biostudies-literatureUnknown14(1)Tee YHDeviations from mirror symmetry in the development of bilateral organisms are common but the mechanisms of initial symmetry breaking are insufficiently understood. The actin cytoskeleton of individual cells self-organises in a chiral manner, but the molecular players involved remain essentially unidentified and the relationship between chirality of an individual cell and cell collectives is unclear. Here, we analysed self-organisation of the chiral actin cytoskeleton in individual cells on circular or elliptical patterns, and collective cell alignment in confined microcultures. Screening based on deep-learning analysis of actin patterns identified actin polymerisation regulators, depletion of which suppresses chirality (mDia1) or reverses chirality direction (profilin1 and CapZβ). The reveNature communications776https://www.ebi.ac.uk/biostudies/studies/S-EPMC9922260biostudies-literatureActin polymerisation and crosslinking drive left-right asymmetry in single cell and cell collectives.PMC9922260Jalal SBarnett SFHYan JShi SGoh WJMogilner AYong XOng HTThiagarajan VTee YHBershadsky ADHu JHuang WLim YABTay IYYKanchanawong PfalseActin polymerisation and crosslinking drive left-right asymmetry in single cell and cell collectives.Deviations from mirror symmetry in the development of bilateral organisms are common but the mechanisms of initial symmetry breaking are insufficiently understood. The actin cytoskeleton of individual cells self-organises in a chiral manner, but the molecular players involved remain essentially unidentified and the relationship between chirality of an individual cell and cell collectives is unclear. Here, we analysed self-organisation of the chiral actin cytoskeleton in individual cells on circular or elliptical patterns, and collective cell alignment in confined microcultures. Screening based on deep-learning analysis of actin patterns identified actin polymerisation regulators, depletion of which suppresses chirality (mDia1) or reverses chirality direction (profilin1 and CapZβ). The reve2023-01-01T00:00:00Z2023 Feb2026-05-28T11:26:07.358Z2025-02-19T03:26:08.937ZS-EPMC99222603677434610.1038/s41467-023-35918-1