Dataset Information

De novo reconstitution and isolation of nucleosomes using the wheat germ cell-free protein synthesis

ABSTRACT: DNA is packaged with histones and non-histone proteins to form chromatin that impinges on all nuclear processes such as transcription, replication and repair. A complete molecular understanding of these processes requires analysis of chromatin context. In this study, we report a simple and robust system using the wheat cell-free protein synthesis to assemble chromatin. We report two assembly protocols, the post-translational nucleosome assembly (PNAP) and co-translational nucleosome assembly (CNAP), both of which resulted in a native and unmodified form of chromatin. In the PNAP, a mixture of four unpurified core histones and chromatin assembly factors was combined with other components and incubated with DNA. In the CNAP, mRNAs encoding for these proteins were incubated with DNA in the translation mixture, and concomitantly assembled chromatin. Furthermore, we developed a rapid one-step method to isolate the assembled chromatin using divalent cations. Isolated chromatin was assessed for the stoichiometry of histones, nucleosome arrays, supercoiling, and as a substrate for histone modification enzymes. Our methods provide a new avenue to assemble customized chromatin to understand chromatin structure and function.

ORGANISM(S): Drosophila Melanogaster

SUBMITTER: Nobuaki Takemori

PROVIDER: PXD011113 | panorama | Wed Jun 17 00:00:00 BST 2026

REPOSITORIES: PanoramaPublic

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Publications

De novo reconstitution of chromatin using wheat germ cell-free protein synthesis.

Endo Yaeta Y Takemori Nobuaki N Nagy Szilvia K SK Okimune Kei-Ichi KI Kamakaka Rohinton R Onouchi Hitoshi H Takasuka Taichi E TE

FEBS open bio 20210516 6

DNA is packaged with histones to form chromatin that impinges on all nuclear processes, including transcription, replication and repair, in the eukaryotic nucleus. A complete understanding of these molecular processes requires analysis of chromatin context in vitro. Here, Drosophila four core histones were produced in a native and unmodified form using wheat germ cell-free protein synthesis. In the assembly reaction, four unpurified core histones and three chromatin assembly factors (dNAP-1, dAc ...[more]

PMID: 33960726

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Project description:This model is described in the article: Kinetics of histone gene expression during early development of Xenopus laevis. Koster JG, Destrée OH and Westerhoff HV. J Theor Biol. 1988 Nov 21;135(2):139-67. PMID: 3267765 Abstract: Using literature data for transcriptional and translational rate constants, gene copy numbers, DNA concentrations, and stability constants, we have calculated the expected concentrations of histones and histone mRNA during embryogenesis of Xenopus laevis. The results led us to conclude that: (i) for X. laevis the gene copy number of the histone genes is too low to ensure the synthesis of sufficient histones during very early development, inheritance from the oocyte of either histone protein or histone mRNA (but not necessarily both) is necessary; (ii) from the known storage of histones in the oocyte and the rates of histone synthesis determined by Adamson and Woodland (1977), there would be sufficient histones to structure the newly synthesized DNA up to gastrulation but not thereafter (these empirical rates of histone synthesis may be underestimates); (iii) on the other hand, the amount of H3 mRNA recently observed during early embryogenesis (Koster, 1987, Koster et al., 1988) could direct a higher and sufficient synthesis of H3 protein, also after gastrulation. We present a quantitative model that accounts both for the observed H3 mRNA concentration as a function of time during embryogenesis and for the synthesis of sufficient histones to structure the DNA throughout early embryogenesis. The model suggests that X. laevis exhibits a major (i.e. some 14-fold) reduction in transcription of histone genes approximately 11 hours after fertilization. This reduction could be due to a decrease in the number of transcribed histone genes, a decreased rate constant of transcription with continued transcription of all the histone genes, and/or a reduction in the time during the cell cycle in which histone mRNA synthesis takes place. Alternatively, the histone mRNA stability might decrease approximately 16-fold 11 hours after fertilization. This model originates from BioModels Database: A Database of Annotated Published Models. It is copyright (c) 2005-2011 The BioModels.net Team. To the extent possible under law, all copyright and related or neighbouring rights to this encoded model have been dedicated to the public domain worldwide. Please refer to CC0 Public Domain Dedication for more information. In summary, you are entitled to use this encoded model in absolutely any manner you deem suitable, verbatim, or with modification, alone or embedded it in a larger context, redistribute it, commercially or not, in a restricted way or not.. To cite BioModels Database, please use: Li C, Donizelli M, Rodriguez N, Dharuri H, Endler L, Chelliah V, Li L, He E, Henry A, Stefan MI, Snoep JL, Hucka M, Le Novère N, Laibe C (2010) BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models. BMC Syst Biol., 4:92.

Project description:Maintaining the dynamic structure of chromatin is critical for regulating the cellular processes that require access to the DNA template, such as DNA damage repair, transcription, and replication. Histone chaperones and ATP-dependent chromatin remodeling factors facilitate transitions in chromatin structure by assembling and positioning nucleosomes through a variety of enzymatic activities. SMARCAD1 is a unique chromatin remodeler that combines the ATP-dependent ability to exchange histones, with the chaperone-like activity of nucleosome deposition. We have shown previously that phosphorylated SMARCAD1 exhibits reduced binding to nucleosomes. However, it is unknown how phosphorylation affects SMARCAD1’s ability to perform its various enzymatic activities. Here we use mutational analysis, activity assays, and mass spectrometry, to probe SMARCAD1 regulation and to investigate the role of its flexible N-terminal region. We show that phosphorylation affects SMARCAD1 binding to nucleosomes and DNA, as well as ATP hydrolysis and histone exchange. Conversely, we report that phosphorylation is inconsequential for histone binding and nucleosome assembly. In addition, the SMARCAD1 N-terminal region is revealed to be critical for nucleosome assembly and histone exchange. Together, this work examines the intricacies of how phosphorylation governs SMARCAD1 activity and provides insight into its complex regulation and diverse activities.Maintaining the dynamic structure of chromatin is critical for regulating the cellular processes that require access to the DNA template, such as DNA damage repair, transcription, and replication. Histone chaperones and ATP-dependent chromatin remodeling factors facilitate transitions in chromatin structure by assembling and positioning nucleosomes through a variety of enzymatic activities. SMARCAD1 is a unique chromatin remodeler that combines the ATP-dependent ability to exchange histones, with the chaperone-like activity of nucleosome deposition. We have shown previously that phosphorylated SMARCAD1 exhibits reduced binding to nucleosomes. However, it is unknown how phosphorylation affects SMARCAD1’s ability to perform its various enzymatic activities. Here we use mutational analysis, activity assays, and mass spectrometry, to probe SMARCAD1 regulation and to investigate the role of its flexible N-terminal region. We show that phosphorylation affects SMARCAD1 binding to nucleosomes and DNA, as well as ATP hydrolysis and histone exchange. Conversely, we report that phosphorylation is inconsequential for histone binding and nucleosome assembly. In addition, the SMARCAD1 N-terminal region is revealed to be critical for nucleosome assembly and histone exchange. Together, this work examines the intricacies of how phosphorylation governs SMARCAD1 activity and provides insight into its complex regulation and diverse activities.

Dataset Information

De novo reconstitution and isolation of nucleosomes using the wheat germ cell-free protein synthesis

Publications

De novo reconstitution of chromatin using wheat germ cell-free protein synthesis.

Similar Datasets

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