PU.1-mediated transcriptional regulation of prophenin-2 in primary bone marrow cells.

Prophenin-2 (PF-2) is a cathelicidin, 97-amino-acid antimicrobial protein stored in neutrophil secondary granules. PF-2 is expressed specifically in porcine immature myeloid cells; however, little is known about its regulation. In this study, we characterized the 5' regulatory regions of the PF-2 gene to understand the molecular mechanisms regulating its expression. Using bioinformatic approaches, site-directed mutagenesis, and transactivation experiments, we found that the PF-2 gene was regulated by transcription factor PU.1. In addition, PF-2 expression also is regulated by the cytokines GM-CSF and IL-3. Taken together, these results identify cis- and trans-acting factors involved in the regulation of PF-2 and clarify mechanisms of cathelidicin gene regulation.