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Updated: May 29, 2026
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Analysis of LINE-1 Retrotransposition at the Single Nucleus Level
Published on: April 23, 2016
Polymerization and nucleic acid-binding properties of human L1 ORF1 protein
Kathryn E Callahan1, Alison B Hickman, Charles E Jones
1The Laboratory of Molecular and Cellular Biology, National Institue of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
Nucleic Acids Research
|September 23, 2011
Summary
Human L1 ORF1p protein polymerizes without nucleic acids, forming an active conformer that binds nucleic acids. This polymerization may explain cis preference in L1 retrotransposition.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- LINE-1 (L1) retrotransposable elements are crucial for genome evolution.
- L1 elements encode ORF1p and ORF2p proteins; ORF2p is the replicase, but ORF1p's function remains elusive.
- Mouse ORF1p binds nucleic acids and exhibits chaperone activity.
Purpose of the Study:
- To investigate the structure and function of human L1 ORF1p.
- To elucidate the role of ORF1p polymerization in L1 retrotransposition.
Main Methods:
- Purification of human L1 ORF1p expressed in insect cells.
- Biochemical assays to study protein polymerization and nucleic acid binding.
- Analysis of ORF1p's effect on mismatched double-stranded DNA.
Main Results:
- Human L1 ORF1p polymerizes in the absence of nucleic acids under specific salt conditions.
- Polymerization is mediated by the C-terminal half of ORF1p.
- Nucleic acids resolve ORF1p polymers into trimers or multimers.
- ORF1p exhibits a biphasic effect on DNA duplexes, protecting and then melting them.
- Polymerization influences ORF1p's interaction with nucleic acids.
Conclusions:
- ORF1p polymerization is a key regulatory mechanism affecting its nucleic acid interactions.
- This polymerization phenomenon may explain the cis preference of L1 retrotransposition.
- Understanding ORF1p polymerization is vital for comprehending L1 element dynamics and genome stability.
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