Ng S Y, Parker C S, Roeder R G
Proc Natl Acad Sci U S A. 1979 Jan;76(1):136-40. doi: 10.1073/pnas.76.1.136.
When incubated with a soluble extract from large oocytes of Xenopus laevis, recombinant DNA plasmids containing either X. laevis oocyte 5S DNA or X. borealis oocyte 5S DNA direct the synthesis of discrete 5S RNAs, which by size and sequence analysis are similar or identical to the corresponding 5S RNAs synthesized in vivo. Synthesis of the 5S RNAs is mediated by a soluble endogenous RNA polymerase III (nucleosidetriphosphate:RNA nucleotidyltransferase, EC 2.7.7.6), which presumably recognizes specific initiation and termination sites in the 5S genes. Optimal conditions for accurate synthesis and the kinetics of the reactions have been determined. A soluble postchromatin supernatant fraction has also been isolated from immature oocytes. Although devoid of a functional endogenous RNA polymerase III, this extract contains a component(s) that effects the accurate transcription of 5S genes (in a plasmid) by a purified RNA polymerase III.
当与非洲爪蟾大卵母细胞的可溶性提取物一起温育时，含有非洲爪蟾卵母细胞5S DNA或北极爪蟾卵母细胞5S DNA的重组DNA质粒指导合成离散的5S RNA，通过大小和序列分析，这些5S RNA与体内合成的相应5S RNA相似或相同。5S RNA的合成由可溶性内源性RNA聚合酶III（核苷三磷酸：RNA核苷酸转移酶，EC 2.7.7.6）介导，该酶可能识别5S基因中的特定起始和终止位点。已确定了精确合成的最佳条件和反应动力学。还从未成熟卵母细胞中分离出一种可溶性染色质后上清液组分。虽然缺乏功能性内源性RNA聚合酶III，但该提取物含有一种成分，可通过纯化的RNA聚合酶III影响（质粒中）5S基因的精确转录。
