title: Extrachromosomal rDNA of Tetrahymena thermophila is not a perfect palindrome.
abstract: We have determined the restriction-endonuclease-cleavage map and the nucleotide sequence of the central 1.4 kb fragment of the macronuclear extrachromosomal rDNA of Tetrahymena thermophila. These data demonstrate that this molecule is not a perfect palindrome, having a 29 bp AT-rich non-palindromic sequence at its center. This observation is important in determining the mechanism by which a single chromosomally integrated rRNA gene in the micronucleus is rearranged and amplified during sexual development to yield multiple copies of extrachromosomal rDNA in the macronucleus.
mesh_terms: D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping; D004262:DNA Restriction Enzymes / Q000378:metabolism; D005111:Extrachromosomal Inheritance; D005796:Genes; D009690:Nucleic Acid Conformation; D012335:RNA, Ribosomal / Q000235:genetics*; D013768:Tetrahymena / Q000235:genetics*
chemical_list: D012335:RNA, Ribosomal; D004262:DNA Restriction Enzymes