Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Article
  • Published:

Human inactive X chromosome is compacted through a PRC2-independent SMCHD1-HBiX1 pathway

Abstract

Human inactive X chromosome (Xi) forms a compact structure called the Barr body, which is enriched in repressive histone modifications such as trimethylation of histone H3 Lys9 (H3K9me3) and Lys27 (H3K27me3). These two histone marks are distributed in distinct domains, and X-inactive specific transcript (XIST) preferentially colocalizes with H3K27me3 domains. Here we show that Xi compaction requires HBiX1, a heterochromatin protein 1 (HP1)–binding protein, and structural maintenance of chromosomes hinge domain–containing protein 1 (SMCHD1), both of which are enriched throughout the Xi chromosome. HBiX1 localization to H3K9me3 and XIST-associated H3K27me3 (XIST-H3K27me3) domains was mediated through interactions with HP1 and SMCHD1, respectively. Furthermore, HBiX1 was required for SMCHD1 localization to H3K9me3 domains. Depletion of HBiX1 or SMCHD1, but not Polycomb repressive complex 2 (PRC2), resulted in Xi decompaction, similarly to XIST depletion. Thus, the molecular network involving HBiX1 and SMCHD1 links the H3K9me3 and XIST-H3K27me3 domains to organize the compact Xi structure.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Figure 1: HBiX1 interacts with HP1 and SMCHD1.
Figure 2: HBiX1 and SMCHD1 affect the distribution of H3K9me3 on Xi in interphase.
Figure 3: HBiX1 and SMCHD1 are involved in Xi chromosome compaction.
Figure 4: Localization of HBiX1 and SMCHD1 on Xi.
Figure 5: Localization of XIST on Xi.
Figure 6: Summary and model of the organization of the human Xi.

Similar content being viewed by others

Accession codes

Primary accessions

DDBJ/GenBank/EMBL

Referenced accessions

NCBI Reference Sequence

References

  1. Heitz, E. Das Heterochromatin der Moose. Jahrb. Wiss. Bot. 69, 762–818 (1928).

    Google Scholar 

  2. Trojer, P. & Reinberg, D. Facultative heterochromatin: is there a distinctive molecular signature? Mol. Cell 28, 1–13 (2007).

    Article  CAS  Google Scholar 

  3. Barr, M.L. & Bertram, E. A morphological distinction between neurones of the male and female, and the behaviour of the nucleolar satellite during accelerated nucleoprotein synthesis. Nature 163, 676–677 (1949).

    Article  CAS  Google Scholar 

  4. Ohno, S., Kaplan, W.D. & Kinosita, R. Formation of the sex chromatin by a single X-chromosome in liver cells of Rattus norvegicus. Exp. Cell Res. 18, 415–418 (1959).

    Article  CAS  Google Scholar 

  5. Rego, A., Sinclair, P.B., Tao, W., Kireev, I. & Belmont, A.S. The facultative heterochromatin of the inactive X chromosome has a distinctive condensed ultrastructure. J. Cell Sci. 121, 1119–1127 (2008).

    Article  CAS  Google Scholar 

  6. Lyon, M.F. Gene action in the X-chromosome of the mouse (Mus musculus L.). Nature 190, 372–373 (1961).

    Article  CAS  Google Scholar 

  7. Chow, J. & Heard, E. X inactivation and the complexities of silencing a sex chromosome. Curr. Opin. Cell Biol. 21, 359–366 (2009).

    Article  CAS  Google Scholar 

  8. Lee, J.T. Gracefully ageing at 50, X-chromosome inactivation becomes a paradigm for RNA and chromatin control. Nat. Rev. Mol. Cell Biol. 12, 815–826 (2011).

    Article  CAS  Google Scholar 

  9. Barakat, T.S., Jonkers, I., Monkhorst, K. & Gribnau, J. X-changing information on X inactivation. Exp. Cell Res. 316, 679–687 (2010).

    Article  CAS  Google Scholar 

  10. Gendrel, A.-V. Smchd1-dependent and -independent pathways determine developmental dynamics of CpG island methylation on the inactive X chromosome. Dev. Cell 23, 265–279 (2012).

    Article  CAS  Google Scholar 

  11. Peters, A.H.F.M. et al. Partitioning and plasticity of repressive histone methylation states in mammalian chromatin. Mol. Cell 12, 1577–1589 (2003).

    Article  CAS  Google Scholar 

  12. Rens, W., Wallduck, M.S., Lovell, F.L., Ferguson-Smith, M.A. & Ferguson-Smith, A.C. Epigenetic modifications on X chromosomes in marsupial and monotreme mammals and implications for evolution of dosage compensation. Proc. Natl. Acad. Sci. USA 107, 17657–17662 (2010).

    Article  CAS  Google Scholar 

  13. Chow, J.C. & Heard, E. Nuclear organization and dosage compensation. Cold Spring Harb. Perspect. Biol. 2, a000604 (2010).

    Article  CAS  Google Scholar 

  14. Chadwick, B.P. & Willard, H.F. Multiple spatially distinct types of facultative heterochromatin on the human inactive X chromosome. Proc. Natl. Acad. Sci. USA 101, 17450–17455 (2004).

    Article  CAS  Google Scholar 

  15. Coppola, G., Pinton, A., Joudrey, E.M., Basrur, P.K. & King, W.A. Spatial distribution of histone isoforms on the bovine active and inactive X chromosomes. Sex Dev. 2, 12–23 (2008).

    Article  CAS  Google Scholar 

  16. Shevchenko, A.I., Pavlova, S.V., Dementyeva, E.V. & Zakian, S.M. Mosaic heterochromatin of the inactive X chromosome in vole Microtus rossiaemeridionalis. Mamm. Genome 20, 644–653 (2009).

    Article  Google Scholar 

  17. Chaumeil, J. et al. Evolution from XIST-independent to XIST-controlled X–chromosome inactivation: epigenetic modifications in distantly related mammals. PLoS ONE 6, e19040 (2011).

    Article  CAS  Google Scholar 

  18. Chadwick, B.P. Variation in Xi chromatin organization and correlation of the H3K27me3 chromatin territories to transcribed sequences by microarray analysis. Chromosoma 116, 147–157 (2007).

    Article  CAS  Google Scholar 

  19. Maison, C. & Almouzni, G. HP1 and the dynamics of heterochromatin maintenance. Nat. Rev. Mol. Cell Biol. 5, 296–304 (2004).

    Article  CAS  Google Scholar 

  20. Nozawa, R.-S. Human POGZ modulates dissociation of HP1α from mitotic chromosome arms through Aurora B activation. Nat. Cell Biol. 12, 719–727 (2010).

    Article  CAS  Google Scholar 

  21. Plath, K. et al. Role of histone H3 lysine 27 methylation in X inactivation. Science 300, 131–135 (2003).

    Article  CAS  Google Scholar 

  22. Silva, J. et al. Establishment of histone H3 methylation on the inactive X chromosome requires transient recruitment of Eed–Enx1 Polycomb group complexes. Dev. Cell 4, 481–495 (2003).

    Article  CAS  Google Scholar 

  23. Blewitt, M.E. et al. SmcHD1, containing a structural-maintenance-of-chromosomes hinge domain, has a critical role in X inactivation. Nat. Genet. 40, 663–669 (2008).

    Article  CAS  Google Scholar 

  24. Margueron, R. & Reinberg, D. The Polycomb complex PRC2 and its mark in life. Nature 469, 343–349 (2011).

    Article  CAS  Google Scholar 

  25. Brown, C.J. et al. A gene from the region of the human X inactivation centre is expressed exclusively from the inactive X chromosome. Nature 349, 38–44 (1991).

    Article  CAS  Google Scholar 

  26. Brown, C.J. et al. The human XIST gene: analysis of a 17-kb inactive X-specific RNA that contains conserved repeats and is highly localized within the nucleus. Cell 71, 527–542 (1992).

    Article  CAS  Google Scholar 

  27. Clemson, C.M., McNeil, J.A., Willard, H.F. & Lawrence, J.B. XIST RNA paints the inactive X chromosome at interphase: evidence for a novel RNA involved in nuclear/chromosome structure. J. Cell Biol. 132, 259–275 (1996).

    Article  CAS  Google Scholar 

  28. Teller, K. et al. A top-down analysis of Xa- and Xi-territories reveals differences of higher order structure at ≥20 Mb genomic length scales. Nucleus 2, 465–477 (2011).

    Article  Google Scholar 

  29. Iyer, L.M., Abhiman, S. & Aravind, L. MutL homologs in restriction-modification systems and the origin of eukaryotic MORC ATPases. Biol. Direct 3, 8 (2008).

    Article  Google Scholar 

  30. Moissiard, G. et al. MORC-family ATPases required for heterochromatin condensation and gene silencing. Science 336, 1448–1451 (2012).

    Article  CAS  Google Scholar 

  31. Lorković, Z.J., Naumann, U., Matzke, A.J.M. & Matzke, M. Involvement of a GHKL ATPase in RNA-directed DNA methylation in Arabidopsis thaliana. Curr. Biol. 22, 933–938 (2012).

    Article  Google Scholar 

  32. Kanno, T. et al. A structural-maintenance-of-chromosomes hinge domain–containing protein is required for RNA-directed DNA methylation. Nat. Genet. 40, 670–675 (2008).

    Article  CAS  Google Scholar 

  33. Splinter, E. et al. The inactive X chromosome adopts a unique three-dimensional conformation that is dependent on Xist RNA. Genes Dev. 25, 1371–1383 (2011).

    Article  CAS  Google Scholar 

  34. Csankovszki, G., Nagy, A. & Jaenisch, R. Synergism of Xist RNA, DNA methylation, and histone hypoacetylation in maintaining X chromosome inactivation. J. Cell Biol. 153, 773–784 (2001).

    Article  CAS  Google Scholar 

  35. Csankovszki, G., Panning, B., Bates, B., Pehrson, J.R. & Jaenisch, R. Conditional deletion of Xist disrupts histone macroH2A localization but not maintenance of X inactivation. Nat. Genet. 22, 323–324 (1999).

    Article  CAS  Google Scholar 

  36. Wutz, A. & Jaenisch, R. A shift from reversible to irreversible X inactivation is triggered during ES cell differentiation. Mol. Cell 5, 695–705 (2000).

    Article  CAS  Google Scholar 

  37. Hiratani, I. et al. Genome-wide dynamics of replication timing revealed by in vitro models of mouse embryogenesis. Genome Res. 20, 155–169 (2010).

    Article  CAS  Google Scholar 

  38. Heard, E. & Disteche, C.M. Dosage compensation in mammals: fine-tuning the expression of the X chromosome. Genes Dev. 20, 1848–1867 (2006).

    Article  CAS  Google Scholar 

  39. Gilbert, D.M. et al. Space and time in the nucleus: developmental control of replication timing and chromosome architecture. Cold Spring Harb. Symp. Quant. Biol. 75, 143–153 (2010).

    Article  CAS  Google Scholar 

  40. Ando, S., Yang, H., Nozaki, N., Okazaki, T. & Yoda, K. CENP-A, -B, and -C chromatin complex that contains the I-type α-satellite array constitutes the prekinetochore in HeLa cells. Mol. Cell Biol. 22, 2229–2241 (2002).

    Article  CAS  Google Scholar 

  41. Hayashi-Takanaka, Y. et al. Tracking epigenetic histone modifications in single cells using Fab-based live endogenous modification labeling. Nucleic Acids Res. 39, 6475–6488 (2011).

    Article  CAS  Google Scholar 

  42. Obuse, C. et al. A conserved Mis12 centromere complex is linked to heterochromatic HP1 and outer kinetochore protein Zwint-1. Nat. Cell Biol. 6, 1135–1141 (2004).

    Article  CAS  Google Scholar 

  43. Kimura, H., Hayashi-Takanaka, Y., Goto, Y., Takizawa, N. & Nozaki, N. The organization of histone H3 modifications as revealed by a panel of specific monoclonal antibodies. Cell Struct. Funct. 33, 61–73 (2008).

    Article  CAS  Google Scholar 

  44. Li, H. & Durbin, R. Fast and accurate short read alignment with Burrows-Wheeler transform. Bioinformatics 25, 1754–1760 (2009).

    Article  CAS  Google Scholar 

  45. Li, H. et al. The Sequence Alignment/Map format and SAMtools. Bioinformatics 25, 2078–2079 (2009).

    Article  Google Scholar 

Download references

Acknowledgements

We thank I. Hiratani, J. Nakayama and D.B. Goto for comments; Y. Hayashi-Takanaka (Osaka University) for the fluorescently labeled antibodies to histones; Y. Ohkubo for cloning the XIST gene; Y. Ohkawa for advice on ChIP-seq; and E. Ono and A. Tokushima for administrative assistance. R.-S.N. was supported by the Japan Society for the Promotion of Science (JSPS) Research Fellowships for Young Scientists (09J01447). This work was supported by the Japanese Ministry of Education, Culture, Sports, Science and Technology (20114006 to C.O. and K.N.), JSPS (24370071 to C.O. and 22710180 to K.N.) and Matrix Science KK (C.O.).

Author information

Authors and Affiliations

Authors

Contributions

R.-S.N. and K.-T.I. performed most of the experiments. K.N. performed the bioinformatics analysis. S.S. operated the Illumina GAIIx. N.S. performed MS. N.N. and H.K. raised antibodies. T.S. performed northern blotting and some RNA FISH experiments. C.O. conceived the study. C.O., K.N. and H.K. wrote the manuscript.

Corresponding author

Correspondence to Chikashi Obuse.

Ethics declarations

Competing interests

N. Nozaki is a founder of the MAB Institute, Inc., which produces the antibodies to H3K9me3 and H3K27me3 used in this study.

Supplementary information

Supplementary Text and Figures

Supplementary Figures 1–6, Supplementary Table 1 and Supplementary Notes 1–3 (PDF 9534 kb)

Rights and permissions

Reprints and permissions

About this article

Cite this article

Nozawa, RS., Nagao, K., Igami, KT. et al. Human inactive X chromosome is compacted through a PRC2-independent SMCHD1-HBiX1 pathway. Nat Struct Mol Biol 20, 566–573 (2013). https://doi.org/10.1038/nsmb.2532

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nsmb.2532

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing