Identification of chicken and C-elegans fibulin-1 homologs and characterization of the C-elegans fibulin-1 gene

Fibulin-1, a member of the emerging family of fibulin proteins, is a compon ent of elastic extracellular matrix fibers, basement membranes and blood. H omologs of fibulin-1 have been described in man, mouse and zebrafish. In th is study, we describe the isolation and sequencing of chicken fibulin-1C an d D cDNA variants. We also describe identification of a C. elegans cDNA enc oding fibulin-1D and cosmids containing the C. elegans fibulin-1 gene. Usin g the cDNA, RT-PCR and computer-based analysis of genomic sequences, the ex on/intron organization of the C. elegans fibulin-1 gene was determined. The C. elegans fibulin-1 gene is located on chromosome IV is approximately 6 k b in length, contains 16 exons and encodes fibulin-1C and D variants. Compa rative analysis of the deduced amino acid sequences of nematode and chicken fibulin-1 variants with other known vertebrate fibulin-1 polypeptides show ed that the number and organization of structural modules are identical. Th e results of this study indicate that the structure of the fibulin-1 protei n has remained highly conserved over a large period of evolution, suggestiv e of functional conservation.