Fibronectin: a versatile gene for a versatile protein.
We have isolated cDNA and genomic clones for rat fibronectins. A single gene gives rise to three different mRNA species by alternative splicing at a complex intron-exon boundary within the coding region. The fibronectins encoded by these three mRNAs differ by the insertion of different protein segments in the C-terminal heparin-binding domain. The amino acid sequences of the cell-, heparin- and fibrin-binding domains in the C-terminal third of fibronectin were deduced from the DNA sequences. The cell- and heparin-binding regions each consist of several similar repeating sequences known as type III homologies, while the fibrin-binding region comprises three repeats of a different type (type I homologies). The sequences suggest several hypotheses for the structure-function relationships of these domains of fibronectin; these hypotheses are now being tested. Determination of intron-exon boundaries within the fibronectin gene is beginning to reveal the modular structure of the gene and its relation to the repeating structure of fibronectin.
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002448:Cell Adhesion; D005353:Fibronectins / Q000235:genetics*; D005796:Genes; D006493:Heparin / Q000378:metabolism; D046911:Macromolecular Substances; D008970:Molecular Weight; D011487:Protein Conformation; D012326:RNA Splicing; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats
D005353:Fibronectins; D046911:Macromolecular Substances; D012333:RNA, Messenger; D006493:Heparin