Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
???displayArticle.abstract???
Telomeres are essential structures that stabilize the ends of eukaryotic chromosomes and allow complete replication of linear DNA molecules. We examined the structure and replication of telomeres by observing the fate of the linear extrachromosomal rDNA of Tetrahymena after injection into unfertilized Xenopus eggs. The rDNA replicated efficiently as a linear extrachromosomal molecule, increasing in mass 30-50-fold by 15-20 h after injection. In addition, the molecules increased in length by addition of up to several kilobases of DNA to their termini. Sequence analysis demonstrated that the added DNA bore no resemblance to known telomeres. The junction between the rDNA and added DNA was apparently random, indicating that the addition reaction did not involve a site-specific recombination or integration event. Surprisingly, Southern blot analysis showed that the added DNA did not derive from Xenopus DNA, but rather from co-purifying and therefore co-injected Tetrahymena DNA. The nonspecific ligation of random DNA fragments to the rDNA termini suggests that microinjected Tetrahymena rDNA ends are not recognized as telomeres in Xenopus eggs.
Bendig,
Persistence and expression of histone genes injected into Xenopus eggs in early development.
1981, Pubmed,
Xenbase
Bendig,
Persistence and expression of histone genes injected into Xenopus eggs in early development.
1981,
Pubmed
,
Xenbase Blackburn,
A tandemly repeated sequence at the termini of the extrachromosomal ribosomal RNA genes in Tetrahymena.
1978,
Pubmed Blackburn,
Non-nucleosomal packaging of a tandemly repeated DNA sequence at termini of extrachromosomal DNA coding for rRNA in Tetrahymena.
1981,
Pubmed Blackburn,
Telomeres: do the ends justify the means?
1984,
Pubmed Blackburn,
The molecular structure of centromeres and telomeres.
1984,
Pubmed Brown,
Specific gene amplification in oocytes. Oocyte nuclei contain extrachromosomal replicas of the genes for ribosomal RNA.
1968,
Pubmed Cech,
Localization of transcribed regions on extrachromosomal ribosomal RNA genes of Tetrahymena thermophila by R-loop mapping.
1979,
Pubmed Cheung,
Protein tightly bound near the termini of the Physarum extrachromosomal rDNA palindrome.
1981,
Pubmed Conrad,
Microcomputer programs for DNA sequence analysis.
1982,
Pubmed Dawid,
Evidence for the mitochondrial origin of frog egg cytoplasmic DNA.
1966,
Pubmed Gall,
Differential synthesis of the genes for ribosomal RNA during amphibian oögenesis.
1968,
Pubmed Gall,
Free ribosomal RNA genes in the macronucleus of Tetrahymena.
1974,
Pubmed Gottschling,
Chromatin structure of the molecular ends of Oxytricha macronuclear DNA: phased nucleosomes and a telomeric complex.
1984,
Pubmed Green,
Human beta-globin pre-mRNA synthesized in vitro is accurately spliced in Xenopus oocyte nuclei.
1983,
Pubmed
,
Xenbase Greider,
Identification of a specific telomere terminal transferase activity in Tetrahymena extracts.
1985,
Pubmed Grunstein,
Colony hybridization: a method for the isolation of cloned DNAs that contain a specific gene.
1975,
Pubmed Hara,
A cytoplasmic clock with the same period as the division cycle in Xenopus eggs.
1980,
Pubmed
,
Xenbase Harland,
Regulated replication of DNA microinjected into eggs of Xenopus laevis.
1980,
Pubmed
,
Xenbase Hines,
Initiation of replication at specific origins in DNA molecules microinjected into unfertilized eggs of the frog Xenopus laevis.
1982,
Pubmed
,
Xenbase Jamrich,
Transcription of repetitive sequences on Xenopus lampbrush chromosomes.
1983,
Pubmed
,
Xenbase Karrer,
The macronuclear ribosomal DNA of Tetrahymena pyriformis is a palindrome.
1976,
Pubmed Kavenoff,
Chromosome-sized DNA molecules from Drosophila.
1973,
Pubmed Kiss,
Two separate regions of the extrachromosomal ribosomal deoxyribonucleic acid of Tetrahymena thermophila enable autonomous replication of plasmids in Saccharomyces cerevisiae.
1981,
Pubmed Laskey,
Nucleosomes are assembled by an acidic protein which binds histones and transfers them to DNA.
1978,
Pubmed
,
Xenbase Maxam,
Sequencing end-labeled DNA with base-specific chemical cleavages.
1980,
Pubmed McClintock,
The Stability of Broken Ends of Chromosomes in Zea Mays.
1941,
Pubmed Méchali,
Lack of specific sequence requirement for DNA replication in Xenopus eggs compared with high sequence specificity in yeast.
1984,
Pubmed
,
Xenbase Messing,
A new pair of M13 vectors for selecting either DNA strand of double-digest restriction fragments.
1982,
Pubmed Newport,
A major developmental transition in early Xenopus embryos: I. characterization and timing of cellular changes at the midblastula stage.
1982,
Pubmed
,
Xenbase Pluta,
Elaboration of telomeres in yeast: recognition and modification of termini from Oxytricha macronuclear DNA.
1984,
Pubmed Rae,
5-Hydroxymethyluracil in the DNA of a dinoflagellate.
1973,
Pubmed Rigby,
Labeling deoxyribonucleic acid to high specific activity in vitro by nick translation with DNA polymerase I.
1977,
Pubmed Roberts,
In support of the telomere concept.
1975,
Pubmed Roth,
DNA intermediates and telomere addition during genome reorganization in Euplotes crassus.
1985,
Pubmed Sanger,
DNA sequencing with chain-terminating inhibitors.
1977,
Pubmed SCHILDKRAUT,
Determination of the base composition of deoxyribonucleic acid from its buoyant density in CsCl.
1962,
Pubmed Shampay,
DNA sequences of telomeres maintained in yeast.
,
Pubmed Southern,
Detection of specific sequences among DNA fragments separated by gel electrophoresis.
1975,
Pubmed Staden,
Sequence data handling by computer.
1977,
Pubmed Szostak,
Cloning yeast telomeres on linear plasmid vectors.
1982,
Pubmed Tondravi,
Transformation of Tetrahymena thermophila by microinjection of ribosomal RNA genes.
1986,
Pubmed Wyllie,
Selective DNA conservation and chromatin assembly after injection of SV40 DNA into Xenopus oocytes.
1978,
Pubmed
,
Xenbase Yao,
Repeated hexanucleotide C-C-C-C-A-A is present near free ends of macronuclear DNA of Tetrahymena.
1981,
Pubmed
