A role for non-coding Tsix transcription in partitioning chromatin domains within the mouse X-inactivation centre.
BACKGROUND
Delimiting distinct chromatin domains is essential for temporal and spatial regulation of gene expression. Within the X-inactivation centre region (Xic), the Xist locus, which triggers X-inactivation, is juxtaposed to a large domain of H3K27 trimethylation (H3K27me3).


RESULTS
We describe here that developmentally regulated transcription of Tsix, a crucial non-coding antisense to Xist, is required to block the spreading of the H3K27me3 domain to the adjacent H3K4me2-rich Xist region. Analyses of a series of distinct Tsix mutations suggest that the underlying mechanism involves the RNA Polymerase II accumulating at the Tsix 3'-end. Furthermore, we report additional unexpected long-range effects of Tsix on the distal sub-region of the Xic, involved in Xic-Xic trans-interactions.


CONCLUSIONS
These data point toward a role for transcription of non-coding RNAs as a developmental strategy for the establishment of functionally distinct domains within the mammalian genome.
Navarro
Pablo
P
Unité de Génétique Moléculaire Murine, URA 2578, Institut Pasteur 75724, Paris Cedex 15, France.
Chantalat
Sophie
S
CEA/Institut de Génomique/Centre National de Génotypage, 2 rue Gaston Crémieux, 91057, Evry Cedex, France.
Foglio
Mario
M
CEA/Institut de Génomique/Centre National de Génotypage, 2 rue Gaston Crémieux, 91057, Evry Cedex, France.
Chureau
Corinne
C
Unité de Génétique Moléculaire Murine, URA 2578, Institut Pasteur 75724, Paris Cedex 15, France.
Vigneau
Sébastien
S
Unité de Génétique Moléculaire Murine, URA 2578, Institut Pasteur 75724, Paris Cedex 15, France.|Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
Clerc
Philippe
P
Unité de Génétique Moléculaire Murine, URA 2578, Institut Pasteur 75724, Paris Cedex 15, France.
Avner
Philip
P
Unité de Génétique Moléculaire Murine, URA 2578, Institut Pasteur 75724, Paris Cedex 15, France.
Rougeulle
Claire
C
Unité de Génétique Moléculaire Murine, URA 2578, Institut Pasteur 75724, Paris Cedex 15, France.|UMR 7216 Epigenetics and Cell Fate, Université Paris-Diderot Paris 7, CNRS, 35 rue Hélène Brion 75205 Paris Cedex 13, France.