Ribozymes are small and versatile nucleic acids that can cleave RNAs at specific sites. These molecules have great potential to be used as effective gene-therapeutic agents. However, because of the limitation for cleavable sequences within the target mRNA, in some cases conventional ribozymes have failed to exhibit precise cleavage specificity. A maxizyme is the dimer of minimized ribozymes (minizymes), which can specifically cleave two distinct target sites. The maxizyme also has an allosteric function in that it can form an active conformation and cleave the two target sites only when it recognizes two distinct target sites. We demonstrated previously that an allosterically controllable maxizyme was a powerful tool in the disruption of an abnormal chimeric RNA (bcr-abl) in cells and in mice. Furthermore, more than five custom-designed maxizymes have clearly demonstrated these allosteric functions in vitro and in vivo. Thus, maxizyme technology is not limited to one specific case, but may have broad general applicability in molecular biology and in molecular gene therapy.
KeywordsVortex Adenosine Electrophoresis MgCl2 Ampicillin
- 2.Gesteland, R. F., Cech, T. R., and Atkins, J. F. (1999) The RNA World, 2nd ed. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY.Google Scholar
- 4.Kawasaki, H., Suyama, E., Iyo, M., and Taira, K. (2003) siRNAs generated by recombinant human Dicer induce specific and significant but target site-independent gene silencing in human cells. EMBO J., in press.Google Scholar
- 5.Krupp, G. and Gaur, R. K. (eds.) (2000) Ribozyme, Biochemistry and Biotechnology. Eaton Publishing Natick, MA.Google Scholar
- 8.Kuwabara, T., Warashina, M., Nakayama, A., Ohkawa, J., and Taira, K. (1999) Novel tRNAVal-heterodimeric maxizymes with high potential as gene-inactivating agents: Simultaneous cleavage at two sites in HIV-1 tat mRNA in cultured cells. Proc. Natl. Acad. Sci. USA 96, 1886–1891.PubMedCrossRefGoogle Scholar
- 10.Tanabe, T., Kuwabara, T., Warashina, M., Tani, K., Taira, K., and Asano, S. (2000) Oncogene inactivation in a mouse model: tissue invasion by leukaemic cells is stalled by loading them with a designer ribozyme. Nature 406, 473,474.Google Scholar
- 11.Surekha, M., Zinged (2001) Cancer genes. Curr. Sci. 81, 5.Google Scholar