scholarly journals Specialization of the Chromatin Remodeler RSC to Mobilize Partially-Unwrapped Nucleosomes

2019 ◽  
Author(s):  
Alisha Schlichter ◽  
Margaret M. Kasten ◽  
Timothy J. Parnell ◽  
Bradley R. Cairns

AbstractSWI/SNF-family chromatin remodeling complexes, such as S. cerevisiae RSC, slide and eject nucleosomes to regulate transcription. Within nucleosomes, stiff DNA sequences confer spontaneous partial unwrapping, prompting whether and how SWI/SNF-family remodelers are specialized to remodel partially-unwrapped nucleosomes. RSC1 and RSC2 are orthologs of mammalian PBRM1 (polybromo) which define two separate RSC sub-complexes. Remarkably, in vitro the Rsc1-containing complex remodels partially-unwrapped nucleosomes much better than does the Rsc2-containing complex. Moreover, a rsc1Δ mutation, but not rsc2Δ, is lethal with histone mutations that confer partial unwrapping. Rsc1/2 isoforms both cooperate with the DNA-binding proteins Rsc3/30 and the HMG protein, Hmo1, to remodel partially-unwrapped nucleosomes, but show differential reliance on these factors. Notably, genetic impairment of these factors strongly reduces the expression of genes with wide nucleosome-deficient regions (e.g. ribosomal protein genes), known to harbor partially-unwrapped nucleosomes. Taken together, Rsc1/2 isoforms are specialized through composition and interactions to manage and remodel partially-unwrapped nucleosomes.


eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Alisha Schlichter ◽  
Margaret M Kasten ◽  
Timothy J Parnell ◽  
Bradley R Cairns

SWI/SNF-family chromatin remodeling complexes, such as S. cerevisiae RSC, slide and eject nucleosomes to regulate transcription. Within nucleosomes, stiff DNA sequences confer spontaneous partial unwrapping, prompting whether and how SWI/SNF-family remodelers are specialized to remodel partially-unwrapped nucleosomes. RSC1 and RSC2 are orthologs of mammalian PBRM1 (polybromo) which define two separate RSC sub-complexes. Remarkably, in vitro the Rsc1-containing complex remodels partially-unwrapped nucleosomes much better than does the Rsc2-containing complex. Moreover, a rsc1Δ mutation, but not rsc2Δ, is lethal with histone mutations that confer partial unwrapping. Rsc1/2 isoforms both cooperate with the DNA-binding proteins Rsc3/30 and the HMG protein, Hmo1, to remodel partially-unwrapped nucleosomes, but show differential reliance on these factors. Notably, genetic impairment of these factors strongly reduces the expression of genes with wide nucleosome-deficient regions (e.g., ribosomal protein genes), known to harbor partially-unwrapped nucleosomes. Taken together, Rsc1/2 isoforms are specialized through composition and interactions to manage and remodel partially-unwrapped nucleosomes.



2018 ◽  
Author(s):  
DA Donovan ◽  
JG Crandall ◽  
OGB Banks ◽  
ZD Jensvold ◽  
LE McKnight ◽  
...  

SummaryRegulation of chromatin structure is essential for controlling the access of DNA to factors that require association with specific DNA sequences. The ability to alter chromatin organization in a targeted manner would provide a mechanism for directly manipulating DNA-dependent processes and should provide a means to study direct consequences of chromatin structural changes. Here we describe the development and validation of engineered chromatin remodeling proteins (E-ChRPs) for inducing programmable changes in nucleosome positioning by design. We demonstrate that E-ChRPs function both in vivo and in vitro to specifically reposition target nucleosomes and entire nucleosomal arrays, and possess the ability to evict native DNA-binding proteins through their action. E-ChRPs can be designed with a range of targeting modalities, including the SpyCatcher and dCas9 moieties, resulting in high versatility and enabling diverse future applications. Thus, engineered chromatin remodeling proteins represent a simple and robust means to probe regulation of DNA-dependent processes in different chromatin contexts.



Genetics ◽  
1992 ◽  
Vol 132 (2) ◽  
pp. 375-386 ◽  
Author(s):  
A Vincent ◽  
S W Liebman

Abstract The accurate synthesis of proteins is crucial to the existence of a cell. In yeast, several genes that affect the fidelity of translation have been identified (e.g., omnipotent suppressors, antisuppressors and allosuppressors). We have found that the dominant omnipotent suppressor SUP46 encodes the yeast ribosomal protein S13. S13 is encoded by two similar genes, but only the sup46 copy of the gene is able to fully complement the recessive phenotypes of SUP46 mutations. Both copies of the S13 genes contain introns. Unlike the introns of other duplicated ribosomal protein genes which are highly diverged, the duplicated S13 genes have two nearly identical DNA sequences of 25 and 31 bp in length within their introns. The SUP46 protein has significant homology to the S4 ribosomal protein in prokaryotic-type ribosomes. S4 is encoded by one of the ram (ribosomal ambiguity) genes in Escherichia coli which are the functional equivalent of omnipotent suppressors in yeast. Thus, SUP46 and S4 demonstrate functional as well as sequence conservation between prokaryotic and eukaryotic ribosomal proteins. SUP46 and S4 are most similar in their central amino acid sequences. Interestingly, the alterations resulting from the SUP46 mutations and the segment of the S4 protein involved in binding to the 16S rRNA are within this most conserved region.



2000 ◽  
Vol 20 (23) ◽  
pp. 8879-8888 ◽  
Author(s):  
Zuqin Nie ◽  
Yutong Xue ◽  
Dafeng Yang ◽  
Sharleen Zhou ◽  
Bonnie J. Deroo ◽  
...  

ABSTRACT The SWI/SNF family of chromatin-remodeling complexes facilitates gene activation by assisting transcription machinery to gain access to targets in chromatin. This family includes BAF (also called hSWI/SNF-A) and PBAF (hSWI/SNF-B) from humans and SWI/SNF and Rsc fromSaccharomyces cerevisiae. However, the relationship between the human and yeast complexes is unclear because all human subunits published to date are similar to those of both yeast SWI/SNF and Rsc. Also, the two human complexes have many identical subunits, making it difficult to distinguish their structures or functions. Here we describe the cloning and characterization of BAF250, a subunit present in human BAF but not PBAF. BAF250 contains structural motifs conserved in yeast SWI1 but not in any Rsc components, suggesting that BAF is related to SWI/SNF. BAF250 is also a homolog of the Drosophila melanogaster Osa protein, which has been shown to interact with a SWI/SNF-like complex in flies. BAF250 possesses at least two conserved domains that could be important for its function. First, it has an AT-rich DNA interaction-type DNA-binding domain, which can specifically bind a DNA sequence known to be recognized by a SWI/SNF family-related complex at the β-globin locus. Second, BAF250 stimulates glucocorticoid receptor-dependent transcriptional activation, and the stimulation is sharply reduced when the C-terminal region of BAF250 is deleted. This region of BAF250 is capable of interacting directly with the glucocorticoid receptor in vitro. Our data suggest that BAF250 confers specificity to the human BAF complex and may recruit the complex to its targets through either protein-DNA or protein-protein interactions.



2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Yan Gao ◽  
Songguang Yang ◽  
Lianyu Yuan ◽  
Yuhai Cui ◽  
Keqiang Wu

Chromatin-remodeling complexes affect gene expression by using the energy of ATP hydrolysis to locally disrupt or alter the association of histones with DNA. SWIRM (Swi3p, Rsc8p, and Moira) domain is an alpha-helical domain of about 85 residues in chromosomal proteins. SWIRM domain-containing proteins make up large multisubunit complexes by interacting with other chromatin modification factors and may have an important function in plants. However, little is known about SWIRM domain-containing proteins in plants. In this study, 67 SWIRM domain-containing proteins from 6 plant species were identified and analyzed. Plant SWIRM domain proteins can be divided into three distinct types: Swi-type, LSD1-type, and Ada2-type. Generally, the SWIRM domain forms a helix-turn-helix motif commonly found in DNA-binding proteins. The genes encoding SWIRM domain proteins inOryza sativaare widely expressed, especially in pistils. In addition,OsCHB701andOsHDMA701were downregulated by cold stress, whereasOsHDMA701andOsHDMA702were significantly induced by heat stress. These observations indicate that SWIRM domain proteins may play an essential role in plant development and plant responses to environmental stress.



2015 ◽  
Vol 48 (4) ◽  
pp. 465-470 ◽  
Author(s):  
Yahli Lorch ◽  
Roger D. Kornberg

AbstractThe nucleosome serves as a general gene repressor by the occlusion of regulatory and promoter DNA sequences. Repression is relieved by the SWI/SNF-RSC family of chromatin-remodeling complexes. Research reviewed here has revealed the essential features of the remodeling process.



Cell ◽  
1979 ◽  
Vol 18 (4) ◽  
pp. 1247-1259 ◽  
Author(s):  
John L. Woolford ◽  
Lynna M. Hereford ◽  
Michael Rosbash


1995 ◽  
Vol 73 (11-12) ◽  
pp. 969-977 ◽  
Author(s):  
Francesco Amaldi ◽  
Olga Camacho-Vanegas ◽  
Francesco Cecconi ◽  
Fabrizio Loreni ◽  
Beatrice Cardinali ◽  
...  

In Xenopus laevis, as well as in other vertebrates, ribosomal proteins (r-proteins) are coded by a class of genes that share some organizational and structural features. One of these, also common to genes coding for other proteins involved in the translation apparatus synthesis and function, is the presence within their introns of sequences coding for small nucleolar RNAs. Another feature is the presence of common structures, mainly in the regions surrounding the 5′ ends, involved in their coregulated expression. This is attained at various regulatory levels: transcriptional, posttranscriptional, and translational. Particular attention is given here to regulation at the translational level, which has been studied during Xenopus oogenesis and embryogenesis and also during nutritional changes of Xenopus cultured cells. This regulation, which responds to the cellular need for new ribosomes, operates by changing the fraction of rp-mRNA (ribosomal protein mRNA) engaged on polysomes. A typical 5′ untranslated region characterizing all vertebrate rp-mRNAs analyzed to date is responsible for this translational behaviour: it is always short and starts with an 8–12 nucleotide polypyrimidine tract. This region binds in vitro some proteins that can represent putative trans-acting factors for this translational regulation.Key words: ribosomal proteins, snoRNA, translational regulation, Xenopus laevis.



2017 ◽  
Author(s):  
Alessandro Scacchetti ◽  
Laura Brueckner ◽  
Dhawal Jain ◽  
Tamas Schauer ◽  
Xu Zhang ◽  
...  

ABSTRACTThe chromatin remodeling complexes CHRAC and ACF combine the ATPase ISWI with the signature subunit ACF1. These enzymes catalyze well-studied nucleosome sliding reactions in vitro, but how their actions affect physiological gene expression is unclear. Here we explored the influence of Drosophila CHRAC/ACF on transcription by complementary gain- and loss-of-function approaches.Targeting ACF1 to multiple reporter genes inserted at many different genomic locations revealed a context-dependent inactivation of poorly transcribed reporters in repressive chromatin. Accordingly, single-embryo transcriptome analysis of a Acf knock-out allele showed that only lowly expressed genes are de-repressed in the absence of ACF1. Finally, the nucleosome arrays in Acf-deficient chromatin show loss of physiological regularity, particularly in transcriptionally inactive domains.Taken together our results highlight that ACF1-containing remodeling factors contribute to the establishment of an inactive ground state of the genome through chromatin organization.



2019 ◽  
Author(s):  
Rodrigo O. de Castro ◽  
Victor Goitea ◽  
Luciana Previato ◽  
Agustin Carbajal ◽  
Courtney T. Griffin ◽  
...  

AbstractTestis development and sustained germ cell production in adults rely on the establishment of spermatogonia stem cells and their proper differentiation into mature gametes. Control of these processes involves not only promoting the expression of genes required for cell survival and differentiation but also repressing other cell fates. This level of transcriptional control requires chromatin-remodeling complexes that restrict or promote transcription machinery. Here, we investigated the roles of the NUcleosome Remodeling and Deacetylase (NURD) complex during spermatogenesis. Our cellular and biochemical analyses revealed differential expression and composition of NURD subunits in gametocytes at different stages of testis development. Germ cell-specific deletion of the NURD catalytic component CHD4, but not CHD3, resulted in arrested early gamete development due to failed cell survival of the undifferentiated spermatogonia stem cell population. Genome-wide CHD4 chromatin localization and transcriptomic analyses revealed that CHD4 binds the promoters and regulates the expression of genes involved in spermatogonia cell survival and differentiation. These results uncover the requirements of CHD4 in mammalian gonad development, and point to unique roles for the NURD complex with respect to other chromatin remodelers during gamete development.Significance StatementGametogenesis is a fundamental developmental program required for sustained fertility and survival of all sexually reproducing species. The developing male gamete undergoes numerous cell divisions and developmental stage transitions that are carefully monitored by epigenetic mechanisms. One prominent mechanism is directed by chromatin remodeling complexes, which modify chromatin structure and thereby control fundamental cellular processes such as gene transcription. In this work, we focused in understanding the role of CHD4 and CHD3 proteins, catalytic subunits of the NURD chromatin-remodeling complex, in mouse gametogenesis. We find that CHD4 has an essential function in gametogenesis, with an absolute requirement for survival of spermatogonia populations in the developing testis. This is accompanied by CHD4-mediated transcriptional regulation of genes important for spermatogonia survival, and differentiation.



Sign in / Sign up

Export Citation Format

Share Document