Lane B G, Tumaitis-Kennedy T D
Eur J Biochem. 1981 Mar;114(3):457-63. doi: 10.1111/j.1432-1033.1981.tb05167.x.
There has been no previous study of levels of secondary processing in the template-active RNA of dry seeds and embryos. Such information is needed to evaluate the role of transcription in changing the cell-free translational capacity of bulk RNA during early imbibition of water by dry wheat embryos [J. Biol. Chem. 255, 5969-5970 (1980)]. Although it probably contains a higher proportion of "hidden breaks' than bulk mRNA from imbibing embryos, bulk mRNA in dry wheat embryos is also "capped' by 7-methylguanosine at 5' termini, devoid of unmethylated "caps', methylated internally (N6-methyladenosine) and polyadenylated at 3' termini. In contrast to other developing systems, there is no evidence that there are signal changes in levels of secondary processing in the bulk mRNA populations which support change in cell-free translational capacity of RNA 1-5 h postimbibition of dry wheat embryos. Change in the pattern of protein synthesis 5-24 h postimbibition also takes place without signal changes in levels of secondary processing in template-active RNA. The analytical data are evaluated and discussed in terms of difficulties allied with comparative analyses of poly(A)-rich RNA from dry and imbibing embryos, the former being refractory to, and the latter being most easily analyzed by, labeling in vivo.
此前尚无关于干燥种子和胚的模板活性RNA中二级加工水平的研究。在评估干燥小麦胚早期吸水过程中转录在改变大量RNA的无细胞翻译能力方面的作用时，需要此类信息[《生物化学杂志》255, 5969 - 5970 (1980)]。尽管与吸水胚的大量mRNA相比，干燥小麦胚的大量mRNA可能含有更高比例的“隐蔽断裂”，但干燥小麦胚中的大量mRNA在5'末端也被7 - 甲基鸟苷“加帽”，没有未甲基化的“帽”，内部甲基化（N6 - 甲基腺苷）并在3'末端多聚腺苷酸化。与其他发育系统不同，没有证据表明在干燥小麦胚吸水后1 - 5小时，大量mRNA群体的二级加工水平存在信号变化以支持RNA无细胞翻译能力的改变。吸水后5 - 24小时蛋白质合成模式的变化也在模板活性RNA的二级加工水平没有信号变化的情况下发生。根据与干燥和吸水胚富含多聚腺苷酸RNA的比较分析相关的困难对分析数据进行了评估和讨论，前者难以进行体内标记，而后者最容易通过体内标记进行分析。
