Genetic organization of the ribosomal transcription units of the yeast Saccharomyces carisbergensis

Meyerink, J.H.; Retèl, J.; Raué, H.A.; Planta, R.J.; Vanderende, A; Vanbruggen, Efj

doi:10.1093/nar/5.8.2801

Cited by 6 publications

(3 citation statements)

References 16 publications

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“…R-loop formation and specimen preparation: R-loops were formed as described previously (7) according to the method of Thomas et al (15). The R-loop mixture as well as the purified rDNA were spread and mounted on grids essentially in the same way as earlier described (7). Electron microscopy: Specimens were examined in a Philips E.M. 200 or 201 electron microscope.…”

Section: Methodsmentioning

confidence: 99%

“…Electron microscopy: Specimens were examined in a Philips E.M. 200 or 201 electron microscope. Photography and length determination were carried out as described previously (7). RESULTS~ Nucleic Acids Research proportion of the molecules appeared to be circular.…”

Section: Methodsmentioning

confidence: 99%

“…rDNA in yeast comprises 100-140 copies of a basic repeating unit, which are organized into long tandem arrays on the chromosome (7)(8)(9)(10)(11)(12). We…”

Section: Introductionmentioning

confidence: 99%

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Extrachromosomal circular ribosomal DNA in the yeast Saccharomyces carlsbergensis

et al. 1979

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Purified ribosomal DNA from Saccharomyces carlsbergensis contains a small proportion of circular DNA molecules with a contour length of 3 micron or integral multiples thereof. Hybridization of yeast ribosomal DNA with 26 S rRNA, using the R-loop technique, reveals that these circular molecules contain sequences complementary to yeast ribosomal RNA. We suggest that these extrachromosomal rRNA genes may be intermediates in the amplification of rRNA genes in yeast.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Extrachromosomal circular ribosomal DNA in the yeast Saccharomyces carlsbergensis

et al. 1979

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Denaturation mapping of the ribosomal DNA of Saccharomyces cerevisiae

Cramer

Rownd

1980

Molec. Gen. Genet.

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The thermal melting profile of purified Saccharomyces cerevisiae ribosomal DNA (rDNA) is biphasic indicating considerable intramolecular heterogeneity in base composition. The first phase of the transition, about 20% of the total hyperchromic shift, has a Tm of 80.6 degrees C and the second phase has a Tm of 87.3 degrees C, corresponding to GC contents of 28 and 44%, respectively. The Tm of the nonribosomal nuclear DNA, called alpha DNA, is 85.7 degrees C. This heterogeneity in GC distribution in the rDNA is also reflected in its denaturation map. A denaturation map of the 5.6 X 10(6) dalton rDNA SmaI restruction fragment, which represents monomer units of the rDNA, shows that specific regions of the repeating unit denature more readily than the remainder and apparently have a significantly higher AT content. By aligning the rDNA denaturation map with the restriction endonuclease map, we have been able to determine that the AT-rich segments are localized in the transcribed and nontranscribed spacer regions of the rDNA repeating unit. Buoyant density determinations of individual rDNA restriction fragments corroborate the locations of AT-rich regions. A denaturation map of the tandem repeating units in higher molecular weight rDNA has also been constructed and compared with the map of the SmaI fragment. The results show that the repeating units are uniform in size, that they are not separated by large heterogeneous regions, and that they are arranged in head-to-tail array.

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Organization of ribosomal RNA genes in the fungus Cochliobolus heterostrophus

Turgeon

Selker

et al. 1988

Curr Genet

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The genes encoding the 17S, 5.8S and 25S ribosomal RNAs in the Ascomycete Cochliobolus heterostrophus were cloned and analyzed. They are arranged in tandemly repeated units (rDNA) either 9.0 or 9.15 kilobases in length, depending upon the strain. The 5S rRNA genes are not part of the tandemly repeated rDNA. Instead, many and perhaps all of the 5S genes are dispersed in the genome, as they are in the fungi Neurospora, Aspergillus and Schizosaccharomyces. Comparative restriction maps of the rDNA from C. heterostrophus and other filamentous fungi and yeasts are presented. A survey of rDNAs from twenty-three field isolates of C. heterostrophus collected worldwide demonstrated that each isolate has one or the other of two rDNA forms, which differ in length and in the presence or absence of at least three restriction enzyme sites. The differences are all located in spacer DNA outside the coding regions for the rRNA genes. Heterogeneity in the rDNA repeat was not observed within any single isolate. The copy number of the rRNA gene cluster in C. heterostrophus is approximately 130 per haploid genome.

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Genetic organization of the ribosomal transcription units of the yeast Saccharomyces carisbergensis

Cited by 6 publications

References 16 publications

Extrachromosomal circular ribosomal DNA in the yeast Saccharomyces carlsbergensis

Extrachromosomal circular ribosomal DNA in the yeast Saccharomyces carlsbergensis

Denaturation mapping of the ribosomal DNA of Saccharomyces cerevisiae

Organization of ribosomal RNA genes in the fungus Cochliobolus heterostrophus

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