Molecular analysis of the mouse S100A9 gene and evidence that the myeloid specific transcription factor C/EBPepsilon is not required for the regulation of the S100A9/A8 gene expression in neutrophils

The genomic locus of the mouse S100A9 (MRP14) gene, a myeloid expressed gen e belonging to the S100 family, is split in three exons and two introns. In sertions of B1 like and LINE elements as well as several sequence repeat st ructures are scattered over the gene suggesting that this region of the S10 0 gene cluster has been the subject of a high mutational activity in mouse evolution. The insertions may represent molecular footprints of a recently postulated inversion event, which resulted in a rearrangement of the S100 g ene cluster in mouse compared to man. Deletion analysis of the promoter rev eals, that a 1200 bp fragment is able to direct a cell type-specific expres sion of a reporter gene in granulocytic 32D cells. Unexpectedly, the myeloi d-specific transcription factor C/EBPepsilon is not needed for the transcri ptional upregulation of the S100A9 and S100A8 genes in neutrophils. The dat a described here provide further insights into the evolution of the S100 ge ne cluster and into the myeloid-specific regulation of the murine S100A9 ge ne expression. J. Cell. Biochem. 80:606-616, 2001. (C) 2001 Wiley-Liss, Inc .