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SpGCF1, a sea urchin embryo DNA-binding protein, exists as five nested variants encoded by a single mRNA
R W Zeller1, J A Coffman, M G Harrington
1Division of Biology, California Institute of Technology, Pasadena 91125, USA.
Developmental Biology
|June 1, 1995
Summary
Researchers identified SpGCF1, a novel sea urchin DNA-binding protein. This protein generates five distinct polypeptides through differential start codon usage, potentially regulating gene transcription.
Area of Science:
- Molecular Biology
- Developmental Biology
- Genetics
Background:
- Gene regulation in Strongylocentrotus purpuratus involves cis-regulatory regions with specific DNA sequences.
- Blastula stage nuclear extracts contain proteins that bind to these regulatory elements.
Purpose of the Study:
- To identify and characterize DNA-binding proteins interacting with C4 sequences in Strongylocentrotus purpuratus.
- To understand the molecular basis of differential protein synthesis from a single gene.
Main Methods:
- Automated affinity chromatography for protein purification.
- Gel mobility shift assays to analyze DNA-protein interactions.
- Deletion analysis to identify the DNA-binding domain.
- In vitro translation and bacterial expression from cDNA clones.
Main Results:
- A novel sea urchin DNA-binding protein, SpGCF1, was purified and its cDNA isolated.
- SpGCF1 exhibits no homology to known proteins in current databases.
- A single SpGCF1 mRNA produces five distinct DNA-binding polypeptides via differential AUG start codon usage.
- These polypeptides differ in their proline-rich N-terminal domains, suggesting varied transcriptional activation potentials.
Conclusions:
- SpGCF1 is a novel DNA-binding protein in sea urchins.
- Differential start codon usage in SpGCF1 mRNA leads to a family of related proteins with potentially distinct regulatory functions.
- The variable proline-rich N-terminal domains suggest a mechanism for fine-tuning gene expression during development.