RESUMEN
In modern biology and biotechnology research, recombinant gene expression has been the most popular method to obtain the target protein. In recent years, many foreign genes have been efficiently expressed in Escherichia coli. However, proteins encoded by animal, plant or mesophilic microbial genes often lose activities or become denatured within a few hours at regular growth temperatures for E. coli; some other target proteins are toxic to host cells and therefore difficult to be over-expressed. The new T-vector, pEXC-T, was constructed by combining TA cloning and cold-shock induction to obtain high expression levels with low costs. This paper reports the construction of pEXC-T and optimization of induction techniques for gene expression. Two instable proteins were tested and successfully expressed in soluble form by using pEXC vector. The development of pEXC-T offers a convenient technique for the preparations of recombinant proteins to be used in structure/function studies, or as diagnostic markers and medicinal proteins.