Clark C G, Cross G A
Rockefeller University, New York, New York 10021-6399.
Mol Cell Biol. 1987 Sep;7(9):3027-31. doi: 10.1128/mcb.7.9.3027-3031.1987.
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.
在格氏耐格里变形虫中发现了一种染色体外DNA。这种14千碱基对的环状质粒在每个细胞中有3000到5000个拷贝，携带了所有的18S、28S和5.8S核糖体RNA基因。一种生物的核糖体DNA仅存在于环状染色体外元件上，这是前所未有的，耐格里变形虫是发现核质粒DNA的第三个真核生物属。
