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November 13th, 2014

Strand-Specific Analysis Shows Protein Binding at Replication Forks and PCNA Unloading from Lagging Strands when Forks Stall

By Center for Individualized Medicine

Zhiguo Publication

Zhiguo Zhang, Ph.D. and colleagues from the Center for Individualized Medicine, offer a new tool for genomic research, through a new method revealing genome-wide association of proteins with leading and lagging strands of DNA replication forks. This will provide a tool for studying the general replication-related processes and a specific mechanism that makes this possible.

 

Summary of Publication

In eukaryotic cells, DNA replication proceeds with continuous synthesis of leading-strand DNA and discontinuous synthesis of lagging-strand DNA. Here we describe a method, eSPAN (enrichment and sequencing of protein-associated nascent DNA), which reveals the genome-wide association of proteins with leading and lagging strands of DNA replication forks.

Using this approach in budding yeast, we confirm the strand specificities of DNA polymerases delta and epsilon and show that the PCNA clamp is enriched at lagging strands compared with leading-strand replication. Surprisingly, at stalled forks, PCNA is unloaded specifically from lagging strands. PCNA unloading depends on the Elg1-containing alternative RFC complex, ubiquitination of PCNA, and the checkpoint kinases Mec1 and Rad53. Cells deficient in PCNA unloading exhibit increased chromosome breaks.

Our studies provide a tool for studying replication-related processes and reveal a mechanism whereby checkpoint kinases regulate strand-specific unloading of PCNA from stalled replication forks to maintain genome stability.

 

Read the full publication here.

 

 

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Tags: center for individualized medicine, DNA, DNA Sequencing, dna test, DNA Testing, gene sequencing, genetic, Genetics, genome, genome science, Genome Sequencing, Genomic, genomic medicine, genomics, individualized medicine, Individualized Medicine Clinic, IndividualizedMedicine, mayo clinic, personal genomics, personalized care, personalized medicine, predictive medicine, Uncategorized, whole genome sequencing, Zhiguo Zhang

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