GENOMIC STRUCTURE AND DEVELOPMENTAL EXPRESSION OF THE MOUSE-CELL CYCLE REGULATORY TRANSCRIPTION FACTOR DP1

The E2F/DP family of transcription factors play an important role in t he control of cell cycle progression. By direct regulatory interaction s with the retinoblastoma family of proteins, they integrate extracell ular growth promoting signals impinging on the cyclin and cyclin depen dent kinase complex during the G(1) phase, with cell cycle progression . This is accomplished by direct transcriptional activation of genes r equired for nucleotide biosynthesis and DNA replication in the S phase , In addition, these transcription factors also play a role in the con trol of genes involved in regulating G(1) and S phase progression incl uding, autoregulatory control, as in the case of E2F1 itself, In this report, we describe the characterisation of the genomic locus encoding DP1, a member of this family, The DP1 gene has a TATA-less promoter a nd transcription initiates at multiple sites. Using transient transfec tion assays we have delineated sequences in the upstream region which have promoter or enhancer activity. The DP1 gene was localised to mous e chromosome 8 by metaphase chromosome analysis, We describe a dynamic pattern of DP1 expression using in situ hybridisation on cryostat sec tions of mouse embryos at various stages of development and a variable level of expression by Northern blot analysis of RNA from various adu lt tissues.