TY - JOUR T1 - Expression of Olig2 in terminally differentiated eosinophils among leukocytes JF - European Respiratory Journal JO - Eur Respir J VL - 44 IS - Suppl 58 SP - P4062 AU - Sae Mi Hwang AU - Jin Hyun Kang AU - Il Yup Chung Y1 - 2014/09/01 UR - http://erj.ersjournals.com/content/44/Suppl_58/P4062.abstract N2 - Eosinophils are granulocytes that play a role in homeostasis and pathogenesis of heminth infection and allergic diseases. Olig2, a basic helix loop helix transcription factor, plays a key role in cell fate decision of oligodendrocytes and motor neurons. In the present study, we identified OLIG2 as a gene that among leukocytes is expressed exclusively in eosinophils. When cord blood (CB) CD34+ hematopoietic stem cells differentiated toward eosinophils during a 24 day culture period, Olig2 protein was expressed only in CB eosinophils at day 24, a time when these cells were considered fully differentiated and matured, while Olig2 protein was not detected at day 18 or at earlier time points. Olig2 was also selectively and abundantly expressed in eosinophils, but not in neutrophils or mononuclear cells from human peripheral blood, and was expressed in eosinophilic and mast cell lines. When the developing CB eosinophils were transfected with an OLIG2 promoter reporter encompassing 1.1 kb of the proximal promoter region, promoter activity was significantly higher in CB eosinophils at day 24 than in those at day 18. As the gene encoding major basic protein (MBP), an eosinophil marker, was markedly downregulated at the time when Olig2 protein was upregulated, we examined whether Olig2 affected MBP gene expression. Ectopically expressed Olig2 repressed the activity of the MBP promoter reporter, while a mutant form of Olig2 had no effect. Olig2 siRNA partially reversed the Olig2-mediated repressive effect on MBP promoter activity in vitro. Our results suggest a potential regulator of Olig2 that mediates transcription of eosinophil-specific genes. ER -