Levens D, Ticho B, Ackerman E, Rabinowitz M
J Biol Chem. 1981 May 25;256(10):5226-32.
We have used vaccinia virus guanylyltransferase to label polyphosphate-terminated yeast mitochondrial RNAs in vitro with [alpha-32P]GTP. Hybridization of RNA labeled in vitro indicates the presence of multiple transcriptional initiation sites in both grande and petite mitochondrial genomes. Agarose/urea gel electrophoresis of capped RNA suggests the existence of a precursor to the small (14 S) rRNA. In contrast, direct examination of the large (21 S) rRNA by partial ribonuclease T1 digestion reveals a complete lack of processing of the 5' end of the primary transcript of this RNA.
我们利用痘苗病毒鸟苷酸转移酶，在体外使用[α-32P]GTP对多磷酸末端的酵母线粒体RNA进行标记。体外标记RNA的杂交表明，在大、小线粒体基因组中均存在多个转录起始位点。加帽RNA的琼脂糖/尿素凝胶电泳表明存在小（14S）rRNA的前体。相比之下，通过核糖核酸酶T1部分消化直接检测大（21S）rRNA，发现该RNA初级转录本的5'端完全没有加工。
