# In silico protein interaction screening uncovers DONSON's role in replication initiation

Article · Lim Y, Tamayo-Orrego L, Schmid E, Tarnauskaite Z, Kochenova OV, Gruar R, Muramatsu S, Lynch L, Schlie AV, Carroll PL, Chistol G, Reijns MAM, Kanemaki MT, Jackson AP, Walter JC

- Archive id: doi:10.1126/science.adi3448
- Published: 2023-09-22
- Venue: Science (New York, N.Y.)
- DOI: https://doi.org/10.1126/science.adi3448
- PMID: 37590370
- PMCID: PMC10801813
- Citations: 127
- Source URL: https://doi.org/10.1126/science.adi3448
- PDF: https://europepmc.org/articles/PMC10801813/pdf
- Provenance: europepmc

## Abstract

CDC45-MCM2-7-GINS (CMG) helicase assembly is the central event in eukaryotic replication initiation. In yeast, a multi-subunit "pre-loading complex" (pre-LC) accompanies GINS to chromatin-bound MCM2-7, leading to CMG formation. Here, we report that DONSON, a metazoan protein mutated in microcephalic primordial dwarfism, is required for CMG assembly in vertebrates. Using AlphaFold to screen for protein-protein interactions followed by experimental validation, we show that DONSON scaffolds a vertebrate pre-LC containing GINS, TOPBP1, and DNA pol ε. Our evidence suggests that DONSON docks the pre-LC onto MCM2-7, delivering GINS to its binding site in CMG. A patient-derived DONSON mutation compromises CMG assembly and recapitulates microcephalic dwarfism in mice. These results unify our understanding of eukaryotic replication initiation, implicate defective CMG assembly in microcephalic dwarfism, and illustrate how in silico protein-protein interaction screening accelerates mechanistic discovery.

_Abstract reproduced under CC-BY (article license as recorded by Europe PMC; abstract reproduced unmodified apart from markup removal)._

Topics: [AI Protein Design & Structure Prediction](https://space-kitty.com/topics/protein-design)

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