title: rRNA genes of Naegleria gruberi are carried exclusively on a 14-kilobase-pair plasmid.
abstract: An extrachromosomal DNA was discovered in Naegleria gruberi. The 3,000 to 5,000 copies per cell of this 14-kilobase-pair circular plasmid carry all the 18S, 28S, and 5.8S rRNA genes. The presence of the ribosomal DNA of an organism exclusively on a circular extrachromosomal element is without precedent, and Naegleria is only the third eucaryotic genus in which a nuclear plasmid DNA has been found.
authors.affiliation: Rockefeller University, New York, New York 10021-6399.
authors.forename: C G
authors.initials: CG
authors.lastname: Clark
authors.forename: G A
authors.initials: GA
authors.lastname: Cross
mesh_terms: D000818:Animals; D002874:Chromosome Mapping; D004262:DNA Restriction Enzymes; D004275:DNA, Ribosomal / Q000235:genetics*; D005796:Genes; D009253:Naegleria / Q000235:genetics*; D010957:Plasmids; D012335:RNA, Ribosomal / Q000235:genetics*
chemical_list: D004275:DNA, Ribosomal; D012335:RNA, Ribosomal; D004262:DNA Restriction Enzymes