Sagata N, Shiokawa K, Yamana K
J Exp Zool. 1980 Jul;213(1):117-22. doi: 10.1002/jez.1402130112.
Using a 3H-poly(U) binding technique, poly(A) content has been measured in Xenopus laevis eggs consisting of two groups: one was obtained from females 12 to 16 hr after a single injection of human chorionic gonadotropin (HCG) (designated "unstimulated" eggs), and the other was obtained one week later from the same females by the second injection of the hormone ("stimulated" eggs). The stimulated egg contained about a 1.2-fold larger amount of poly(A) than the unstimulated one. Gel electrophoresis has revealed that this slight but reproducible increase in the poly(A) content was due to the production of a specific size class of poly(A) (i.e., about 80 nucleotides long). This poly(A) was also detectable in the oocytes obtained one week after a single injection but not in those from uninjected females. Poly(A)+RNA was analyzed by sucrose density gradient centrifugation, and it has been shown that most of the 80 nucleotide-long poly(A) sequences in the stimulated eggs were associated with RNA whose size distribution was less heterogeneous than, and hence distinguishable from, that of the bulk poly(A)+RNA. The possibility is discussed that HCG hormone may stimulate the synthesis of a specific class of poly(A)+RNA in smaller oocytes, which may not normally take place to a significant extent during maturation.
利用³H-聚（U）结合技术，对非洲爪蟾卵母细胞中的聚（A）含量进行了测定，这些卵母细胞分为两组：一组是在单次注射人绒毛膜促性腺激素（HCG）后12至16小时从雌性个体获取的（称为“未受刺激”的卵母细胞），另一组是一周后通过第二次注射该激素从同一雌性个体获取的（“受刺激”的卵母细胞）。受刺激的卵母细胞所含聚（A）的量比未受刺激的卵母细胞大约多1.2倍。凝胶电泳显示，聚（A）含量的这种轻微但可重复的增加是由于产生了特定大小类别的聚（A）（即长度约为80个核苷酸）。在单次注射一周后获得的卵母细胞中也可检测到这种聚（A），但在未注射的雌性个体的卵母细胞中则未检测到。通过蔗糖密度梯度离心对聚（A）⁺RNA进行了分析，结果表明，受刺激的卵母细胞中大多数80个核苷酸长的聚（A）序列与RNA相关联，其大小分布比整体聚（A）⁺RNA的大小分布更均匀，因此可以区分。文中讨论了一种可能性，即HCG激素可能刺激较小卵母细胞中特定类别的聚（A）⁺RNA的合成，而这种合成在成熟过程中通常不会大量发生。
