Objective In mammals, gene dosage of X-chromosomal genes is equalized between sexes by random inactivation of either one of the two X chromosomes in female cells. In the initial phase of X chromosome inactivation (XCI), a counting and initiation process determines the number of X chromosomes per nucleus, and elects the future inactive X chromosome (Xi). Xist is an X-encoded gene that plays a crucial role in the XCI process. At the start of XCI Xist expression is up-regulated and Xist RNA accumulates on the future Xi thereby initiating silencing in cis. Recent work performed in my laboratory indicates that the counting and initiation process is directed by a stochastic mechanism, in which each X chromosome has an independent probability to be inactivated. We also found that this probability is determined by the X:ploïdy ratio. These results indicated the presence of at least one X-linked activator of XCI. With a BAC screen we recently identified X-encoded RNF12 to be a dose-dependent activator of XCI. Expression of RNF12 correlates with Xist expression, and a heterozygous deletion of Rnf12 results in a marked loss of XCI in female cells. The presence of a small proportion of cells that still initiate XCI, in Rnf12+/- cells, also indicated that more XCI-activators are involved in XCI. Here, we propose to investigate the molecular mechanism by which RNF12 activates XCI in mouse and human, and to search for additional XCI-activators. We will also attempt to establish the role of different inhibitors of XCI, including CTCF and the pluripotency factors OCT4, SOX2 and NANOG. We anticipate that these studies will significantly advance our understanding of XCI mechanisms, which is highly relevant for a better insight in the manifestation of X-linked diseases that are affected by XCI. Fields of science natural sciencesbiological sciencesgeneticsRNAnatural sciencesbiological scienceszoologymammalogynatural sciencesbiological sciencesgeneticschromosomes Programme(s) FP7-IDEAS-ERC - Specific programme: "Ideas" implementing the Seventh Framework Programme of the European Community for research, technological development and demonstration activities (2007 to 2013) Topic(s) ERC-SG-LS2 - ERC Starting Grant - Genetics,Genomics,Bioinformatics and Systems Biology Call for proposal ERC-2010-StG_20091118 See other projects for this call Funding Scheme ERC-SG - ERC Starting Grant Coordinator ERASMUS UNIVERSITAIR MEDISCH CENTRUM ROTTERDAM Address Dr molewaterplein 40 3015 GD Rotterdam Netherlands See on map Region West-Nederland Zuid-Holland Groot-Rijnmond Activity type Higher or Secondary Education Establishments Administrative Contact Riet Van Zeijl (Ms.) Principal investigator Joost Henk Gribnau (Dr.) Links Contact the organisation Opens in new window Website Opens in new window EU contribution No data Beneficiaries (1) Sort alphabetically Sort by EU Contribution Expand all Collapse all ERASMUS UNIVERSITAIR MEDISCH CENTRUM ROTTERDAM Netherlands EU contribution € 1 500 000,00 Address Dr molewaterplein 40 3015 GD Rotterdam See on map Region West-Nederland Zuid-Holland Groot-Rijnmond Activity type Higher or Secondary Education Establishments Administrative Contact Riet Van Zeijl (Ms.) Principal investigator Joost Henk Gribnau (Dr.) Links Contact the organisation Opens in new window Website Opens in new window Other funding No data
