title: Distribution of ribosomal ribonucleic acid cistrons among yeast chromosomes.
abstract: High-molecular-weight deoxyribonucleic acid (DNA) of Saccharomyces carls bergensis has been fractionated by sucrose density gradient centrifugation. The main DNA fraction has an average molecular weight of about 500 x 10(6). A major fraction of the DNA molecules containing sequences homologous to ribosomal ribonucleic acid (RNA) sediments as material of this molecular weight. The remainder sediments as material of a molecular weight of about 250 x 10(6). The latter fraction contains relatively more ribosomal RNA cistrons than the former. Studies on the buoyant density of high-molecular-weight DNA homologous to ribosomal RNA have led to the conclusion that the ribosomal RNA cistrons occur in groups attached to a relatively large amount of nonribosomal RNA and suggest that ribosomal RNA cistrons are distributed over a number of yeast chromosomes.
mesh_terms: D000225:Adenine / Q000378:metabolism; D002247:Carbon Isotopes; D002499:Centrifugation, Density Gradient; D002875:Chromosomes; D004272:DNA, Mitochondrial / Q000378:metabolism; D005796:Genes; D007454:Iodides; D008970:Molecular Weight; D009693:Nucleic Acid Hybridization; D011523:Protoplasts / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012335:RNA, Ribosomal / Q000378:metabolism*; D012440:Saccharomyces / Q000166:cytology / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000378:metabolism; D013395:Sucrose; D014316:Tritium
chemical_list: D002247:Carbon Isotopes; D004272:DNA, Mitochondrial; D007454:Iodides; D012333:RNA, Messenger; D012335:RNA, Ribosomal; D014316:Tritium; D013395:Sucrose; D000225:Adenine