The differential analyses of tRNA splicing processes among the three domains of life

在真核生物中，一些tRNA基因含有内含子。由于前体tRNA（pre-tRNA）在蛋白质生物合成中没有功能，因此必须精确去除内含子。最近，发现RtcB催化来自前体tRNA的外显子的连接。RtcB似乎还催化来自前tRNA的内含子的循环。事实上，我们在产甲烷古菌Methanosarcina acetivorans细胞中发现了环状内含子。尽管环化内含子具有任何功能或不具有任何功能，但我们认为它是功能性的，因为以下事实。首先，环化内含子在M.醋酸菌细胞其次，RtcB甚至存在于任何tRNA基因都不含内含子的细菌细胞中。在未来，我们希望发现小环状RNA的功能。

In Archaea and Eucarya, some tRNA genes contain introns. Since the precursor tRNA (pre-tRNA) is not functional in protein biosynthesis, exact removal of introns must be essential. Recently, it was found that the RtcB catalyzes the ligation of exons derived from the pre-tRNA. RtcB also seems to catalyze the circulation of intron from pre-tRNA. In fact, we found the circularized intron in methanogenic archaeon, Methanosarcina acetivorans, cells. Whereas the circularized intron has any function or not, we believe it would be functional because of the following facts. First, the circularized intron was stable in M. acetivorans cells. Second, RtcB even exists in bacterial cells that any tRNA gene does not contain intron. In future, we would like to discover the functions of small circularized RNAs.