Karin M, Holtgreve H
DNA. 1984 Aug;3(4):319-26. doi: 10.1089/dna.1.1984.3.319.
The transient expression of the human metallothionein-IIA (hMT-IIA) gene was examined after introduction into NIH-3T3 cells. A series of deletion mutants within the 5' flanking region of the hMT-IIA gene was constructed and fused to the structural sequences of the Herpes simplex thymidine kinase (TK) gene to generate hMTK chimeric genes. During transient expression, the hMTK gene is responsive to both ligands. In addition we find at least 92 bp of 5' flanking DNA are required for both transient expression and induction by Cd2+, in contrast to only 50 bp required for induction by the heavy metal ions of the same gene in stable transformants. This difference is due to a deletion of a regulatory element, located between nucleotides -70 to -90 of the hMT-IIA gene, which functions to maintain basal expression in the absence of inducers. This element is absolutely required for transient expression of the hMT-IIA gene.
将人金属硫蛋白-IIA（hMT-IIA）基因导入NIH-3T3细胞后，对其瞬时表达进行了检测。构建了hMT-IIA基因5'侧翼区域内的一系列缺失突变体，并将其与单纯疱疹胸苷激酶（TK）基因的结构序列融合，以产生hMTK嵌合基因。在瞬时表达过程中，hMTK基因对两种配体均有反应。此外，我们发现5'侧翼DNA至少92 bp对于瞬时表达和Cd2+诱导都是必需的，相比之下，在稳定转化体中同一基因的重金属离子诱导仅需50 bp。这种差异是由于hMT-IIA基因核苷酸-70至-90之间的一个调控元件缺失所致，该元件在没有诱导剂的情况下维持基础表达。这个元件对于hMT-IIA基因的瞬时表达是绝对必需的。
