scholarly journals Chromatin‐remodeling complexes: conserved and plant‐specific subunits in Arabidopsis

2021 ◽  
Author(s):  
Ji‐Yun Shang ◽  
Xin‐Jian He
Keyword(s):  
Chromatin Remodeling ◽  
Chromatin Remodeling Complexes

Abstract 17084: Nuclear Smooth Muscle α-actin Participates in Chromatin Remodeling at Smooth Muscle Contractile Gene Promoters

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Callie Kwartler ◽  
Shuangtao Ma ◽  
Caroline Kernell ◽  
Xue-yan Duan ◽  
Charis Wang ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Cardiac Muscle ◽  
Chromatin Remodeling ◽  
Muscle Cells ◽  
Cytoskeletal Proteins ◽  
Nuclear Localization Sequence ◽  
Serum Starvation ◽  
Cell Fractionation ◽  
Gene Promoters ◽  
Chromatin Remodeling Complexes

Actin genes encode for cytoskeletal proteins that polymerize to function in cellular motility, adhesion, and contraction. In mammalian cells, ubiquitously expressed β-actin also moves into the nucleus and associates with chromatin remodeling complexes, however a nuclear function of muscle-specific α-actins has not been previously assessed. We hypothesized that smooth muscle α-actin (SMA) plays a role in chromatin remodeling during the differentiation of smooth muscle cells (SMCs) to enable cell fate specification of SMCs. In explanted SMCs from human and mouse ascending aortas, cell fractionation and 2D gel electrophoresis identify both SMA and β-actin in the nuclear lysates. Nuclear SMA but not β-actin accumulates with SMC differentiation driven by serum starvation and transforming growth factor-β1 treatment. SMA accumulates into the nucleus early in the differentiation of SMCs from neural crest progenitor cells, prior to cytosolic accumulation. Immunoprecipitation studies show that SMA binds specifically to the INO80 and the SWI/SNF chromatin remodeling complexes, and this binding increases with SMC differentiation. Chromatin immunoprecipitation reveals that SMA is bound to the promoters of SMC-specific genes, including Acta2 , Cnn1, and Myh11 and that SMA is enriched over β-actin at these promoters with SMC differentiation. Finally, overexpression of SMA tagged with a nuclear localization sequence (NLS) in multiple cell types increases expression of SMC markers, whereas NLS-tagged β-actin localizes to the nucleus to the same extent but does not increase SMC marker expression in any cell type. Finally, we assessed whether skeletal muscle α-actin (SKA) and cardiac muscle α-actin (CMA) may play a similar role in skeletal and cardiac muscle cells. Both SKA and CMA translocate into the nucleus. CMA accumulates into the nucleus early in the differentiation of cardiomyocytes from pluripotent stem cells. Immunoprecipitation reveals that SKA binds to the SWI/SNF complex in differentiated C2C12 myotube cell cultures. These data support that nuclear SMA enriches with and participates in SMC differentiation, and suggest a potential nuclear role for other muscle specific α-actins in developing muscle cells.

scholarly journals Combinatorial depletion analysis to assemble the network architecture of the SAGA and ADA chromatin remodeling complexes

2011 ◽  
Vol 7 (1) ◽  
pp. 503 ◽  
Author(s):  
Kenneth K Lee ◽  
Mihaela E Sardiu ◽  
Selene K Swanson ◽  
Joshua M Gilmore ◽  
Michael Torok ◽  
...  
Keyword(s):  
Chromatin Remodeling ◽  
Network Architecture ◽  
Chromatin Remodeling Complexes

scholarly journals Identification and Functional Characterization of Protest SWI/SNF and ISWI Complexes

2021 ◽  
Author(s):  
Alejandro Saettone Chipana
Keyword(s):  
Chromatin Remodeling ◽  
Tetrahymena Thermophila ◽  
Affinity Purification ◽  
Functional Characterization ◽  
Peptide Array ◽  
Interacting Proteins ◽  
Silent Chromatin ◽  
Lysine Residues ◽  
Chromatin Remodeling Complexes

The thesis aims to identify and initiate functional characterization of the SWI/SNF and ISWI complexes in Tetrahymena thermophila. Through affinity purification of the conserved subunit Snf5 followed by mass spectrometry (AP-MS), I identified the first SWI/SNF complex in protists. One of the subunits I found is a small bromodomain containing protein named Ibd1. Through AP-MS of Ibd1 I found Ibd1 is versatile and interacts with several additional chromatin remodeling complexes. Bromodomains are known to have affinity for acetylated lysine residues within proteins such as histones. A peptide array experiment suggests that Ibd1 also has affinity for acetylated chromatin. Indirect immunofluorescence (IF) of Ibd1 hints at a role in transcription. My analysis of Tetrahymena Iswi1 shows expression during meiosis, vegetative growth and starvation. IF data shows its localization is consistent with Iswi1 function in mitosis/meiosis or maintenance of silent chromatin. AP-MS of ISW1 discovered several interacting proteins of unknown function.

Human CCAAT/Enhancer-Binding Protein β Interacts with Chromatin Remodeling Complexes of the Imitation Switch Subfamily

Biochemistry ◽  
2012 ◽  
Vol 51 (5) ◽  
pp. 952-962 ◽  
Author(s):  
Ximena P. Steinberg ◽  
Matias I. Hepp ◽  
Yaiza Fernández García ◽  
Tamaki Suganuma ◽  
Selene K. Swanson ◽  
...  
Keyword(s):  
Chromatin Remodeling ◽  
Binding Protein ◽  
Enhancer Binding Protein ◽  
Ccaat Enhancer Binding Protein ◽  
Chromatin Remodeling Complexes

scholarly journals A Specificity and Targeting Subunit of a Human SWI/SNF Family-Related Chromatin-Remodeling Complex

2000 ◽  
Vol 20 (23) ◽  
pp. 8879-8888 ◽  
Author(s):  
Zuqin Nie ◽  
Yutong Xue ◽  
Dafeng Yang ◽  
Sharleen Zhou ◽  
Bonnie J. Deroo ◽  
...  
Keyword(s):  
Glucocorticoid Receptor ◽  
Chromatin Remodeling ◽  
Protein Interactions ◽  
Transcriptional Activation ◽  
Gene Activation ◽  
Dna Interaction ◽  
Protein Protein Interactions ◽  
Baf Complex ◽  
Chromatin Remodeling Complexes

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.

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