Repression and activation by multiprotein complexes that alter chromatin structure.
Recent studies have provided strong evidence that macromolecular complexes are used in the cell to remodel chromatin structure during activation and to create an inaccessible structure during repression, Although there is not yet any rigorous demonstration that modification of chromatin structure plays a direct, causal role in either activation or repression, there is sufficient smoke to indicate the presence of a blazing inferno nearby. It is clear that complexes that remodel chromatin are tractable in vitro; hopefully this will allow the establishment of systems that provide a direct analysis of the role that remodeling might play in activation. These studies indicate that establishment of functional systems to corroborate the elegant genetic studies on repression might also be tractable. As the mechanistic effects of these complexes are sorted out, it will become important to understand how the complexes are regulated. In many of the instances discussed above, the genes whose products make up these complexes were identified in genetic screens for effects on developmental processes. This implies a regulation of the activity of these complexes in response to developmental cues and further implies that the work to fully understand these complexes will occupy a generation of scientists.
Kingston
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Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, 02114, USA.
Bunker
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Imbalzano
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D000255:Adenosine Triphosphate / Q000502:physiology; D000818:Animals; D002843:Chromatin / Q000648:ultrastructure*; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins / Q000502:physiology; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000235:genetics; D005656:Fungal Proteins / Q000502:physiology; D005786:Gene Expression Regulation; D046911:Macromolecular Substances; D009687:Nuclear Proteins; D009707:Nucleosomes / Q000502:physiology / Q000648:ultrastructure; D016601:RNA-Binding Proteins; D012097:Repressor Proteins / Q000502:physiology*; D017412:Ribonucleoprotein, U1 Small Nuclear / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D016615:Telomere; D014157:Transcription Factors / Q000502:physiology*; D014158:Transcription, Genetic
C065455:CYC8 protein, S cerevisiae; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D005656:Fungal Proteins; D046911:Macromolecular Substances; D009687:Nuclear Proteins; D009707:Nucleosomes; D016601:RNA-Binding Proteins; D012097:Repressor Proteins; D017412:Ribonucleoprotein, U1 Small Nuclear; C078562:SWI1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C089969:snf protein, Drosophila; D000255:Adenosine Triphosphate