A single stranded DNA-binding protein, ssCRE-BP/Pur alpha, in rat lung andits increase in allergic airway inflammation

ssCRE-BP/Pur alpha is a single stranded DNA-binding protein and may be invo lved in gene replication and transcription and in the development of morphi ne dependence. We found a ssCRE-BP/Pur alpha (45 kDa) in rat lung that was larger than those (40 kDa) identified in rat and mouse brains and mouse lun g. Immunohistochemistry showed that ssCRE-BP/Pur alpha is primarily distrib uted in the lung epithelium. As allergic inflammation induces various gene expressions, we investigated the changes of Pur alpha during airway inflamm ation. Ovalbumin-sensitized rats were used for inducing allergic airway inf lammation. The expression and DNA-binding activity of 45-kDa ssCRE-BP/Pur a lpha were significantly increased in the sensitized rat lungs 24 hr after a ntigen challenge, but not in those of rats nonsensitized or sensitized with ovalbumin and challenged with saline. Immunohistochemistry and in situ hyb ridization demonstrated that the vascular endothelial cells and numerous in filtrated eosinophils around the airways were stained with anti-Pur alpha a ntibody. These data suggest that rat lung and the eosinophils contain a 45- kDa ssCRE-BP/Pur alpha that is increased when airway inflammation occurs.