Efficient expression of human α₁-antitrypsin by the caprine β-lactoglobulin promoter in the mouse mammary cell, HC11

Abstract

The configuration of regulatoiy sequence and protein coding sequence, such as the presence of introns, is considered to be a crucial factor in determining the expression level of the protein of interest. As a preliminary step for generating transgenic animals targeting the expression of human apantitrypsin (apAT) to the mammary gland, we evaluated the feasibility of using the regulatory sequence of the caprine p-lactoglobuline gene to drive expression of the human protein from various vector constructs in a mouse mammary cell line, HC11. The 1.6 kb caprine regulatory sequence supported efficient expression of human ct？AT transcript from the vector constructed with the apAT cDNA sequence. The enhancing effect of arAT intronic sequence on the arAT transcription, however, was not observed in the cells transfected with the vector containing the cti-AT genomic DNA. Both the cDNA construct and the genomic construct showed a similar level of expression for the human ai-AT protein, which was secreted as a glycosylated form into the culture media. The results indicate that intronic sequence of human ai-AT is not absolutely required for the efficient expression driven by the caprine regulatory sequence in the mouse mammary cell.