NUCLEOSIDE DIPHOSPHATE KINASE FROM THE PARASITIC NEMATODE BRUGIA-MALAYI

Using a reverse transcription-polymerase chain reaction (RT-PCR) proce dure that exploited the presence of a conserved 22-nucleotide spliced leader (SL) sequence that is trans-spliced to the 5' end of nematode t ranscripts, a novel Brugia malayi (Bm) infective-stage SL cDNA express ion library was constructed and characterized. The library was immunos creened with rabbit anti-infective-stage antibodies (Ab) and an immuno dominant clone, BmG4-7, was identified and characterized. BmG4-7 conta ined a full-length cDNA that had significant sequence similarity to nu cleoside diphosphate kinase (NDK)-encoding sequences reported from a n umber of species, including Drosophila melanogaster and humans, BmNDK was found to be constitutively transcribed during all stages of parasi te development. An anti-BmNDK Ab was used to immunostain a Western blo t of extracts from adult and larval parasites. The Ab specifically rec ognized a 17.5-kDa molecule in all of the parasite extracts. Molecular modeling of the BmNDK showed several regions surrounding the conserve d catalytic site that may be important in the design of drugs specific for the disruption of NTP synthesis in filarial parasites.