Identification and characterization of a putative homolog of a spliceosome component,precursor RNA processing 3 in Drosophila melanogaster

Nuclear pre-mRNA splicing occurs in a large RNA-protein complex that contains four small nuclear ribonucleoprotein particles (snRNPs) as well as many protein factors. The Precursor RNA processing 3 (Prp3) is a U4/U6-associated splicing factor. A putative homologue of Prp3, which showed a 45% identity to the human Prp3 in an amino acid sequence, was identified in Drosophila melanogaster (dPrp3). A full-length cDNA clone was isolated and sequenced from the embryonic cDNA library. This gene consisted of 2 exons and contained an open-reading frame that encoded 550 amino acid residues. A Northern blot analysis showed that dPrp3 is expressed both maternally and zygotically. Immunostaining revealed that dPrp3 was localized to the nuclei of nurse cells and follicle cells in early embryos, which is consistent with its role as a component of spliceosome.