In vitro assay for inhibitors of the intron self-splicing reaction in Pneumocystis carinii

摘要

The present invention pertains to an in vitro method for assaying for an inhibitor of the catalytic Group I self-splicing intron reaction in the nuclear rRNA genes of Pheumocystis carinii which comprises the steps of (a) providing a DNA template containing the intron (I) from the 26S rRNA gene in Pneumocystis carinii and a portion of the 5' and 3' flanking exons (E1 and E2, respectively) between nucleotides 1963 and 2267 of 26S rRNA (660 nucleotides of amplified rRNA gene including the group I intron); (b) preparing an RNA precursor by transcription of the DNA template in the presence of labeled nucleoside triphosphates to produce a labeled RNA precursor (E1-I-E2); (c) purifying the RNA precursor; (d) incubating the RNA precursor and the inhibitor in the presence of guanosine triphosphate and magnesium ions; and (e) determining the degree of inhibition by the inhibitor on the intron splicing reaction in the RNA precursor by measuring the amount of labeled splicing intermediates and splicing products.