Identification and characterization of human PRICKLE1 and PRICKLE2 genes as well as mouse Prickle1 and Prickle2 genes homologous to Drosophila tissue polarity gene prickle

Drosophila prickle is implicated in tissue polarity or planar polarity. Here, human PRICKLE1 gene corresponding to FLJ31937 cDNA and human PRICKLE2 gene corresponding to DKFZp686D143 cDNA were identified to be homologous to Drosophila prickle gene by using bioinformatics. PRICKLE1 gene was mapped to human chromosome 12p11-q12, and PRICKLE2 gene was mapped to human chromosome 3p14. Mouse Prickle1 and Prickle2 genes were next identified in mouse genome draft sequences NW_000106.1 and NW_000262.1, respectively. Human PRICKLE1, PRICKLE2, Xenopus Prickle, and Drosophila prickle were homologous in the PET domain, three LIM domains, and the C-terminal Prickle homologous (PKH) domain. LMO6 and TESTIN, containing the PET domain and three LIM domains, were found to lack the PKH domain. Therefore, PRICKLE1 and PRICKLE2 rather than LMO6 and TESTIN were found to be human homologs of Drosophila prickle. PRICKLE1 and PRICKLE2 mRNAs were expressed together in brain, eye and testis. PRICKLE1 mRNA was expressed in fetal heart and hematological malignancies, while PRICKLE2 mRNA in fetal brain, adult cartilage, pancreatic islet, gastric cancer with signet-ring cell features, and uterus tumors. Because tissue polarity genes frizzled, dishevelled, flamingo, and Vang are evolutionary and functionary conserved from Drosophila to human, PRICKLE1 and PRICKLE2 might be implicated in the localization of Frizzled and Dishevelled proteins, just like Drosophila prickle. This is the first report on identification and characterization of human PRICKLE1, PRICKLE2, mouse Prickle1, and Prickle2 genes.