TERMINAL RIBOADENYLATE TRANSFERASE IN HUMAN LYMPHOCYTES
TERMINAL RIBOADENYLATE TRANSFERASE IN HUMAN LYMPHOCYTES
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DOI：
10.1038/248407a0
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发表时间：
1974-01-01
期刊：
影响因子：
64.8
通讯作者：
BOLLUM, FJ
中科院分区：
文献类型：
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作者：
COLEMAN, MS;HUTTON, JJ;BOLLUM, FJ
末端核糖体腺苷酸转移酶（TrT）在Mn2+存在下催化腺苷酸残基从ATP转移到某些多核糖核苷酸的3 ' -羟基。这类酶可能参与真核细胞中异质核RNA到mRNA的加工，因为许多类型的mRNA具有末端poly (A)序列。这方面的证据是相当零碎的，并且由于在细胞核和细胞质中有几种形式的聚(A)-聚合活性的报道而变得更加复杂。可以从实验操作的系统中获得更清晰的证据，以显示poly(A)聚合酶活性水平和mRNA合成速率的变化。我们发现人类淋巴细胞在体外对植物血凝素（PHA）刺激的反应中表现出增加的TrT活性。这是首次在哺乳动物的非病毒系统中观察到TrT活性随着细胞生理状态的变化而增加。PHA刺激的淋巴细胞可能适合用于联合聚合酶- mRNA转换研究，旨在阐明mRNA加工和末端poly (A)添加的酶促步骤，因为Rosenfeldet等人报道了PHA转化淋巴细胞过程中富含poly (A)的mRNA的增加。
TERMINAL riboadenylate transferase (TrT) catalyses the transfer of adenylate residues from ATP to the 3′-hydroxyl group of certain polyribonucleotides in the presence of Mn2+. Enzymes of this kind may be involved in the processing of heterogeneous nuclear RNA to mRNA in eukaryotic cells, since many types of mRNA have terminal poly (A) sequences. Evidence for this is rather fragmentary and is complicated by reports of several forms of poly (A)-polymerising activities in both nucleus and cytoplasm1–10. Clearer evidence might be obtained from systems that could be experimentally manipulated to show variation in the levels of activity of poly(A) polymerases and rates of mRNA synthesis. We have found that human lymphocytes exhibit increased TrT activity as part of their response to stimulation by phytohaemagglutinin (PHA)in vitro. This is the first mammalian, non-viral system in which increases in TrT activity have been observed with changes in the physiological state of the cell. The PHA-stimulated lymphocyte may be suitable for combined polymerase–mRNA turnover studies designed to clarify enzymatic steps in mRNA processing and terminal poly (A) addition, since Rosenfeldet al.11have reported increases in poly (A)-rich mRNA during lymphocyte transformation by PHA.