HUMAN TENASCIN-C - IDENTIFICATION OF A NOVEL TYPE-III REPEAT IN ORAL-CANCER AND OF NOVEL SPLICE VARIANTS IN NORMAL, MALIGNANT AND REACTIVE ORAL MUCOSAE

Tenascin-C is a mosaic, linear glycoprotein that is upregulated during many normal and pathological processes involving either cell migratio n or tissue morphogenesis, such as invasion of malignant cells and wou nd healing, Human tenascin-C contains 8 consecutive type III fibronect in (TNCfn) domains that are involved in alternative splicing and poten tially generate a large number of isoforms that code for tenascin-C pr oteins with subtly different functions, Human tenascin-C splice varian ts were investigated by RT-PCR in a range of normal and pathological o val mucosal tissues, A novel, 9th human TNCfn domain involved in alter native splicing was identified, It shares 70% nucleic acid and 55% pro tein sequence homology with chicken TNCfn-ad2. As in avians, this nove l repeat was located between TNCfn-B and TNCfn-ad1 and accordingly was designated human TNCfn-ad2. Human TNCfn-ad2 was detected in only 2 of IO oral cancers, However, TNCfn-ad2 was absent from 40 normal, reacti ve, pre-malignant and other oral mucosal specimens investigated, Previ ous studies have described 8 splice variant transcripts for human tena scin-C. By systematic investigation we identified further novel splice variants for human tenascin-C, Furthermore, our results indicate that many potential splice variants probably do not exist in the tissues i nvestigated, Thus, we have demonstrated that human tenascin-C transcri pts generate a complex but selected repertoire of different alternativ e splice products, (C) 1997 Wiley-Liss, Inc.