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An endonuclease/ligase based mutation scanning method especially suited for analysis of neoplastic tissue
Jianmin Huang1, Brian Kirk, Reyna Favis
1Department of Microbiology, Box 62, Hearst Microbiology Research Center, Strang Cancer Prevention Center, Joan and Sanford I Weill Medical College of Cornell University, Room B-406, 1300 York Avenue, New York, NY 10021, USA.
Oncogene
|March 16, 2002
Summary
This study introduces a novel mutation scanning method using Endonuclease V (Endo V) and DNA ligase for detecting cancer gene mutations. The assay is highly sensitive and specific, proving effective for identifying low-frequency and unknown mutations in pooled DNA samples.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- Accurate detection of inherited and sporadic mutations in cancer genes is crucial for clinical decision-making.
- Existing mutation scanning methods may have limitations in sensitivity and specificity, particularly for low-frequency or unknown mutations.
Purpose of the Study:
- To develop and validate a novel mutation scanning method combining Endonuclease V (Endo V) and DNA ligase.
- To assess the sensitivity and specificity of this new assay for detecting various mutations in known cancer genes.
- To compare the performance of the EndoV/Ligase method with automated DNA sequencing for cancer mutation detection.
Main Methods:
- Generation of variant and wild-type PCR amplicons using fluorescently labeled primers, followed by heteroduplexing.
- Cleavage of heteroduplex DNA by thermostable Thermotoga maritima (Tma) Endonuclease V (Endo V) at mismatch sites.
- Resealing of background nicks by Thermus species (Tsp.) AK16D DNA ligase to enhance assay sensitivity and specificity.
- Analysis of fragment mobility on DNA sequencing gels to determine mutation positions.
Main Results:
- The EndoV/Ligase method successfully identified 31/35 point mutations and 8/8 insertions/deletions in genes including p53, VHL, K-ras, APC, BRCA1, and BRCA2.
- The assay demonstrated high sensitivity, detecting K-ras mutations diluted 1:20 with wild-type DNA and p53 mutations in large amplicons.
- The EndoV/Ligase method, when combined with PCR/LDR/Universal array, outperformed automated DNA sequencing in detecting p53 mutations in colon tumors.
- The technique effectively identified unknown p53 mutations in pooled DNA samples and detected low-frequency mutations in tumor DNA.
Conclusions:
- The combined EndoV/Ligase mutation scanning method offers a highly sensitive and specific approach for genetic mutation detection.
- This technique is particularly well-suited for analyzing pooled DNA samples and identifying low-frequency or unknown mutations in cancer-related genes.
- The EndoV/Ligase assay presents a valuable alternative or complementary tool to automated DNA sequencing for comprehensive cancer mutation profiling.