Hattori M, Ljljana A, Sakaki Y
Nucleic Acids Res. 1984 Feb 24;12(4):2047-53. doi: 10.1093/nar/12.4.2047.
Sequence homology was found between the external transcribed spacer and the terminal non-transcribed spacer of Physarum polycephalum rDNA. The homologous sequences were located 2kb upstream from the 19s rRNA gene and 0.3kb downstream from 26S rRNA gene, respectively, and were arranged in a direct repeat manner. Sequence analyses showed that the direct repeats consisted of two parts: one was sequences of about 130bp which showed over 90% sequence homology with each other. The other consisted mainly of many tandem repeats of a 50 to 52bp unit. The direct repeat-rRNA genes-direct repeat unit was found to be flanked by short direct repetitious sequences. Based on these findings, the significance of the direct repeat is discussed in terms of evolution of rDNA.
在多头绒泡菌核糖体DNA的外部转录间隔区和末端非转录间隔区之间发现了序列同源性。同源序列分别位于19s rRNA基因上游2kb处和26S rRNA基因下游0.3kb处,并以正向重复的方式排列。序列分析表明,正向重复由两部分组成:一部分是约130bp的序列,它们之间的序列同源性超过90%。另一部分主要由一个50至52bp单位的许多串联重复组成。发现正向重复-rRNA基因-正向重复单元两侧是短的正向重复序列。基于这些发现,从核糖体DNA的进化角度讨论了正向重复的意义。