THE EXPRESSION OF BIOLOGICALLY-ACTIVE HUMAN P53 IN LEISHMANIA CELLS -A NOVEL EUKARYOTIC SYSTEM TO PRODUCE RECOMBINANT PROTEINS

We have investigated the use of Leishmania cells as a novel eukaryotic expression system for the production of recombinant protein. These ce lls are easy to maintain, requiring no CO2 incubator or shaker, and ca n be grown in standard tissue culture media. Leishmania cells can be r eadily transfected with plasmid DNA by electroporation and transforman ts selected with antibiotic resistance. Recent studies have shown that it is possible to express foreign genes in Leishmania for the purpose of understanding the biology of this protozoan cell, In the present s tudy we report the use of this system as a means of producing a biolog ically functional human p53 protein. The conformation of the p53 prote in is critical for its ability to bind specific DNA sequences. It is d emonstrated that Leishmania-synthesized human p53 is phosphorylated an d can bind specifically to its enhancer DNA sequence, These data demon strate that Leishmania may represent a simple eukaryotic expression sy stem for the production of biologically active recombinant proteins.