Although membrane-associated proteins are related to many diseases and are important targets for drug discovery, their expression is often difficult in bacterial hosts such as Escherichia coli. To overcome this limitation, here, we focused on a novel host-vector system in zebrafish for the expression of human protein O-linked mannose beta-1,2-N-acetylglucosaminyltransferase 1 (hPOMGnT1) which is related to muscle-eye-brain disease. For the expression of hPOMGnT1, the vector pZex-EGFP-pXI-hPOMGnT1 was constructed and injected into fertilized eggs. Using this system, we demonstrated that recombinant hPOMGnT1 was successfully expressed in the whole bodies of zebrafish embryos. (c) 2 012, The Society for Biotechnology, Japan. All rights reserved.