A highly efficient system was developed for the expression of foreign genes
in Chlorella ellipsoidea cells. The effect of five promoters on the expres
sion efficiency of beta -glucuronidase (GUS) gene was evaluated by transien
t expression of the UidA gene. Among these promoters, Ubiquitin-Omega was f
ound to be the most efficient and was selected to drive the expression of f
oreign genes in Chlorella cells. A gene encoding the mature rabbit neutroph
il peptide-1 (NP-1) was introduced into the cells. Integration of the gene
for NP-1 into the Chlorella genome was confirmed by PCR and Southern blot a
nalysis. In vitro anti-microbial testes demonstrated the expression of biol
ogically active NP-1 by the transgenic Chlorella cells.