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Retroviral gag and DNA endonuclease coding sequences in IgE-binding factor gene
Nature
|November 4, 1985
Summary
Rodent IgE-binding factors (IgE-BF) are hybrid genes. They contain viral DNA sequences from endogenous retroviruses, suggesting recent evolution by gene integration. This finding reveals a novel cellular gene structure.
Area of Science:
- Immunology
- Molecular Biology
- Genetics
Background:
- Immunoglobulin-binding factors regulate B-cell immunoglobulin heavy-chain isotype synthesis.
- Understanding the genetic basis of these factors is crucial for B-cell regulation research.
Purpose of the Study:
- To determine the nucleotide sequence of rodent IgE-binding factors (IgE-BF).
- To investigate the evolutionary origin and structural composition of the IgE-BF gene.
Main Methods:
- Complementary DNA cloning and nucleotide sequencing of rodent IgE-BF.
- Sequence homology analysis comparing IgE-BF with known genetic sequences, including retroviral genes.
Main Results:
- The IgE-BF messenger RNA encodes a 557-amino acid glycoprotein precursor (60K Mr).
- The 3' region of the IgE-BF coding sequence shows 72% DNA homology with Syrian hamster intracisternal A particle (IAP H18) gag and pol genes.
- The IgE-BF polypeptide consists of an IgE-binding domain and retroviral gag and DNA endonuclease-like domains.
Conclusions:
- The rodent IgE-BF gene is a recently evolved hybrid gene, incorporating viral DNA.
- This represents a potential first instance of a cellular gene containing a virus-derived coding sequence.
- The findings offer new insights into gene evolution and the structural basis of immunoglobulin regulation.
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