Cloning and Analysis of a Murine PIAS Family Member, PIASγ, in Developing Skin and Neurons

Signal transducer and activator of transcription (STAT) proteins are latent cytoplasmic transcription factors that become activated in response to stimulation by various cytokines. Recently a new family of five structurally related proteins, called PIAS (Protein Inhibitor of Activated STAT) has been identified as potentially important downregulators of this pathway. Members of the PIAS family of STAT inhibitors may play a prominent role in the downregulation of STAT-mediated signaling processes. In this article we describe the isolation of the cDNA and expression of the gene for the murine homologue of the human STAT inhibitor family member PIASgamma. The cDNA for mPIASgamma encodes a protein of 507 amino acids that is highly homologous to the human protein and is expressed in the mouse as early as d 7.5 of gestation. In situ hybridizations of staged mouse embryos localized the transcript for the PIASgamma gene to the limbs, neuroepithelium, and the inner root sheath of the hair follicle, suggesting a role in the development of these structures. Immunostaining studies with a polyclonal antibody (PAb) recognizing human PIASgamma localized the protein in the hair follicle of human scalp hair and in monkey neuronal cells. Thus PIASgamma exhibits a highly selective pattern of expression, suggesting that it modulates the response of cells to developmental cues.