Kindle K L, Firtel R A
Cell. 1978 Nov;15(3):763-78. doi: 10.1016/0092-8674(78)90262-3.
Plasmid M6 has been shown to contain sequences complementary to two related abundant mRNA species which differ in length by 100 nucleotides and code for Dictyostelium actin. M6 complementary RNA was isolated by hybridization to immobilized M6 DNA and translated in vitro. The product is identical to major forms of in vivo labeled actin in both mobility on two-dimensional gels and two-dimensional fingerprints of tryptic peptides. Both plasmid M6 and a second plasmid complementary to the actin mRNA complementary region in M6, pDd actin 2 (McKeown et al., 1978), direct the synthesis in minicells of a number of similar polypeptides that are not seen in minicells containing other recombinant plasmids. Three of these polypeptides are similar in two-dimensional gel mobility to Dictyostelium actin and bind to DNAse I agarose. The repetition frequency of isolated restriction fragments from actin mRNA complementary plasmid M6 has been examined. The data from two different experimental approaches (DNA excess hybridizations using plasmid DNA as probe, and hybridization of plasmid probe to DNA blot filters of restriction enzyme-digested Dictyostelium DNA) indicate that the mRNA complementary region is reiterated 15--20 times. When an actin cDNA probe is used in the same experiments, the results suggest that the entire coding region is reiterated. When the two major actin mRNA species are separated and independently translated, each appears to code for one of the two major actin species. The results suggest that there are at least two different functional genes, and possibly more, for Dictyostelium actin.
已证明质粒M6含有与两种相关的丰富mRNA物种互补的序列，这两种mRNA物种长度相差100个核苷酸，编码盘基网柄菌肌动蛋白。通过与固定化的M6 DNA杂交分离出M6互补RNA，并进行体外翻译。该产物在二维凝胶上的迁移率以及胰蛋白酶肽的二维指纹图谱方面，均与体内标记的肌动蛋白的主要形式相同。质粒M6和与M6中肌动蛋白mRNA互补区域互补的第二个质粒pDd肌动蛋白2（麦基翁等人，1978年），在微细胞中都指导合成许多相似的多肽，而在含有其他重组质粒的微细胞中则看不到这些多肽。其中三种多肽在二维凝胶迁移率方面与盘基网柄菌肌动蛋白相似，并与DNA酶I琼脂糖结合。已检测了从肌动蛋白mRNA互补质粒M6分离的限制性片段的重复频率。来自两种不同实验方法（以质粒DNA为探针的DNA过量杂交，以及质粒探针与限制性酶切的盘基网柄菌DNA的DNA印迹滤膜杂交）的数据表明，mRNA互补区域重复了15 - 20次。当在相同实验中使用肌动蛋白cDNA探针时，结果表明整个编码区域是重复的。当将两种主要的肌动蛋白mRNA物种分离并独立翻译时，每种似乎都编码两种主要肌动蛋白物种之一。结果表明，盘基网柄菌肌动蛋白至少有两个不同的功能基因，可能更多。
