Ten^a, a Drosophila gene related to tenascin, shows selective transcript localization

We report the identification and molecular characterization of ten^a*, a Drosophila gene located at 11A6-9 on the X-chromosome. The deduced protein of 782 amino acids contains eight tenascin-type EGF-like repeats not described in Drosophila before, but lacks the fibronectin type III repeats and the fibrinogen homology present in the vertebrate tenascin molecules. Ten^a codes for a large transcript which exhibits extremely long 5′ and 3′ untranslates regions. Ten^a transcripts show a specific perinuclear localization within cells and are mainly expressed in the central nervous system, in the brain and near muscle attachment sites during embryogenesis. During pupal stages, ten^a is detected in the eye. These expression patterns are reminiscent of those of vertebrate tenascin. Tenascin-type EFG-like sequences are also detected in other loci of Drosophila and in various other organisms, indicating the existence of a family of genes related to tenascin.