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Single-stranded DNA binding proteins isolated from mouse brain recognize specific trinucleotide repeat sequences in
H Yano-Yanagisawa1, Y Li, H Wang
1La Jolla Cancer Research Foundation, CA 92037, USA.
Nucleic Acids Research
|July 25, 1995
Summary
Researchers identified two novel trinucleotide repeat-binding proteins (TRIP-1 and TRIP-2) in mouse brains. These proteins specifically bind to (AGC)n repeats, potentially influencing genes with expanded trinucleotide repeats implicated in neurodegenerative diseases.
Area of Science:
- Neuroscience
- Molecular Biology
- Genetics
Background:
- Trinucleotide repeat expansions (e.g., CAGn, CGGn) are linked to hereditary neurodegenerative diseases.
- Single-stranded repeat-binding activity was investigated in mouse tissue extracts.
Purpose of the Study:
- To identify and characterize proteins that bind to single-stranded (AGC)n trinucleotide repeats in mouse brain.
- To understand the role of these proteins in potential neurodegenerative disease mechanisms.
Main Methods:
- Gel-mobility shift assays were used to detect (AGC)n repeat-binding activity.
- DNA affinity chromatography and FPLC were employed for protein purification.
- UV-cross linking confirmed protein-RNA interactions.
Main Results:
- A specific (AGC)n repeat-binding activity was found predominantly in mouse brain extracts.
- Two proteins, TRIP-1 (44 kDa) and TRIP-2 (40 kDa), were purified and identified as the binding proteins.
- TRIP-1 and TRIP-2 bind to specific trinucleotide repeats like (AGC)n, (AGT)n, (GGC)n, and (GGT)n, requiring at least eight repeats.
- Binding activity increased postnatally, plateauing by 3 weeks.
Conclusions:
- TRIP-1 and TRIP-2 are novel trinucleotide repeat-binding proteins primarily found in the brain.
- These proteins may play a role in regulating genes with expanded trinucleotide repeats, potentially contributing to neurodegeneration.