title: Isolation and mapping of the rRNA genes in the macronucleus of Oxytricha fallax.
abstract: The DNA in the macronucleus of the protozoan Oxytricha, unlike like that of typical eukaryotes, exists as short, gene-sized molecules. Within the macronucleus the rRNA genes are contained in molecules 7,380 nucleotide pairs in length. This rDNA has been substantially purified by selective denaturation of non-ribosomal DNA followed by S1 nuclease digestion. Results from restriction nuclease digestion and rRNA:DNA hybridization who that the rDNA is a linear, non-palindromic molecule which contains one gene each for the 19s and 25s rRNAs. A total of less than 600 base pairs of DNA lies between the 19s and 25s genes or at the 3' end of the 25s gene. The non-coding portion of the ribosomal DNA is almost entirely limited to an approximately 1,400 base pair region at the 5' end of the molecule.
mesh_terms: D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping; D016798:Ciliophora / Q000235:genetics*; D004247:DNA / Q000302:isolation & purification*; D004262:DNA Restriction Enzymes; D004587:Electrophoresis, Agar Gel; D005796:Genes; D009693:Nucleic Acid Hybridization; D012335:RNA, Ribosomal / Q000235:genetics*
chemical_list: D012335:RNA, Ribosomal; D004247:DNA; D004262:DNA Restriction Enzymes