DNA Replication in Cancer Cells

Berlinguer-Palmini, Rolando

July 27, 2021

DNA Replication in Cancer Cells

Super-resolution microscopy helps to understand DNA replication in cancer cells

DNA synthesis can be impeded by collisions between the DNA replication machinery and co-transcriptional R-loops leading to a major source of genomic instability in cancer cells. In this paper we showed that the ATP-dependent chromatin remodelling INO80 complex promotes resolution of R-loops to prevent replication-associated DNA damage in cancer cells.

We use STED super resolution nanoscopy to measure with unprecedented precision colocalization between INO80 and R-loops.

Title image: 3D volume surface model of INO80 (blue) and R-loops (yellow).

Read the full article:

Prendergast L., McClurg U.L., Hristova R., Berlinguer-Palmini R., Greener S., Veitch K., Hernandez I., Pasero P., Rico D., Higgins J.M.G., Gospodinov A. & Papamichos-Chronakis M.:

Resolution of R-loops by INO80 promotes DNA replication and maintains cancer cell proliferation and viability

Nature Communications volume 11, Article number: 4534 (2020)

https://doi.org/10.1038/s41467-020-18306-x

The increased resolution of STED at ~50 nm in our conditions, compared to confocal imaging (~250 nm), allows discrimination between ‘true’ and ‘false’ colocalization events with high level of certainty. Colocalization between INO80 foci and R-loop foci by STED was readily observed, while multiple colocalization events between INO80 and R-loops visualised by confocal were found to be separate, distinct foci when resolved by STED.

We found for all cells analysed, the R-loops colocalized with INO80 were significantly more intense, had greater volume and greater length than their non-colocalizing counterparts. These data suggest that the INO80 complex associates with the largest, most enriched, R-loop domains in the nucleus.