UMMS Affiliation

Department of Neurology; Lawrence Lab

Publication Date


Document Type



Cell Biology | Developmental Biology | Genetics and Genomics | Molecular Biology


XIST RNA triggers the transformation of an active X chromosome into a condensed, inactive Barr body and therefore provides a unique window into transitions of higher-order chromosome architecture. Despite recent progress, how XIST RNA localizes and interacts with the X chromosome remains poorly understood. Genetic engineering of XIST into a trisomic autosome demonstrates remarkable capacity of XIST RNA to localize and comprehensively silence that autosome. Thus, XIST does not require X chromosome-specific sequences but operates on mechanisms available genome-wide. Prior results suggested XIST localization is controlled by attachment to the insoluble nuclear scaffold. Our recent work affirms that scaffold attachment factor A (SAF-A) is involved in anchoring XIST, but argues against the view that SAF-A provides a unimolecular bridge between RNA and the chromosome. Rather, we suggest that a complex meshwork of architectural proteins interact with XIST RNA. Parallel work studying the territory of actively transcribed chromosomes suggests that repeat-rich RNA 'coats' euchromatin and may impact chromosome architecture in a manner opposite of XIST A model is discussed whereby RNA may not just recruit histone modifications, but more directly impact higher-order chromatin condensation via interaction with architectural proteins of the nucleus.This article is part of the themed issue 'X-chromosome inactivation: a tribute to Mary Lyon'.


SAF-A, X-inactivation, XIST, nuclear matrix, nuclear scaffold

Rights and Permissions

© 2017 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License, which permits unrestricted use, provided the original author and source are credited.

DOI of Published Version



Philos Trans R Soc Lond B Biol Sci. 2017 Nov 5;372(1733). pii: 20160360. doi: 10.1098/rstb.2016.0360. Link to article on publisher's site

Journal/Book/Conference Title

Philosophical transactions of the Royal Society of London. Series B, Biological sciences

Related Resources

Link to Article in PubMed

PubMed ID


Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.