The School of Molecular and Cellular Biology at the University of Illinois at Urbana-Champaign

Our research focuses on basic questions regarding how chromatin folds into interphase and mitotic chromosomes, how chromosomes are organized and move, in some cases over long distances, within interphase nuclei, and how chromosome organization and dynamics impact DNA functions such as transcriptional activation.

We have pioneered methods for visualizing and manipulating engineered chromosome regions to explore these questions. Major findings from our work include demonstrations that transcription of interphase chromosomes typically occurs on a highly condensed template and that gene activation results in long-range large-scale chromatin decondensation involving the extension or uncoiling of large-scale chromatin fibers. We are now using RNAi screening of transgene arrays in Drosophila S2 cells to identify trans factors involved in this decondensation and to test the functional significance of this large-scale chromatin decondensation in modulating transcriptional activation.

More surprisingly, we have also demonstrated directed interphase chromosome movements of up to several microns in several minutes associated with transcription factor tethering or gene activation. We are currently using the movement of Hsp70 genes relative to nuclear speckles in response to heat shock as a model system to investigate this long-range movement.

We have shown that BAC transgenes carrying 100-250 kb mouse or human genomic sequences stably integrated into mammalian chromosomes reproduce gene expression levels within several fold of endogenous gene loci as well as differential large-scale chromatin compaction and targeting to specific nuclear compartments. Using these BAC transgene arrays we are dissecting cis determinants for nuclear targeting of gene loci as well as investigating cis determinants for establishment of chromatin domains with distinct patterns of epigenetic marks and chromatin folding.

Finally, we have begun to apply what we have learned about large-scale chromatin structure and dynamics to develop novel methods for improved transgene expression. Applications of this technology may lead to improved methods for biopharmaceutical drug production, gene therapy, and tissue engineering.

Representative Publications

Publication List (updated last 4/12):

Revisiting higher-order and large-scale chromatin organization. Bian, Q. and A.S. Belmont, Curr Opin Cell Biol. 2012 March 27 [Epub ahead of print]

Insights into interphase large-scale chromatin structure from analysis of engineered chromosome regions. Belmont AS, Hu Y, Sinclair PB, Wu W, Bian Q, Kireev I., Cold Spring Harb Symp Quant Biol. 2011 Apr 5.

Live-cell chromosome dynamics and outcome of X chromosome pairing events during ES cell differentiation, Masui, O., Bonnet, I., Le Baccon, P., Brito, I., Pollex, T., Murphy, N., Hupe, F., Barillot, E., Belmont, A.S., Heard, E., Live-cell chromosome dynamics and outcome of X chromosome pairing events during ES cell differentiation, Cell 145:447-458 (2011)

Hu, Y., Plutz, M., A. S. Belmont, Hsp70 gene-nuclear speckle association is Hsp70 promoter specific, JCB 191:711-719 (2010)

Sinclair, P., Bian, Q., Plutz, M., Heard, E., A.S. Belmont, Dynamic plasticity of large-scalechromatin structure revealed by self-assembly of engineered chromosome regions, JCB 190: 761-776 (2010) (see JCB biobytes Podcast: http://jcb.rupress.org/content/190/5/761/suppl/DC2)

Bian, Q, A.S. Belmont, BAC TG-Embed: one step method for high-level, copy-number-dependent, position-independent transgene expression, Nucleic Acids Res. 38(11):e127 (2010)

Hu, Y., Kireev, I., Plutz, M., Ashourian, N., A.S. Belmont, Large-scale chromatin structure of inducible genes: transcription on a condensed, linear template, J. Cell. Biol. 185: 87-100 (2009)

Kireev, I, Lakonishok, M., Liu, W.,, Joshi, V.N., Powell, R., A.S. Belmont, In vivo immunogold labeling confirms large-scale chromatin folding motifs, Nat Methods 5:311-313 (2008)

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

Chuang, C., Carpenter, A.E., Fuchsova, B., Johnson, T., de Lanerolle, P., Belmont, A.S., Long-range directional movement of an interphase chromosome site. Curr. Biol. 16:825- 831 (2006)

Belmont, A.S., Mitotic chromosome structure and condensation, Curr. Opin. Cell Biol. 18:632-638 (2006)

Complete Publications List