Bhattacharya S, Bhattacharya A, Diamond L S, Soldo A T
Laboratory of Parasitic Diseases, NIAID, Bethesda, Maryland 20892.
J Protozool. 1989 Sep-Oct;36(5):455-8. doi: 10.1111/j.1550-7408.1989.tb01080.x.
The presence of repeated DNA sequences encoding RNA in Entamoeba histolytica has been reported. In the present study we demonstrate by agarose gel electrophoresis. DNase digestion and electron microscopic analysis that these genes are located on extrachromosomal circular DNA molecules with an approximate size of 26 kb. Detection of replication intermediates suggests the episomal nature of these molecules. Amplified, extrachromosomal rRNA genes appear to be a common feature among the lower eukaryotes, occurring more commonly as linear molecules and less commonly as circles. Entamoeba histolytica is 1 of the few organisms studied in which rRNA genes are located predominantly on extrachromosomal circles.
据报道，溶组织内阿米巴中存在编码RNA的重复DNA序列。在本研究中，我们通过琼脂糖凝胶电泳、DNA酶消化和电子显微镜分析证明，这些基因位于大小约为26 kb的染色体外环状DNA分子上。复制中间体的检测表明这些分子具有附加体性质。扩增的染色体外rRNA基因似乎是低等真核生物中的一个共同特征，更常见的是以线性分子形式存在，以环状形式存在的较少见。溶组织内阿米巴是少数几个被研究的生物体之一，其rRNA基因主要位于染色体外环状分子上。
