MOLECULAR-CLONING OF A NEW ANGIOPOIETINLIKE FACTOR FROM THE HUMAN CORNEA

PURPOSE. To isolate tissue-specific gene products that contribute to c orneal integrity. METHODS. A cDNA library was constructed and differen tially hybridized. Cornea-specific clones were purified and further ch aracterized. RESULTS. In this study cornea-specific gene products were isolated by differential cDNA hybridization. In addition to known cor nea-specific gene products, a transcript was isolated coding for a pro tein homologous to the angiopoietins, a recently described family of ( anti)angiogenic factors. Subsequently, the full cDNA was sequenced, an d the identified open reading frame was named cornea-derived transcrip t 6 (CDT6). Similar to the angiopoietins, CDT6 contains a hydrophobic NH2-terminal sequence, a coiled-coil domain, and a COOH-terminal fibri nogenlike domain. Expression of CDT6 could be detected only in the cor nea and not in several other adult human tissues. Within the cornea, e xpression of CDT6 is confined to the stromal layer. CONCLUSIONS. The h uman cornea shows high-level expression of a gene product homologous t o the (anti)angiogenic factors, the angiopoietins. This homology, toge ther with stromal-specific expression, suggests that this factor may c ontribute to the avascularity of the human cornea.