Isolation and Characterization of Mouse Specificity Protein 6 Promoter

Specificity protein 6 (SP6)is a member of the SP/Kruppel-like transcription factor family and plays key roles in tooth development. Tostudy its biological roles, it is important to understand the spatiotemporal regulation of Sp6gene expression. Forthis purpose, we first identified two separate 5\u27 ends of the Sp6cDNA by 5\u27 RACE analysis using mouse mandibular RNA. Next, we isolated mouse genomic DNA fragments covering the Sp6 gene including two putative mouse Sp6 promoter regions and generated a series of luciferase reporter constructs. We confirmed the activity of both promoters by a luciferase assay and found strong second promoter activity in dental epithelial cells. Unexpectedly,we also detected potential third promoter activity in the intron 2 of the Sp6 gene. Last,we also found that bone morphogenetic protein and wingless signals could enhance Sp6promoter activity in dental epithelial cells, suggestingthe regulatory roles of two cytokines in Sp6 gene expression during tooth development. Our findings may shed new light on the regulatory mechanisms of Sp6 gene expression and provide a possible linkage between cytokine regulation of Sp6 expression and inductive epithelial and mesenchymal interactions. Keywords:Gene expressionluciferase assaypromoter activitySp