MOLECULAR-CLONING OF THE MICROFIBRILLAR PROTEIN MFAP3 AND ASSIGNMENT OF THE GENE TO HUMAN-CHROMOSOME 5Q32-Q33.2

Microfibrils having a diameter of 10-12 nm, found either in associatio n with elastin or independently, are an important component of the ext racellular matrix of many tissues, but characterization of these micro fibrils is incomplete. To further our understanding of the gene struct ure of proteins composing the microfibrils and to identify their chrom osomal location, we have cloned and characterized another microfibril protein, designated microfibril-associated protein-3 (MFAP3). The huma n gene encoding MFAP3 has a very simple structure, containing only two translated exons encoding a protein of 362 amino acids. Monospecific antibodies prepared against the recombinantly expressed protein reacte d with the microfibrils found in ocular zonules. MFAP3 does not appear to share homology with any other known protein. The gene was found to be located on chromosome 5q32-q33.2, near the locus 5q21-q31 reported for the fibrillin gene, FBN2, which has been linked to congenital con tractural arachnodactyly. MFAP3 is a candidate gene for heritable dise ases affecting microfibrils. (C) 1995 Academic Press, Inc.