Construction of site-directed mutant variants of ATP7B in vitro and their expression / 中华神经科杂志

ABSTRACT

Objective To study the expression of normal and variant ATP7B proteins, in order to further find the mechanism of Wilson disease. Methods Normal ATP7BcDNA/pcDNA3 was made and mutant variants Arg778Leu/pcDNA3, Gln914Ter/pcDNA3 and Thr935Met/pcDNA3 were constructed by using Quik-Change TM Site-directed Mutagenesis Kit in vitro. A good quality rabbit polyclonal antibody against the N-terminal functional domains of ATP7B was produced and purified, being named rabbit anti-human ATP7Bn33-629 polyclonal antibody. Normal and variant expression plasmids constructed above were transfected into Chinese hamster ovary (CHO) cells. After a 36-hour incubation at 37℃, the transfected CHO cells were collected. Expression of normal and variant ATP7B protein were detected and compared by Western blot analysis of cell lysates using ATP7Bn33-629 antibody. Results Expression of ATP7B normal protein in transfected CHO cells was the same as that of ATP7B variant proteins Arg778Leu and Thr935Met.Gln914Ter variant shortened ATP7B protein to 100 kd and increased the level of expression. Conclusion The mechanism under disorder of copper transport caused by the missense mutations should be not related to the level of expression. The increased level of expression caused by Gln914Ter might be associated with the shortened ATP7B protein that needs less time for translation.