Structure of the murine tenascin-R gene and functional characterisation of the promoter.

The tenascin-R (TN-R) gene encodes a multidomain extracellular matrix glycoprotein belonging to the tenascin family. It is detectable mainly in oligodendrocytes and neuronal subpopulations of the central nervous system. In this report, we describe the structure of the 5'-region of the mouse TN-R gene and characterise the activity of its promoter. By in silico cloning and genome walking, we have deduced the organisation of the gene and identified the promoter sequence by 5'-RACE technology. TN-R transcripts in adult mouse brain contain non-coding exons 1 and 2 as demonstrated by the reverse transcriptase-polymerase chain reaction. The promoter displays its activity in cultured cells of neural origin, but not in a fibroblast-like cell line or an undifferentiated teratocarcimoma cell line. As for the human and rat genes, the elements required for the full and cell type-specific activity of the promoter are contained in exon 1 and 167 bp upstream of this exon. The mouse TN-R promoter sequence is similar to that of rat and human in that it displays similarly unusual features: it lacks any classical TATA-box or CAAT-box, GC-rich regions or initiator elements. The promoter contains consensus sequences for binding of a variety of transcription factors, notably p53/p73 and glucocorticoid receptors.