Harpold M M, Dobner P R, Evans R, Bancroft F C, Darnell J E
Nucleic Acids Res. 1979 Jul 11;6(9):3133-44. doi: 10.1093/nar/6.9.3133.
A recombinant DNA plasmid, pBR322-GH1, which contains about 80% of the sequences of rat pregrowth hormone (pGH) mRNA, allowed an analysis of nuclear RNA from GH3 cells for possible precursors of cytoplasmic pGH mRNA. A single 20-22S RNA SPECIES ABOUT 2-3 TIMes larger than pGH mRNA was detected in nuclear RNA from GH3 cells labeled for 5 min. with 3H-uridine. After longer label times a 12S RNA indistinguishable in size from cytoplasmic 12S pGH mRNA became the predominant labeled RNA complementary to the plasmid pBR322-GH1. Both of these nuclear RNA species contained poly (A). Kinetic analysis of the labeling of nuclear and cytoplasmic pGH mRNA sequences showed that the 20S and 12S nuclear RNA molecules were labeled before significant labeling of cytoplasmic pGH mRNA was detected, and also indicated that there is complete conservation of nuclear pGH mRNA sequences in the production of cytoplasmic pGH mRNA. These results indicate that cytoplasmic pGH mRNA is generated by nuclear processing of a larger nuclear RNA molecule.
一种重组DNA质粒pBR322 - GH1,它包含大鼠前生长激素(pGH)mRNA约80%的序列,使得对GH3细胞的核RNA进行分析,以寻找细胞质pGH mRNA可能的前体成为可能。在用³H - 尿苷标记5分钟的GH3细胞核RNA中,检测到一种比pGH mRNA大约2 - 3倍大的单一20 - 22S RNA种类。在更长的标记时间后,一种大小与细胞质12S pGH mRNA无法区分的12S RNA成为与质粒pBR322 - GH1互补的主要标记RNA。这两种核RNA种类都含有聚腺苷酸(poly (A))。对核和细胞质pGH mRNA序列标记的动力学分析表明,在检测到细胞质pGH mRNA有明显标记之前,20S和12S核RNA分子就已被标记,并且还表明在细胞质pGH mRNA的产生过程中,核pGH mRNA序列是完全保守的。这些结果表明,细胞质pGH mRNA是由一个更大的核RNA分子经过核加工产生的。