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Chromosome Replicating Timing Combined with Fluorescent In situ Hybridization
Published on: December 10, 2012
Differential replication timing of X-linked genes measured by a novel method using single-nucleotide primer extension
Z Xiong1, W Tsark, J Singer-Sam
1Molecular Biology Section and Mammalian Genetics Section, Biology Department, Beckman Research Institute of the City of Hope, 1500 East Duarte Road, Duarte, CA 91010, USA.
Nucleic Acids Research
|February 28, 1998
Summary
Researchers developed a novel method to determine allele-specific replication timing by analyzing DNA replication ratios during S phase. This technique revealed synchronous replication for Gabra-6 alleles and differential timing for X-linked genes Pgk-1 and Xist.
Area of Science:
- Genetics
- Molecular Biology
- Epigenetics
Background:
- Allele-specific replication timing is crucial for understanding gene regulation and genome stability.
- Existing methods lack the resolution to analyze replication timing for alleles differing by single base pairs.
Purpose of the Study:
- To develop and validate a novel method for determining allele-specific replication timing.
- To apply this method to analyze the replication timing of X-linked (Pgk-1, Xist) and autosomal (Gabra-6) genes.
Main Methods:
- Developed a single nucleotide primer extension (SNuPE)-based assay to quantify allele ratios.
- Sorted unsynchronized cells by DNA content to represent different S phase stages.
- Used PCR to amplify alleles differing by at least one base pair, followed by SNuPE analysis.
Main Results:
- The autosomal gene Gabra-6 showed synchronous replication of its two alleles.
- The active Pgk-1 allele on the active X chromosome (Xa) replicated earlier than the silent allele on the inactive X chromosome (Xi).
- The expressed Xist allele on the Xi replicated later than the silent allele on the Xa.
Conclusions:
- The developed SNuPE-based method accurately determines allele-specific replication timing.
- Replication timing of X-linked genes is associated with their activity status and X-chromosome inactivation.
- This method provides a powerful tool for studying gene regulation and epigenetic modifications.
