Work in the authors&#39; laboratory is supported by a grant from the National Institute of General Medical Sciences (GM41628) and by a grant to the Stowers Institute for Medical Research from the Helen Nelson Medical Research Fund at the Greater Kansas City Community Foundation.

1. Generation and Culture of HEK293 Stable Cell Lines Expressing Full Length or Mutant Versions of FLAG Epitope-tagged Ino80 or Other INO80 Complex Subunits
<ol>
	<li>Clone cDNA encoding full length or mutant human Ino80 ATPase or another INO80 subunit into the mammalian expression vector pcDNA5/FRT with an in-frame, N terminal FLAG epitope tag.</li>
	<li>Confirm the sequence of the inserted cDNAs by DNA sequencing before proceeding.</li>
	<li>To perform the transfection, grow Flp-In HEK293 cells in 10 cm tissue cultur...

<ol>
	<li>Clapier, C. R., Cairns, B. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+biology+of+chromatin+remodeling+complexes,+Annual+Review+of+Biochemistry.">The biology of chromatin remodeling complexes, Annual Review of Biochemistry.</a> 78, 273-304 (2009).</li><li>Szerlong, H., Hinada, K., Viswanathan, R., Erdjument-Bromage, H., Tempst, P., Cairns, B. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+HSA+domain+binds+nuclear+actin-related+proteins+to+regulate+chromatin-remodeling+ATPases.">The HSA domain binds nuclear actin-related proteins to regulate chromatin-remodeling ATPases.</a> Nature Struct. Mol. Biol. 15 (5), 469-476 (2008).</li><li>Shen, X., Mizuguchi, G., Hamiche, A., Wu, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+chromatin+remodelling+complex+involved+in+transcription+and+DNA+processing.">A chromatin remodelling complex involved in transcription and DNA processing.</a> Nature. 406 (6795), 541-544 (2000).</li><li>Shen, X., Ranallo, R., Choi, E., Wu, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Involvement+of+actin-related+proteins+in+ATP-dependent+chromatin+remodelling.">Involvement of actin-related proteins in ATP-dependent chromatin remodelling.</a> Mol. Cell. 12, 147-155 (2003).</li><li>Chen, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Subunit+organization+of+the+human+INO80+chromatin+remodeling+complex:+an+evolutionarily+conserved+core+complex+catalyzes+ATP-dependent+nucleosome+remodeling.">Subunit organization of the human INO80 chromatin remodeling complex: an evolutionarily conserved core complex catalyzes ATP-dependent nucleosome remodeling.</a> Journal of Biological Chemistry. 286 (13), 11283-11289 (2011).</li><li>Sauer, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Site-specific+recombination:+developments+and+applications.">Site-specific recombination: developments and applications.</a> 5 (5), 521-527 (1994).</li><li>Gorman, S., Fox, D. T., Wahl, G. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recombinase-mediated+gene+activation+and+site-specific+integration+in+mammalian+cells.">Recombinase-mediated gene activation and site-specific integration in mammalian cells.</a> Science. 251 (4999), 1351-1355 (1991).</li><li>Jin, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+mammalian+chromatin+remodeling+complex+with+similarities+to+the+yeast+INO80+complex.">A mammalian chromatin remodeling complex with similarities to the yeast INO80 complex.</a> Journal of Biological Chemistry. 280 (50), 41207-41212 (2005).</li><li>Cai, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=YY1+functions+with+INO80+to+activate+transcription.">YY1 functions with INO80 to activate transcription.</a> Nature Structural and Molecular Biology. 14 (9), 872-874 (2007).</li><li>Yao, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Distinct+Modes+of+Regulation+of+the+Uch37+Deubiquitinating+Enzyme+in+the+Proteasome+and+in+the+Ino80+Chromatin-Remodeling+Complex.">Distinct Modes of Regulation of the Uch37 Deubiquitinating Enzyme in the Proteasome and in the Ino80 Chromatin-Remodeling Complex.</a> Mol.Cell. 31 (6), 909-917 (2008).</li><li>Brizzard, B. L., Chubet, R. G., Vizard, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immunoaffinity+purification+of+FLAG+epitope-tagged+bacterial+alkaline+phosphatase+using+a+novel+monoclonal+antibody+and+peptide+elution,+Biotechniques.">Immunoaffinity purification of FLAG epitope-tagged bacterial alkaline phosphatase using a novel monoclonal antibody and peptide elution, Biotechniques.</a> 16 (4), 730-735 (1994).</li><li>Barker, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> At the Bench: A Laboratory Navigator. 10, 207-245 (2005).</li><li>Dignam, J. D., Lebovitz, R. M., Roeder, R. 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The authors declare that they have no competing financial interests.

Structural and functional studies of multi-subunit mammalian chromatin remodeling complexes from higher eukaryotes have been hampered by the difficulty of preparing biochemically useful amounts of such complexes containing mutant subunits or lacking certain subunits altogether. There are a number of technical hurdles: First, genetic manipulation in mammalian cells has been technically challenging and time-consuming. Unlike yeast cells, whose genome can be readily edited and targeted using recombineering techniques, the m...

Evolutionarily conserved SNF2 family chromatin remodeling complexes are key regulators of chromatin organization and DNA accessibility1. These remodeling complexes always include a central SNF2-like ATPase subunit, which, in some cases, assembles with various accessory proteins and forms multi-subunit macro-molecular assemblies. To study the molecular details of the ATP-dependent chromatin remodeling process, it is important to understand the contributions of given subsets of subunits and/or domain structures to activities of the complexes. Such analyses require the ability to generate highly purified mutant complexes that lack particular protein subunits or domain structures.
Previous structure-function studies of ATP-dependent chromatin remodeling complexes have widely focused on the yeast model system due to the superior manipulability of the yeast genome (see, for example, refs1-4). Given the conservation of subunit composition and functionality among orthologous remodeling complexes, studies of the structure and function of yeast remodeling complexes have provided important insights into their counterparts in higher eukaryotes. Nonetheless, appreciable species-specific differences among remodeling complexes do exist, resulting from gain or loss of species-specific subunits, gain or loss of species-specific domains of conserved subunits, and sequence variability within conserved domains of conserved subunits. Such differences can in principle be driven by the need for higher eukaryotic cells to adapt to new molecular and cellular environments. Thus, understanding how subunits of higher eukaryotic remodeling complexes contribute to the nucleosome remodeling process is valuable, because it not only sheds light on basic mechanisms of the ATP-dependent chromatin remodeling process, but also can provide valuable insight into the mechanisms by which chromatin structure and gene expression in higher eukaryotes are regulated.
Thus far, there have been only limited structural and functional studies of multi-subunit mammalian chromatin remodeling complexes, due in part to the difficulties in obtaining biochemically defined chromatin remodeling complexes and subcomplexes. We have partially circumvented these difficulties with the procedures described below, in which immunoaffinity purification is used to prepare intact INO80 or INO80 subcomplexes from human cells stably expressing N-terminally FLAG epitope tagged wild type or mutant versions of Ino805-7 (Figure 1). To obtain intact INO80 complexes from human cells, Flp-mediated recombination is used to generate transgenic HEK293 cell lines stably expressing FLAG epitope tagged cDNAs encoding subunits of the INO80 complex8-10. Because over-expression of INO80 subunits can be somewhat toxic, it is necessary to isolate and maintain clonal cell lines under selective conditions to ensure stable transgene expression during the many passages needed for expansion of large-scale cell cultures. To obtain smaller INO80 subcomplexes that contain only a subset of subunits, we have successfully used two approaches (Figure 2A,B). In the first, we generate HEK293 Flp-In cell lines stably expressing mutant versions of Ino80 that lack domains required for interaction with specific subunits5. Alternatively, siRNA-mediated knockdown is used to deplete the desired subunit from cells expressing an appropriate FLAG-tagged INO80 subunit (unpublished data). Finally, to purify the human INO80 complexes, FLAG agarose based chromatography11 is used to enrich an INO80-containing fraction from nuclear extracts, thereby effectively reducing the presence of contaminating cytosolic proteins in the final fraction containing purified INO80 or INO80 subcomplexes.

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generation and purification of human ino80 chromatin remodeling complexes and subcomplexes

INO80 chromatin remodeling complexes regulate nucleosome dynamics and DNA accessibility by catalyzing ATP-dependent nucleosome remodeling. Human INO80 complexes consist of 14 protein subunits including Ino80, a SNF2-like ATPase, which serves both as the catalytic subunit and the scaffold for assembly of the complexes. Functions of the other subunits and the mechanisms by which they contribute to the INO80 complex&#39;s chromatin remodeling activity remain poorly understood, in part due to the challenge of generating INO80 subassemblies in human cells or heterologous expression systems. This JOVE protocol describes a procedure that allows purification of human INO80 chromatin remodeling subcomplexes that are lacking a subunit or a subset of subunits. N-terminally FLAG epitope tagged Ino80 cDNA are stably introduced into human embryonic kidney (HEK) 293 cell lines using Flp-mediated recombination. In the event that a subset of subunits of the INO80 complex is to be deleted, one expresses instead mutant Ino80 proteins that lack the platform needed for assembly of those subunits. In the event an individual subunit is to be depleted, one transfects siRNAs targeting this subunit into an HEK 293 cell line stably expressing FLAG tagged Ino80 ATPase. Nuclear extracts are prepared, and FLAG immunoprecipitation is performed to enrich protein fractions containing Ino80 derivatives. The compositions of purified INO80 subcomplexes can then be analyzed using methods such as immunoblotting, silver staining, and mass spectrometry. The INO80 and INO80 subcomplexes generated according to this protocol can be further analyzed using various biochemical assays, which are described in the accompanying JOVE protocol. The methods described here can be adapted for studies of the structural and functional properties of any mammalian multi-subunit chromatin remodeling and modifying complexes.

Figure 1 shows a flow chart summarizing the procedures used to generate, purify, and characterize human INO80 ATP-dependent chromatin remodeling complexes.
As illustrated in Figures 2 and 3, these procedures enable the generation of both wild type INO80 and INO80 subcomplexes that lack various subunits, thereby enabling subsequent biochemical analyses of the contribution of these missing subunits to INO80&#39;s enzymatic activities. Fi...

Watch this Scientific Journal Video about Generation and Purification of Human INO80 Chromatin Remodeling Complexes and Subcomplexes at JoVE.com

Generation and Purification of Human INO80 Chromatin Remodeling Complexes and Subcomplexes

This protocol describes a procedure for generating and purifying wild type and mutant versions of the human INO80 chromatin remodeling complex. Epitope tagged versions of INO80 subunits are stably expressed in HEK293 cells, and complete complexes and complexes lacking specific sets of subunits are purified by immunoaffinity chromatography.

INO80 chromatin remodeling complexes regulate nucleosome dynamics and DNA accessibility by catalyzing ATP-dependent nucleosome remodeling. Human INO80 ...

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9.7K Görüntüleme.  Stowers Institute for Medical Research.  Bu protokol oluşturulması ve vahşi tip ve insan INO80 kromatin yeniden şekillenme kompleks mutant versiyon saflaştırılması için bir yöntem tarif etmektedir. Epitop INO80 alt birimlerinin versiyonları kararlı biçimde HEK293 hücrelerinde ifade edilir ve alt birimlerinin kümelerini yoksun tam kompleksleri kompleksleri ve bağışıklık yakınlık kromatografisi ile etiketlenmiş. 