► Sequence comparison suggests co-evolution of TFIIIA protein and 5S rRNA genes.
► TFIIIA availability is highly regulated to ensure cell-specific amounts of 5S by: Mapping of a Sequence Essential for the Nuclear Transport of the Xenopus Ribosomal Transcription Factor xUBF Using a Simple Coupled Translation-Transport and Acid Extraction Approach May DNA.
The Xenopus egg extract has become the gold standard for in vitro studies of metazoan DNA replication.
We have used this system to study the mechanisms that ensure rapid and complete DNA. The X. laevis ribosomal DNA spacer contains duplicated RNA polymerase I ”spacer promoters“ and an array of repeated 60 81 bp promoter-related sequences. The latter have been shown to enhance transcription from a 40S preribosomal RNA promoter in we present evidence that at least one spacer promoter is also necessary for efficient by: A pentadeconucleotide, TGCCTCCCGAGTGCA, appeared twice within nucleotides upstream the putative initiation site.
No such characteristic sequences were found downstream this site. Little similarity was found in the upstream of the transcription initiation site between the mouse, Xenopus laevis and Saccharomyces cerevisiae by: The complete sequence of nucleotide Xenopus laevis mitochondrial genome has been determined.
A comparison of this amphibian mitochondrial genomic sequence with those of the mammalian mitochondrial genomes reveals a similar gene order and compact genomic by:. Localization of Repetitive DNA Sequences on in vitro Xenopus laevis Chromosomes by Primed in situ Labeling (PRINS) Article in Journal of Heredity 96(5) September with 19 Reads.In the first, electron microscopic R-loop mapping of human genomic DNA, enriched for ribosomal sequences, is used to analyze the distribution of length variants of rDNA repeat units from a single.
Abstract. The complete sequence of nucleotide Xenopus laevis mitochondrial genome has been determined. A comparison of this amphibian mitochondrial genomic sequence with those of the mammalian mitochondrial genomes reveals a similar gene order and compact genomic organization.