Jerzy Jurka, Jiong Ma, and Sun-Yu Ng 
Genetic Information Research Institute, 1170 Morse Ave., Sunnyvale, CA 94089 
jurka@charon.girinst.org 

Non-LTR retrotransposons, or retroposons integrate at short, consensus-defined DNA targets in mammals in a process mediated by L1 element^1,2. These targets appear to be hot spots for homologous recombination. We have determined that significant recombination occurs only in cells lacking p53 tumor suppressor protein, such as C33A cell line. Co-transfection of p53 gene to C33A inhibited the recombination. We have also studied recombinogenic effects of different mutations within the targets. The results will be presented. We will discuss implications of our research for understanding genomic instability in cancer and germ line cells as well as its potential applications in gene therapy. 

¹Jurka, J. Proc. Natl. Acad. Sci. U.S.A. 94: 1872-1877 (1997). 
²Feng, Q., Moran, J.V., Kazazian, H.H. & Boeke, J.D. Cell 87: 905-916 (1996)