Time-resolved structured illumination microscopy reveals key principles of Xist RNA spreading

Visualizing Xist RNA dynamics The noncoding RNA Xist, which controls the process of X chromosome inactivation in mammals, accumulates and spreads over the chromosome from which it is transcribed. The underlying basis for this unusual behavior is poorly understood. Using a new imaging approach called RNA-SPLIT for time-resolved analysis of Xist RNA molecules at super-resolution, Rodermund et al. analyzed fundamental parameters of Xist RNA behavior in normal cells and after the perturbation of factors implicated in Xist RNA function. The authors provide new insights into the basis of Xist RNA localization and confinement within the territory of a single X chromosome. Science , abe7500, this issue p. eabe7500