Role of the 3'-poly(A) sequence in translational regulation of mRNAs in Xenopus laevis oocytes.
Role of the 3'-poly(A) sequence in translational regulation of mRNAs in Xenopus laevis oocytes.
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DOI：
10.1016/s0021-9258(18)60631-3
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发表时间：
1988-04
期刊：
影响因子：
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通讯作者：
G. Galili;E. E. Kawata-E.;L. D. Smith;B. Larkins
中科院分区：
文献类型：
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作者：
G. Galili;E. E. Kawata-E.;L. D. Smith;B. Larkins
我们通过将SP 6转录本注射到第6阶段非洲爪蟾卵母细胞中，研究了3 '-非编码序列和poly（A）序列对膜结合mRNA（玉米醇溶蛋白）和游离mRNA（非洲爪蟾β-珠蛋白）的翻译和稳定性的影响。对于玉米醇溶蛋白mRNA，3 '-非编码序列或poly（A）序列的存在或缺失对24小时内mRNA的稳定性几乎没有影响，并且3'-非编码序列在mRNA翻译中基本上没有作用。在短时间的孵育下，例如1-2小时，多聚腺苷酸尾的存在或不存在对玉米醇溶蛋白mRNA的翻译也几乎没有影响;但在较长时间后，多聚腺苷酸mRNA的翻译显著减少。对于多聚（A+）和多聚（A-）非洲爪蟾β-珠蛋白mRNA，观察到类似的mRNA翻译模式。翻译效率的这些差异与聚（A+）玉米醇溶蛋白mRNA形成最大负载的多聚核糖体（7 - 8个核糖体/mRNA）和聚（A-）玉米醇溶蛋白mRNA不能形成大的多聚核糖体有关。这些结果与mRNA的3 '-poly（A）序列在蛋白质合成期间促进核糖体再起始的模型一致。
We investigated the effect of 3'-noncoding and poly(A) sequences on the translation and stability of membrane-bound mRNA (maize zein) and free mRNA (Xenopus beta-globin) by injecting SP6 transcripts into stage 6 Xenopus oocytes. With zein mRNA, the presence or absence of a 3'-noncoding or poly(A) sequence had little effect on mRNA stability over 24 h, and the 3'-noncoding sequence played essentially no role in mRNA translation. With short periods of incubation, e.g. 1-2 h, the presence or absence of a poly(A) tail also had little effect on zein mRNA translation; but after longer periods, translation of the poly(A-) mRNA was significantly reduced. A similar pattern of mRNA translation was observed for poly(A+) and poly(A-) Xenopus beta-globin mRNAs. These differences in translational efficiency correlated with the formation of maximally loaded polysomes (seven-eight ribosomes/mRNA) for the poly(A+) zein mRNA and a failure to form large polysomes with the poly(A-) zein mRNA. These results are consistent with a model in which the 3'-poly(A) sequence of mRNAs facilitates reinitiation of ribosomes during protein synthesis.