THE FOWL ADENOVIRUS TYPE-1 (CELO) VIRUS-ASSOCIATED RNA-ENCODING GENE - A NEW RIBOZYME-EXPRESSION VECTOR

A new system for hammerhead ribozyme (Rz) expression was examined in w hich fowl adenovirus type 1 (CELO) virus-associated RNA (CELO VA RNA) was used as a vector for the incorporation of Rz to target the mRNA of secreted alkaline phosphatase (SEAP) both in vitro and in vivo. The R z gene was integrated into the CELO VA RNA between the internal promot er boxes A and B; apparently this did not interfere with its transcrip tion. Rz integrated into CELO VA RNA and, lacking the viral sequences, exhibited the same activity in vitro. Consequently, CELO VA RNA seque nces did not inhibit the integrated Rz activity in vitro. In vivo expe riments were carried out with human 293 cells by co-transfection with plasmids containing Rz and SEAP. Inhibition of enzyme activity was 50% in 48 h. We conclude that CELO VA RNA may be used for effective expre ssion of hammerhead Rz.