Q.66 Which one of the following methods can be used for detecting DNA-protein interaction?
- Southern blotting
- In-situ hybridization
- Chromatin immunoprecipitation
- Amplified fragment length polymorphism
DNA-protein interactions drive gene regulation, but which lab technique specifically captures them? This NEET-style MCQ tests your grasp of molecular biology tools.
Correct Answer: Option (C) – Chromatin immunoprecipitation
ChIP directly isolates DNA bound to proteins (like transcription factors) in living cells using antibodies, proving physical interactions genome-wide—ideal for epigenetics and gene control studies.
Detailed Explanation of All Options
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A. Southern blotting
Incorrect. This hybridizes labeled probes to blotted DNA for specific sequences (e.g., gene copy number), not protein binding. No protein detection involved. -
B. In-situ hybridization
Incorrect. ISH localizes RNA/DNA in tissue sections via complementary probes—great for expression patterns, but ignores proteins entirely. -
C. Chromatin immunoprecipitation
Correct. ChIP crosslinks proteins to DNA, immunoprecipitates with specific antibodies, then analyzes bound DNA (qPCR/sequencing). Reveals in vivo interactions like histone modifications or TF binding sites. -
D. Amplified fragment length polymorphism
Incorrect. AFLP is a DNA fingerprinting PCR method for genetic diversity/variation—compares fragment lengths, no protein role.
How ChIP Works (Quick Steps)
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Fix cells (formaldehyde crosslinks protein-DNA).
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Shear chromatin (sonication).
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Immunoprecipitate (anti-protein antibody).
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Reverse crosslinks, analyze DNA.
Method Target Detects Protein-DNA? Southern Blot DNA sequences No In-situ Hybridization Nucleic acids in tissues No ChIP Protein-bound DNA Yes AFLP DNA polymorphisms No Essential for NEET biotech—ChIP powers ChIP-seq revolutionizing genomics!
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