Polymorphism in the Dirofilaria immitis immunodominant antigen gene

Dg2, a gene encoding a 34 kDa immunodominant antigen of Dirofilaria immitis was cloned and demonstrated to be specifically expressed in the larval sta ge. In this study, a newly constructed genomic DNA library was screened by hybridization with Dg2. One of the resulting positive clones was similar to Dg2 in the structure of its exonic regions but different in number, positi on, size and sequence of introns. This was designated DgK. Full-length cDNA was isolated using the rapid amplification of cDNA ends (RACE) method to s tudy the transcript corresponding to DgK. Sequence analysis revealed that t he mRNA corresponding to DgK is trans-spliced during post-transcriptional p rocessing because the 5' end of the amplified cDNA contains seven nucleotid es of the nematode-spliced leader (SL) sequence.