title: Transcriptional regulation and nuclear reprogramming: roles of nuclear actin and actin-binding proteins.
abstract: Proper regulation of transcription is essential for cells to acquire and maintain cell identity. Transcriptional activation plays a central role in gene regulation and can be modulated by introducing transcriptional activators such as transcription factors. Activators act on their specific target genes to induce transcription. Reprogramming experiments have revealed that as cells become differentiated, some genes are highly silenced and even introduction of activators that target these silenced genes does not induce transcription. This can be explained by chromatin-based repression that restricts access of transcriptional activators to silenced genes. Transcriptional activation from these genes can be accomplished by opening chromatin, in addition to providing activators. Once a de novo transcription network is established, cells are differentiated or reprogrammed to a new cell type. Emerging evidence suggests that actin in the nucleus (nuclear actin) and nuclear actin-binding proteins are implicated in these transcriptional regulatory processes. This review summarizes roles of nuclear actin and actin-binding proteins in transcriptional regulation. We also discuss possible functions of nuclear actin during reprogramming in the context of transcription and chromatin remodeling.
authors.affiliation: The Wellcome Trust/Cancer Research UK Gurdon Institute, The Henry Wellcome Building of Cancer and Developmental Biology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK. k.miyamoto@gurdon.cam.ac.uk
authors.forename: Kei
authors.initials: K
authors.lastname: Miyamoto
authors.forename: J B
authors.initials: JB
authors.lastname: Gurdon
mesh_terms: D000199:Actins / Q000378:metabolism*; D000818:Animals; D002454:Cell Differentiation; D002467:Cell Nucleus / Q000378:metabolism*; D065150:Cellular Reprogramming; D042002:Chromatin Assembly and Disassembly; D004331:Drosophila melanogaster; D005786:Gene Expression Regulation; D020868:Gene Silencing; D006801:Humans; D051379:Mice; D008840:Microfilament Proteins / Q000378:metabolism*; D009865:Oocytes / Q000166:cytology; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014981:Xenopus / Q000378:metabolism
chemical_list: D000199:Actins; D008840:Microfilament Proteins