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Fibronectin: a versatile gene for a versatile protein
Ciba Foundation Symposium
|January 1, 1984
Summary
Researchers identified a single rat fibronectin gene producing three mRNA variants through alternative splicing. These variants encode fibronectins with distinct protein segments, influencing cell, heparin, and fibrin binding capabilities.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- Fibronectins are crucial extracellular matrix proteins involved in cell adhesion, migration, and wound healing.
- Alternative splicing of fibronectin mRNA leads to protein isoforms with varied functional properties.
Purpose of the Study:
- To isolate and characterize cDNA and genomic clones of rat fibronectins.
- To elucidate the molecular basis of fibronectin heterogeneity arising from alternative splicing.
- To investigate the structure-function relationships of fibronectin's binding domains.
Main Methods:
- Isolation of complementary DNA (cDNA) and genomic clones for rat fibronectins.
- DNA sequencing to determine the amino acid sequences of fibronectin domains.
- Analysis of intron-exon boundaries to understand gene structure.
Main Results:
- A single fibronectin gene generates three distinct mRNA species via alternative splicing at a complex intron-exon boundary.
- The encoded fibronectins differ in the C-terminal heparin-binding domain due to inserted protein segments.
- Amino acid sequences revealed repeating type III homologies in cell- and heparin-binding regions and type I homologies in the fibrin-binding region.
Conclusions:
- The study reveals the genetic basis for fibronectin diversity through alternative splicing.
- Deduced sequences provide insights into the modular structure of fibronectin and its binding domains.
- The findings offer testable hypotheses regarding fibronectin structure-function relationships and gene organization.