DiSSU1 is an optional group I twintron present in the nuclear extrachromosomal ribosomal DNA of the myxomycete Didymium iridis. DiSSU1 appears to be complex both in structure and function. At the RNA level it has a twin-ribozyme organization composed of two group I ribozymes with different functions, separated by an open reading frame. Here, we show that DiSSU1 is mobile when haploid intron-containing and intron-less amoebae are mated. The mobility process is fast, being completed in 5-10 nuclear cycles after mating in the developing zygote and plasmodia. Analyses of progeny from genetic crosses confirm intron mobility. DiSSU1 is the first example of a mobile group I twintron. The intron-encoded protein was expressed in Escherichia coli and found to be an endonuclease, I-DirI, that cleaves an intron-less ribosomal DNA allele at the intron-insertion site, and is probably involved in intron homing. The endonuclease I-DirI seems to be a rare example of a protein that is expressed from a ribozyme-processed RNA polymerase I transcript in vivo.

译文

DiSSU1是一种可选的I族双冠子,存在于粘菌素二钕虹膜的核染色体外核糖体DNA中。DiSSU1在结构和功能上似乎都很复杂。在RNA水平上,它具有一个双核酶组织,该组织由两个具有不同功能的I族核酶组成,并由开放阅读框隔开。在这里,我们表明,当单倍体内含子和无内含子的阿米巴交配时,DiSSU1是可移动的。迁移率过程很快,在发育中的合子和疟原虫交配后,在5-10个核循环中完成。对遗传杂交后代的分析证实了内含子的迁移率。DiSSU1是移动组I twintron的第一个示例。内含子编码的蛋白在大肠杆菌中表达,发现它是一种内切核酸酶I-DirI,在内含子插入位点切割无内含子核糖体DNA等位基因,并且可能参与内含子归巢。核酸内切酶I-DirI似乎是从核酶处理的RNA聚合酶I转录本体内表达的蛋白质的罕见例子。

+1
+2
100研值 100研值 ¥99课程
检索文献一次
下载文献一次

去下载>

成功解锁2个技能,为你点赞

《SCI写作十大必备语法》
解决你的SCI语法难题!

技能熟练度+1

视频课《玩转文献检索》
让你成为检索达人!

恭喜完成新手挑战

手机微信扫一扫,添加好友领取

免费领《Endnote文献管理工具+教程》

微信扫码, 免费领取

手机登录

获取验证码
登录