Christianson T, Edwards J, Levens D, Locker J, Rabinowitz M
J Biol Chem. 1982 Jun 10;257(11):6494-500.
We have identified the nucleotide at which transcription initiates on the yeast mitochondrial small (14 S) rRNA gene by sequencing of RNA labeled at the 5' initiating triphosphate with vaccinia virus guanylyltransferase [alpha-32P]GTP (in vitro capping reaction). Initiation occurs within the stem of a 12-base palindromic repeat. The initiation sequence has homology with the large (21 S) ribosomal RNA initiation sequence that has been previously determined. We have also sequenced the 5' and 3' ends of the mature 14 S rRNA after labeling with T4 polynucleotide kinase and RNA ligase, respectively. These sequences demonstrate that about 80 nucleotides are cleaved from the 5' end of a precursor to produce the mature 14 S rRNA. This cleavage is imprecise in that the processing occurs at one of five adjacent nucleotides 77 to 81 nucleotides downstream from the 5' initiation site. The 3' ends of this precursor and the mature 14 S rRNA are unique and identical.
我们通过对在体外封端反应中用痘苗病毒鸟苷酸转移酶[α-32P]GTP标记5'起始三磷酸的RNA进行测序，确定了酵母线粒体小（14S）rRNA基因转录起始的核苷酸。起始发生在一个12碱基回文重复序列的茎内。该起始序列与先前确定的大（21S）核糖体RNA起始序列具有同源性。我们还分别用T4多核苷酸激酶和RNA连接酶标记后，对成熟14S rRNA的5'和3'末端进行了测序。这些序列表明，从前体的5'末端切割掉约80个核苷酸以产生成熟的14S rRNA。这种切割是不精确的，因为加工发生在5'起始位点下游77至81个核苷酸处五个相邻核苷酸中的一个。该前体的3'末端与成熟14S rRNA的3'末端是独特且相同的。
