مشخصات پژوهش

Abstract Objective Mammalian cells as the main host for production of human proteins are incapable of complete c-carboxylation of over-expressed Vitamin K Dependent (VKD) proteins. The Drosophila c-glutamyl carboxylase (DcC) has been shown to be more efficient than its human counterpart in c-carboxylation of human substrates, in vitro. Considering the Drosophila c-carboxylase (DcC) efficiency, in comparison with its human counterpart, for recognition and c-carboxylation of a human substrate in vitro, we were determined to study the effect of the DcC on the hFIX expression in a mammalian cell line. With this aim, we examined co-expression of the DcC with the hFIX, in a human cell line. Results While the co-expression of a complete DcC cDNA reduced the hFIX expression, a truncated form of DcC could improve both the expression level (up to 1211 ng/106 cells/ml on the 4th day of post-transfection) and carboxylation of the expressed hFIX, significantly (p \ 0.009). Conclusions Our findings provided evidences for potential of a partial fragment of the DcC for improvement of the c-carboxylation of a human substrate in a mammalian cell. Our experimental data, in accordance with in silico analysis suggested that the DcC C-terminal fragment, with the advantage of a Kozak-like element has the potential of being expressed as a separate internal translation unit, to generate a peptide with appropriate c-carboxylase activity.