Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

Significance Polycomb repressor proteins are recruited to the inactive X chromosome in mammals, and this has been attributed to a biochemical interaction between the non–protein-coding RNA X-inactive specific transcript (Xist), which initiates the X inactivation process, and core polycomb subunits. We have studied this using a combination of genome mapping analysis and 3D structured illumination microscopy (3D-SIM) that allows 3D imaging with eightfold volumetric resolution improvement compared with previous state-of-the-art confocal microscopy. Our findings reveal that Xist-mediated recruitment of polycomb repressors does not correlate well with gene silencing and, moreover, that using 3D-SIM, polycomb proteins and Xist RNA show significant spatial separation. These observations challenge prevailing models and prompt a reappraisal of the role of Xist RNA in polycomb recruitment.

Original publication




Journal article


Proceedings of the National Academy of Sciences


Proceedings of the National Academy of Sciences

Publication Date





2235 - 2240