The thrombospondin-4 gene

Thrombospondins are a family of extracellular, adhesive proteins that are w idely expressed in vertebrates. Five distinct gene products, designated thr ombospondin-1 through -4 and cartilage oligomeric matrix protein (COMP), ha ve been identified. With the exception of thrombospondin-4, the structure a nd location of thrombospondin genes have been determined in the human and/o r mouse genomes. In this study, the structure and location of the murine th rombospondin-4 gene and the location of the human thrombospondin-4, gene ar e reported. The murine thrombospondin-4 gene is approximately 4.5 kb in len gth and includes 22 exons, Interspecific backcross analysis of progeny deri ved from matings of (C57BL/6J x Mus spretus)F-1 x C57BL/6J mice indicates t hat the thrombospondin-4 gene is tightly linked to the Dhfr locus on murine Chromosome (Chr) 13. The human gene maps to Chr 5 in band q13 by in situ h ybridization to human metaphase chromosomes. The thrombospondin-4, promoter is similar to promoters of some housekeeping, growth control, and other th rombospondin genes in that it contains multiple GC box sequences and lacks a CAAT box. The presence of multiple E-box sequence motifs is consistent wi th thrombospondin-4 expression in muscle and bone tissue.