STRUCTURE AND EXPRESSION OF HUMAN ACTIN GENES

肌动蛋白是所有真核细胞的主要成分。 从功能上讲， 参与细胞骨架结构，并且这些结构在 转化细胞 去理解人类的结构和表情 肌动蛋白基因，我们已经开始对分子克隆的人类 肌动蛋白基因 人平滑肌肌动蛋白基因的DNA序列分析 （主动脉型）表明，该基因具有一个独特的内含子，在任何 其他肌动蛋白基因的分析，这表明这个内含子插入晚 在进化过程中。 平滑肌肌动蛋白基因在化学上 转化的人类细胞显示出正常细胞中没有的点突变， 细胞对应物。 研究克隆的人心肌肌动蛋白DNA是否含有序列 为了表达所需，通过以下步骤构建重组质粒： 将心肌肌动蛋白DNA插入到表达穿梭载体中， 乳头状瘤病毒DNA。 用该重组体转化的小鼠细胞 表达大量的人类心脏mRNA，并且该mRNA被 在小鼠细胞中忠实地翻译成心脏肌动蛋白。 结果 表明克隆的肌动蛋白DNA含有（在其5'和3'端内 非翻译序列）的起始和终止信号 转录以及翻译。 牛乳头瘤病毒DNA 载体可用于在小鼠中稳定表达克隆的人DNA序列 细胞

Actins are major components of all eukaryotic cells. Functionally they are involved in the cytoskeletal structures and these structures are altered in transformed cells. To understand the structure and expression of the human actin genes, we have begun a molecular analysis of molecularly cloned human actin genes. DNA sequence analysis of the human smooth muscle actin gene (aortic type) showed that this gene has a unique intron not found in any other actin genes analyzed, suggesting that this intron was inserted late in the evolutionary process. The smooth muscle actin gene in chemically transformed human cells showed a point mutation not found in the normal cell counterpart. To study whether the cloned human cardiac actin DNA contained sequences necessary for its expression, a recombinant plasmid was constructed by inserting the cardiac actin DNA into the expression shuttle vector, bovine papilloma viral DNA. Mouse cells transformed with this recombinant expressed a substantial amount of the human cardiac mRNA and this mRNA was faithfully translated into cardiac actin in mouse cells. The results indicate that the cloned actin DNA contains (within its 5' and 3' untranslated sequences) signals for the initiation and termination of transcription as well as for translation. Bovine papilooma viral DNA vectors can be used to stably express cloned human DNA sequences in mouse cells.