Ribozyme mediated inactivation of the androgen receptor

DETAILED DESCRIPTION The present invention describes inactivation of AR gene expression by engineering hammerhead ribozymes to cleave specific sites in AR mRNA.
The present in vitro studies of hammerhead ribozymes reveal a high efficiency of such cleavage activity.
The hammerhead ribozymes suppress AR mRNA expression in cultured cells.
Included in the present invention are hammerhead ribozymes that can selectively and efficiently degrade human androgen receptor messenger RNA.
Also part of the present invention are expression vectors containing the gene for a ribozyme that, when introduced into a human prostate cancer cell, is capable of abolishing the androgen receptor mediated transactivation of a reporter gene.
Targeting of the ribozyme gene into specific tissues of transgenic mice can be done to produce tissue-specific inactivation of androgen receptor.
Therapeutic use of the ribozymes of the present invention to suppress androgen action in human clinical conditions such as the prostatic hyperplasia may be accomplished in vivo of the present invention.
The following provides three selection criteria in identifying and designing synthetic ribozyme of the present invention: ##STR1## Based on these three selection criteria, the inventors designed three hammerhead ribozymes and tested their effectiveness in the in vitro endonuclease assay.
One of these ribozymes, HR-2 was found to be particularly highly effective in selectively degrading the androgen receptor mRNA.
This androgen receptor degrading ribozyme is more active than all ribozymes reported in the literature.
##STR2## After eliminating sequence regions that can potentially form secondary structures or have significant homology to heterologous mRNAs, the inventors chose three structural domains of the AR mRNA with high AU contents as targets for the hammerhead ribozyme.
Hammerhead ribozymes are composed of two functionally distinct components; (i) the central catalytic core usually containing about 24 nucleotides with a conserved stem loop structure, and (ii) two variable specifier sequences on both 5' and 3' sides of the catalytic core that are complementary to the target RNA