Unique arrangement of coding sequences for 5 S, 5.8 S, 18 S and 25 S ribosomal RNA in Saccharomyces cerevisiae as determined by R-loop and hybridization analysis

摘要: Abstract The arrangement of the coding sequences for 5 S, 5.8 18 S and 25 ribosomal RNA from Saccharomyces cerevisiae was analyzed in λ-yeast hybrids containing repeating units DNA. After mapping restriction sites, positions were determined by hybridization purified rRNAs to fragments, R-loop analysis electron microscope, electrophoresis 1 nuclease-treated rRNA/rDNA alkaline agarose gels. method improved with respect length calibration RNA/DNA duplexes spreading conditions resulting fully extended rRNA R-loops. qualitative results are: (1) genes, unlike those higher eukaryotes, alternate genes precursor rRNA; (2) sequence maps, as between sequences. quantitative tandemly rDNA have a constant 9060 ± 100 nucleotide pairs one Sst I, two Hin dIII and, dependent on strain, six or seven Eco RI sites; regions consist 1710 80 3360 pairs, respectively; (3) an region is separated 780 70 transcribed spacer region. This then followed 3210 mainly non-transcribed which contains gene.