METHYLATED NUCLEOTIDE-SEQUENCES IN HELA-CELL RIBOSOMAL-RNA AND ITS PRECURSORS
METHYLATED NUCLEOTIDE-SEQUENCES IN HELA-CELL RIBOSOMAL-RNA AND ITS PRECURSORS
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DOI：
10.1016/0022-2836(74)90299-x
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发表时间：
1974-01-01
影响因子：
5.6
通讯作者：
SALIM, M
中科院分区：
文献类型：
--
作者：
MADEN, BEH;SALIM, M
通过RNA指纹和测序方法检查HeLa细胞核糖体RNA及其核仁前体中的甲基化核苷酸序列。发现 18 S RNA 含有约 46 个甲基，28 S RNA 含有约 70 个甲基，5.8 S RNA 含有 1 个甲基。大多数甲基出现在不同的 T1 核糖核酸酶寡核苷酸中，并且其中大多数大约每个 18 S 或 28 S RNA 分子回收一次。然而，也有一些多甲基化寡核苷酸、一些多次出现的短产物和一些“部分”产物。绝大多数甲基化发生在 45 S RNA 水平，但另外六种甲基化发生在 18 S RNA 成熟后期，一小部分甲基化发生在 28 S 成熟期间。前体分子的转录间隔区未甲基化。对甲基化成分和序列的化学分析表明，除了五个“早期”甲基化外，所有甲基化均位于核糖基团上，其余五个甲基化位于 28 S 序列内的碱基上。晚期甲基化全部发生在碱基上，其中 4 个位于 18 S RNA 上，产生序列……Gpm2post6Apm2post6ApCp……Choi & Busch (1970) 先前报道，产物 pCmpUp 是大鼠肝癌 28 S、32 S 和 45 S RNA 的 5' 端基，但 HeLa 细胞 28 S RNA 或其前体中不存在。讨论了这项工作的意义。
The methylated nucleotide sequences in HeLa cell ribosomal RNA and its nucleolar precursors were examined by RNA fingerprinting and sequencing methods. 18 S RNA was found to contain approximately 46 methyl groups, 28 S RNA some 70 methyl groups and 5.8 S RNA one methyl group. Most methyl groups occur in different T1ribonuclease oligonucleotides, and most of these were recovered approximately once per molecule of 18 S or 28 S RNA. There are also, however, several multiply methylated oligonucleotides, a few short products that occur more than once and a few “fractional” products. The great majority of methylations occur at the level of 45 S RNA, but six further methylations occur late during the maturation of 18 S RNA, and one fractional one occurs during 28 S maturation. The transcribed spacer regions of the precursor molecules are unmethylated. Chemical analysis of the methylated components and sequences indicates that all except five “early” methylations are on ribose groups, the remaining five being on bases within the 28 S sequence. The late methylations are all on bases, four of those on 18 S RNA giving rise to the sequence, … Gpm2post6Apm2post6ApCp… The product, pCmpUp, previously reported by Choi & Busch (1970) as being the 5′ end-group of rat hepatoma 28 S, 32 S and 45 S RNA, is not present in HeLa cell 28 S RNA or its precursors. Implications of this work are discussed.