An integrated approach to the study of Pirin genes function in eukaryotes

Pirin genes are highly conserved in eukaryotes. Human and plants are the principal organisms in which they are studied. Here is reported the characterization of Arabidopsis Prn genes function during seed germination and programmed cell death (PCD). Among the germination conditions tested, atpirin1 null mutant seeds resulted to be oversensitive to abscissic acid (ABA), whereas atpirin3 seeds disclosed hyposensitivity to this hormone. Notably, ABA in wild type plants regulates the transcription of both pir1 and 3.Quantitative RT-PCR analyses performed on plants and cell cultures confirmed the possible involvement of Prn1 and Prn3 in plant PCD, particularly in the response to DNA damage. Given the elevated similarity between Pirin homologues, it has been investigated the hypothesis of the involvement of the HsPirin gene in apoptosis. In lymphoma lines characterized by an altered expression of Bcl-3, a PIRIN interacting protein, HsPirin resulted to be putatively involved in starvation-induced apoptosis and cell cycle progression following DNA damage. Moreover, HsPirin expression levels seem to provide a parameter for the choice of the appropriate therapy for tumour treatment. Eukaryotes Pirin homologues could have maintained a role in the response to DNA damage and have evolved new functions in processes that are peculiar to each organism.