Assignment1 of fibulin-5 (FBLN5) to human chromosome 14q31 by in situ hybridization and radiation hybrid mapping

We recently reported the cloning and expression pattern of the rat embryonic vascular EGF repeat-containing (EVEC) cDNA (Kowal et al., 1999), the rat homologue of human fibulin-5 (AJ133490; FBLN5). FBLN5 encodes a 448 amino acid protein characterized by the presence of six EGF-like repeats of a subtype predicted to bind Ca++. The predicted structure is most related to the FBNL/S1-5/fibulin-4 and H411/UPH1/ fibulin-3 gene products sharing 40–50% amino acid identity. FBNL has been demonstrated to stimulate DNA synthesis when expressed in quiescent fibroblasts (Lecka-Czernik et al., 1995 ). All three related proteins are closely related to the extracellular matrix proteins, fibulin-1 and -2, which are involved in epithelial to mesenchymal transformations during cardiovascular development (Zhang et al., 1995; Reinhardt et al., 1996). FBNL5/EVEC is expressed during embryogenesis in a variety of mesodermal derivatives, most predominantly in the developing arterial vasculature (Kowal et al., 1999). The level of FBLN5 expression is dramatically reduced in adult arteries, except in the uterus, but is reactivated in the arterial lesions of a mouse model of atherosclerosis and a rat model of neointimal proliferation. These data suggest a possible role of FBNL5 in the regulation of vascular smooth muscle cell proliferation and phenotype. We employed FISH and radiation hybrid mapping to precisely localize the human FBLN5 gene to chromosome 14q31. Materials and methods