Construction of a Recombinant Major Royal Jelly Protein 1 (MRJP1) Expression Vector for Mammary Gland-Specific Expression

Major royal jelly protein 1 (MRJP1, the most abundant protein of honeybee royal jelly) has been recognized as a valuable functional foods and therapeutic protein for human beings. There is great potential using transgenic technology to express recombinant MRJP1 in milk in order to improve the human health conditions. For expression of MRJP1 in milk, mammary gland-specific expression vector (pBC1-MRJP1-NEOr) carrying the expression cassette composed of β-casein promoter, cDNA encoding MRJP1 (with bovine β-casein signal peptide) and a Neor selection marker was constructed, and expressed in human MCF-7 cells. To examine the expression of MRJP1, a His-tag protein cDNA fragments were fused on the 5' end of MRJP1 gene using PCR amplification. This vector was shown to be expressed successfully, thus potentially enabling the generation of transgenic cows to be used as mammary gland bioreactors.