RNA 3'-TERMINAL PHOSPHATE CYCLASE ACTIVITY AND RNA LIGATION IN HELA-CELL EXTRACT
RNA 3'-TERMINAL PHOSPHATE CYCLASE ACTIVITY AND RNA LIGATION IN HELA-CELL EXTRACT
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DOI：
10.1093/nar/11.5.1405
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发表时间：
1983-01-01
影响因子：
14.9
通讯作者：
SHATKIN, AJ
中科院分区：
文献类型：
--
作者：
FILIPOWICZ, W;KONARSKA, M;SHATKIN, AJ
HeLa细胞提取物含有RNA连接酶活性，可将线性多核糖核苷酸转化为共价闭合环。含有2′，3 ′-环磷酸和5′-羟基末端的RNA底物通过形成正常的3′，5 ′磷酸二酯键而环化。该活性不同于先前描述的小麦胚芽RNA连接酶，其通过2′-磷酸单酯、3′，5 ′-磷酸二酯键使具有2′，3 ′-环状和5′磷酸末端的分子环化（Konarska et al.，Nature 293，112-116，1981; Proc.Natl. Acad. Sci. USA 79，1471-1478，1982）。HeLa细胞连接酶还可以利用具有3′-磷酸末端的分子。然而，在这种情况下，连接之前，通过一种新的活性，RNA 3 ′-末端磷酸环化酶，3′-末端磷酸向2′，3 ′环形式的ATP依赖性转化。RNA连接酶和RNA 3′-末端磷酸环化酶活性也存在于爪蟾卵母细胞核提取物中，与RNA加工中的作用一致。
HeLa cell extract contains RNA ligase activity that converts linear polyribonucleotides to covalently closed circles. RNA substrates containing 2′,3′-cyclic phosphate and 5′-hydroxyl termini are circularized by formation of a normal 3′,5′ phosphodiester bond. This activity differs from a previously described wheat germ RNA ligase which circularizes molecules with 2′,3′-cyclic and 5′ phosphate ends by a 2′-phosphomonoester, 3′,5′-phosphodiester linkage (Konarska et al., Nature 293, 112–116, 1981; Proc. Natl. Acad. Sci. USA 79, 1471–1478, 1982). The HeLa cell ligase can also utilize molecules with 3′-phosphate ends. However, in this case ligation is preceded by an ATP-dependent conversion of the 3′-terminal phosphate to the 2′,3′ cyclic form by a novel activity, RNA 3′-terminal phosphate cyclase. Both RNA ligase and RNA 3′-terminal phosphate cyclase activities are also present in extract of Xenopus oocyte nuclei, consistent with a role in RNA processing.