Characterization and immunolocalization of mutated ornithine decarboxylase antizyme from Angiostrongylus cantonensis

Ornithine decarboxylase antizyme (OAZ), a prominent regulator of cell proliferation, DNA/RNA transformation and tumorigenesis, can bind to ornithine decarboxylase (ODC) and facilitate its degradation. Expression of OAZ requires a unique ribosomal frame shift that is regulated by levels of polyamine in the cell. In this study, we cloned an OAZ gene with the +1 ribosomal frame-shift from a fourth-stage larvae cDNA library of Angiostrongylus cantonensis. We removed one nucleotide to express the gene without polyamine. The sequence analysis showed that the deleted-mutation ornithine decarboxylase antizyme (DM-AcOAZ) contained a conservative domain related to other species OAZ. Quantitative real-time PCR revealed that DM-AcOAZ was expressed in L3 and L4 stages and adult female worms. More notably the expression level is the highest in the adult female stage. Immunohistochemical studies indicated that DM-AcOAZ was specifically localized in the uterus, oocyte and intestine in adult female worms. MTT assays showed that in DM-AcOAZ transfected HeLa cells, cell proliferation is inhibited. In conclusion, DM-AcOAZ may be a female-enriched protein and may involved in the cell proliferation in A. cantonensis.