In vivo ribozyme targeting of#BETA#APP~+ mRNAs

摘要

In bAlzheimer's disease (AD) and Down's syndrome (DS)patients, posttranscriptional alterations of se-quences encoded by exon 9 and exon 10 of the#beta#-amyloid precursor protein (#beta#APP) mRNA result in mutant proteins (#beta#APP~+) that colocalize with neurofi-brillary tangles and senile plaques. These aberrantmessages may contribute to tbe development of spo-radic or late-onset Alzheimer's disease; thus, eliminat-ing them or attenuating their expression could signif-icantly benefit AD patients. In the present work, self-cleaving hammerhead ribozymes targeted to #beta#APP exon 9 (Rz9) and #beta#APP~+ mutant exon 10 (RzlO) were examined for their ability to distinguish between #beta#APP and #beta#APP~+ mRNA. In transiently transfected A-204 cells, quantitative confocal fluorescence micros-copy showed that Rz9 preferentially lowered endoge-nous #beta#APP. In contrast, in transient cotransfection experiments with #beta#APP~+ mRNAs containing a wild-type exon 9 and mutant exon 10 (#beta#APP-9/#beta#APP-10+ 1), or a mutant exon 9 and wild-type exon 10 (#beta#APP-9+1/ #beta#APP-10) we found that Rz9 and RzlO preferentially reduced #beta#APP~+-mutant exon 10 mRNA in a concentra-tion and a ribozyme-dependent manner.