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. Author manuscript; available in PMC: 2009 May 18.
Published in final edited form as: Adv Enzyme Regul. 2007 Mar 23;47:242–250. doi: 10.1016/j.advenzreg.2006.12.014

Fig. 1. Levels of nuclear organization.

Fig. 1

The linear placement of DNA-regulatory elements in gene promoters constitutes the primary level of nuclear organization. The distance between these regulatory sites is intricately regulated by the packaging of DNA into nucleosomes and higher order chromatin structures (left, upper panel). Scaffolding nuclear proteins, such as RUNX, provide structural platforms for the assembly of multiprotein supercomplexes to facilitate the combinatorial control of gene expression (left, bottom panel). Genes and macromolecular regulatory complexes together give rise to dynamic nuclear microenvironments in the nucleus. RUNX bodies are nuclear microenvironments that contain various co-regulatory proteins that are involved in gene activation, as well as repression, chromatin remodeling and cellular signaling (immunofluorescence images on the right, shaded yellow). RUNX was visualized using the Alexa 488 secondary antibody in all images and the proteins were detected using Alexa 568 fluorochrome-conjugated secondary antibodies, as indicated.