Arrangement of individual human ribosomal DNA fragments on stretched DNA fibers.
We studied the arrangement of individual human ribosomal (r)DNA repeats by direct visualization of rDNA sequences. We used high resolution fluorescence in situ hybridization on preparations of DNA fibers released from interphase nuclei of HeLa cells. Probes from both the transcription unit and the intergenic spacer were used, and lengths of signals and of the gaps in between were measured and compared to molecular data. We could visualize the repetitive arrangement of individual rDNA sequences at the single gene level. No inversions or deletions were detected. The intergenic spacer was found to be shorter than expected, indicating a length polymorphism.
Institute for Histology and Embryology, University of Vienna, Austria. christian.schoefer@univie.ac.at
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Schöfer
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Weipoltshammer
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Almeder
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Wachtler
D002467:Cell Nucleus; D015342:DNA Probes; D004275:DNA, Ribosomal / Q000032:analysis* / Q000737:chemistry; D006367:HeLa Cells; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007399:Interphase; D007438:Introns / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping / Q000379:methods*; D012270:Ribosomes / Q000235:genetics*; D017422:Sequence Analysis, DNA; D014158:Transcription, Genetic
D015342:DNA Probes; D004275:DNA, Ribosomal