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Proux, F.

Publications and source records attributed to Proux, F..

3 recordsLinked to original sources

High-resolution single-molecule replication profiling of the human genome

Despite the considerable progress made in recent years thanks to the rise of long-read sequencing, high-resolution, single molecule (SM)-based replication profiling of large genomes has remained out of reach. Here, we present a replication labelling strategy consisting in repeated pulse-labelling of asynchronously growing cells with the thymidine analogue bromodeoxyuridine (BrdU) that greatly enhances the number of detectable replication tracks. We show that the multipulse BrdU labelling protocol, in association with ForkML, a machine-learning method translating BrdU signals in nanopore reads into oriented and positioned replication forks, enables the establishment of a SM replication map of the entire human genome at kilobase resolution.

genomics↗

FORK-seq: replication landscape of the Saccharomyces cerevisiae genome by nanopore sequencing

Genome replication mapping methods profile cell populations, masking cell-to-cell heterogeneity. Here, we describe FORK-seq, a nanopore sequencing method to map replication of single DNA molecules at 200 nucleotide resolution. By quantifying BrdU incorporation along pulse-chased replication intermediates from Saccharomyces cerevisiae, we orient 58,651 replication tracks reproducing population-based replication directionality profiles and map 4,964 and 4,485 individual initiation and termination events, respectively. Although most events cluster at known origins and fork merging zones, 9% and 18% of initiation and termination events, respectively, occur at many locations previously missed. Thus, FORK-seq reveals the full extent of cell-to-cell heterogeneity in DNA replication.

genomics↗

Mapping DNA replication with nanopore sequencing

We have harnessed nanopore sequencing to study DNA replication genome-wide at the single-molecule level. Using in vitro prepared DNA substrates, we characterized the effect of bromodeoxyuridine (BrdU) substitution for thymidine on the MinION nanopore electrical signal. Using a neural-network basecaller trained on yeast DNA containing either BrdU or thymidine, we identified BrdU-labelled tracts in yeast cells synchronously entering S phase in the presence of hydroxyurea and BrdU. As expected, the BrdU-labelled tracts coincided with previously identified early-firing, but not late-firing, replication origins. These results open the way to high-throughput, high-resolution, single-molecule analysis of DNA replication in many experimental systems.

genomics↗