Co-workers: Miss Mafalda Almeida, Dr.Burcu Anil Kirmizitas, Dr.Emma Carter, Dr.Heather Coker, Dr.Sarah Cooper, Dr.Michal Gdula, Mr.Jonathan Godwin, Dr.Benoit Moindrot, Dr.Tatyana Nesterova, Ms.Greta Pintacuda, Miss Chloe Roustan, Dr. Guifeng Wei, Miss Tianyi Zhang
Work in the lab centres on understanding the molecular mechanism of X chromosome inactivation, the process mammals use to equalise levels of expression of genes on the X chromosome in females relative to males. X inactivation is initiated by expression of a non-coding RNA, Xist, that coats the chromosome from which it is transcribed, bringing about chromatin modifications that in turn lead to heritable gene silencing. We are interested in how X inactivation is regulated in early development, how X chromosome silencing is established and maintained, and how specific pluripotent lineages can reverse stable silencing of the inactive X.
To address these questions we are combining genetic, cell biological, biochemical and embryology approaches to analyse the role of epigenetic mechanisms such as DNA methylation, RNAi, histone tail modifications, variant histones and chromosome organisation. A central strategy for future work is to identify novel factors involved in epigenetic regulation using both RNAi based loss of function screens and biochemical screens carried out using as bait, factors defined in work to date. Through studying epigenetic mechanisms in X inactivation we aim to better understand their wider role in regulating the genome during differentiation and development.
- Elderkin, S., Maertens, G.N., Endoh, M., Mallery, D.L., Morrice, N., Koseki, H., Peters, G., Brockdorff, N., and Hiom, K. (2007) A phosphorylated form of Mel-18 targets the Ring1B histone H2A ubiquitin ligase to chromatin. Molecular Cell 28 107-120
- Gendrel, A.V., Apedaile, A., Coker, H., Termanis, A., Zvetkova, I., Godwin, J., Tang, Y.A., Huntley. D., Montana, G., Taylor, S., Giannoulatou, E., Heard, E., Stancheva, I., Brockdorff, N. (2012) Smchd1-dependent and -independent pathways determine developmental dynamics of CpG island methylation on the inactive X chromosome. Dev Cell 23 265-279
- Tavares, L., Dimitrova, E., Oxley, D., Webster, J., Poot, R., Demmers, J., Bezstarosti, K., Taylor, S., Ura, H., Koide, H., Wutz, A., Vidal, M., Elderkin, S., Brockdorff, N. (2012) RYBP-PRC1 complexes mediate H2A ubiquitylation at polycomb target sites independently of PRC2 and H3K27me3. Cell 148 664-678
- Cooper, S., Dienstbier, M., Hassan, R., Schermelleh, L., Sharif, J., Blackledge, N.P., De Marco, V., Elderkin, S., Koseki, H., Klose, R., Heger, A., Brockdorff, N. (2014) Targeting Polycomb to Pericentric Heterochromatin in Embryonic Stem Cells Reveals a Role for H2AK119u1 in PRC2 Recruitment. Cell Reports 7 1456–1470
- Moindrot, B., Cerase, A., Coker, H., Masui, O., Grijzenhout, A., Pintacuda, G., Schermelleh, L., Nesterova, T.B., Brockdorff, N. (2015) A Pooled shRNA Screen Identifies Rbm15, Spen, and Wtap as Factors Required for Xist RNA-Mediated Silencing. Cell Reports 12 562–572
Figure 1: An X;4 translocation chromosome shown at metaphase in which the X component is inactive and on which histone H3 is methylated at lysine 27 (H3K27), and the chromosome 4 component is active with histone H4 being highly acetylated (acH4)
Figure 2: An XX female blastocyst stained for the polycomb repressor protein Eed (green) and the pluripotency marker Oct4, delineating cells of the inner cell mass (red). Foci of Eed staining mark the inactive X chromosome. Western analysis of histones from normal and mutant ES cells demonstrate that the complex containing Eed protein is required for methylation of H3K27 (meK27), but not for histone H2A ubiquitylation (uH2A) which is catalysed by a different polycomb repressor complex
Figure 3: E6.5 mouse embryos with a GFP transgene on the paternal X chromosome illustrate imprinted X inactivation of the paternal X in extraembryonic lineages (left panels, non-green cells). Wholemount RNA FISH reveals Xist RNA domains in an E6.5 XX embryo (central panel). Expanded views illustrate cells in the embryonic and extraembyonic tissues, all of which show Xist RNA domains
Graduate Student and Postdoctoral Positions: Enquiries with CV welcome