title: Roles of RUNX1 and PU.1 in CCR3 Transcription.
abstract: CCR3 is a chemokine receptor that mediates the accumulation of allergic inflammatory cells, including eosinophils and Th2 cells, at inflamed sites. The regulatory sequence of the CCR3 gene, contains two Runt-related transcription factor (RUNX) 1 sites and two PU.1 sites, in addition to a functional GATA site for transactivation of the CCR3 gene. In the present study, we examined the effects of the cis-acting elements of RUNX1 and PU.1 on transcription of the gene in EoL-1 eosinophilic cells and Jurkat T cells, both of which expressed functional surface CCR3 and these two transcription factors. Introduction of RUNX1 siRNA or PU.1 siRNA resulted in a modest decrease in CCR3 reporter activity in both cell types, compared with transfection of GATA-1 siRNA. Cotransfection of the two siRNAs led to inhibition in an additive manner. EMSA analysis showed that RUNX1, in particular, bound to its binding motifs. Mutagenesis analysis revealed that all point mutants lacking RUNX1- and PU.1-binding sites exhibited reduced reporter activities. These results suggest that RUNX1 and PU.1 participate in transcriptional regulation of the CCR3 gene.
authors.affiliation: Department of Bionano Technology, Hanyang University, Ansan 15588, Korea.
authors.forename: Su-Kang
authors.initials: SK
authors.lastname: Kong
authors.affiliation: Department of Bionano Technology, Hanyang University, Ansan 15588, Korea.
authors.forename: Byung Soo
authors.initials: BS
authors.lastname: Kim
authors.affiliation: Department of Bionano Technology, Hanyang University, Ansan 15588, Korea.
authors.forename: Sae Mi
authors.initials: SM
authors.lastname: Hwang
authors.affiliation: Department of Bioscience and Biotechnology and Protein Research Center of GRRC, College of Natural Sciences, Hankuk University of Foreign Studies, Yongin 17035, Korea.
authors.forename: Hyune Hwan
authors.initials: HH
authors.lastname: Lee
authors.affiliation: Department of Bionano Technology, Hanyang University, Ansan 15588, Korea.; Division of Molecular and Life Sciences, College of Science and Technology, Hanyang University, Ansan 15588, Korea.
authors.forename: Il Yup
authors.initials: IY
authors.lastname: Chung
keywords: CCR3; Cis-acting element; PU.1; RUNX1; Transcription factor