THROMBIN RECEPTOR POLYMORPHISM IN CHINESE-HAMSTER

We report the existence of a new Chinese hamster thrombin receptor all ele, characterized by an in-frame insertion of three nucleotides at po sition 250 of the published sequence. As a consequence, an additional proline is inserted into a proline-rich region of the extracellular am inoterminal domain of the receptor. A corresponding proline at this po sition is also found in the rat thrombin receptor. A silent base-pair change is found in the cytoplasmic tail of the receptor gene. Single-s trand conformation polymorphism and sequence analysis indicate this ne w receptor allele is present in several cell lines derived from differ ent individual Chinese hamsters. Embryonic CHEF IIC9 cells and primary culture cells are homozygous for this new allele. In contrast, the CC L39 lung fibroblast cell Line is heterozygous for both the new and old alleles. Both alleles are transcribed into mRNA and code for function al receptors. Given the allelic distribution and sequence alignment wi th thrombin receptors from other species, we propose that the new sequ ence represents the actual predominant allele in Chinese hamster. (C) 1995 Academic Press, Inc.