Dynamic Control of Nuclear Receptor Transcription
Animation: Nuclear Receptor and Transcriptional
Complex Cycles

Amy M. Fowler and Elaine T. Alarid^*

Department of Physiology, University of Wisconsin-Madison, 1300 University Avenue, Madison, WI 53706, USA.

Animation. Nuclear receptors are intracellular transcriptional regulators that reside in either the cytoplasm or nucleus in the inactive state. Based on experiments following the dynamics of the glucocorticoid receptor and estrogen receptor (1, 2), this animation shows nuclear estrogen receptor (ER) and its interaction with a short two-nucleosome fragment of chromatin in the absence and presence of estrogen. Gene activation appears to involve cyclical assembly and disassembly of protein complexes on the promoter region of the gene to be expressed. The periodic associations of different combinations of multimolecular complexes on the DNA over time highlight the dynamics underlying transcriptional regulation.

In this animation, the events that occur on the DNA are represented by the ordered recruitment of protein components to a larger macromolecular complex. The names and abbreviations of the various proteins are listed in Table 1, and their sizes in the animation are depicted in proportion to their relative molecular weights. Classes of proteins, such as HATs and HMTs, are maintained in a single color, and switching among individual proteins that belong to the same class is shown by a change in size and shape. Chromatin remodeling is indicated by an alteration in how tightly the DNA is associated with the histones. Posttranslational modification of histones and phosphorylation of RNAPII are indicated by color changes.

Table 1. Proteins involved in the nuclear receptor-chromatin cycles. Not all proteins are shown individually in the animation. Bold entries indicate the general name given for either a multiprotein complex or a class of proteins.

Abbreviation	Name
ER	Estrogen Receptor
hSWI/SNF hBRG1 INI1 hBRM1	ATP-dependent chromatin remodeling complex (shown as SWI/SNF in the animation) Brahma-related gene 1 protein Integrase interactor 1 Brahma protein
HAT p300 GCN5 Tip60 pCAF CBP	Histone acetyltransferase p300 General control positive factor Tat-interacting protein p300/CBP associated factor CREB binding protein
HMT PRMT1 CARM1	Histone methyltransferase Protein arginine methyltransferase Cofactor associated arginine methyltransferase
CoA SRC1 SRC3	Coactivator Steroid receptor coactivator 1 Steroid receptor coactivator 3
TAFII TAFII250 TAFII130	TATA binding protein (TBP)-associated factor TBP-associated factor of 250 kD TBP-associated factor of 130 kD
TBP	TATA box-binding protein
TFIIA	Component of the basal transcription machinery included in RNA polymerase II holoenzyme
RNAPII	RNA polymerase II
E3 ligase E6AP MDM2	E3 ubiquitin ligase (shown as E3 in the animation) Oncoprotein E6-associated protein Murine double minute 2
Mediator Med7 TRAP220	(multiprotein complex) Mediator subunit 7 Thyroid hormone receptor-associated protein of 220 kD
CDK7	Cyclin-dependent kinase 7 (subunit of TFIIH)
Elongator Elp1 Elp3	(multiprotein complex) Elongator protein 1 Elongator protein 3
APIS SUG1	AAA ATPase proteins independent of 20S (19S regulatory component of the proteasome) Suppressor gene 1
HDAC HDAC1 HDAC7	Histone deacetylase Histone deacetylase 1 Histone deacetylase 7
HSP70	Heat shock protein of 70 kD
NuRD	Nucleosome remodeling and histone deactylation (multiprotein complex, 15 subunits)

Two versions of the animation are available: A smaller size file, which is 2,203 kb and opens in a smaller window, or a larger version, which is 7,686 kb and opens in a larger window. Both animations show the same nuclear receptor cycle. Press the start button at the bottom of the QuickTime movie player to start the animation. Press the pause and play button to start and stop the action at any point.

[Access Small Animation] [Access Large Animation]

Technical Details

Format: Quicktime file (mov file)

Size: 2,203 kb (small version) or 7,686 kb (large version)

Requirements: This animation will play with Quicktime (http://www.apple.com/quicktime/download/).

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Corresponding author. E-mail, //alarid{at}physiology.wisc.edu

References