scholarly journals Osa-containing Brahma chromatin remodeling complexes are required for the repression of Wingless target genes

2000 ◽  
Vol 14 (24) ◽  
pp. 3140-3152 ◽  
Author(s):  
R. T. Collins
2001 ◽  
Vol 21 (19) ◽  
pp. 6450-6460 ◽  
Author(s):  
Thomas G. Fazzio ◽  
Charles Kooperberg ◽  
Jesse P. Goldmark ◽  
Cassandra Neal ◽  
Ryan Basom ◽  
...  

ABSTRACT The yeast Isw2 chromatin remodeling complex functions in parallel with the Sin3-Rpd3 histone deacetylase complex to repress early meiotic genes upon recruitment by Ume6p. For many of these genes, the effect of an isw2 mutation is partially masked by a functional Sin3-Rpd3 complex. To identify the full range of genes repressed or activated by these factors and uncover hidden targets of Isw2-dependent regulation, we performed full genome expression analyses using cDNA microarrays. We find that the Isw2 complex functions mainly in repression of transcription in a parallel pathway with the Sin3-Rpd3 complex. In addition to Ume6 target genes, we find that many Ume6-independent genes are derepressed in mutants lacking functional Isw2 and Sin3-Rpd3 complexes. Conversely, we find thatume6 mutants, but not isw2 sin3 or isw2 rpd3 double mutants, have reduced fidelity of mitotic chromosome segregation, suggesting that one or more functions of Ume6p are independent of Sin3-Rpd3 and Isw2 complexes. Chromatin structure analyses of two nonmeiotic genes reveals increased DNase I sensitivity within their regulatory regions in an isw2 mutant, as seen previously for one meiotic locus. These data suggest that the Isw2 complex functions at Ume6-dependent and -independent loci to create DNase I-inaccessible chromatin structure by regulating the positioning or placement of nucleosomes.


Cells ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 502 ◽  
Author(s):  
Ryan E. Hillmer ◽  
Brian A. Link

Hippo signaling controls cellular processes that ultimately impact organogenesis and homeostasis. Consequently, disease states including cancer can emerge when signaling is deregulated. The major pathway transducers Yap and Taz require cofactors to impart transcriptional control over target genes. Research into Yap/Taz-mediated epigenetic modifications has revealed their association with chromatin-remodeling complex proteins as a means of altering chromatin structure, therefore affecting accessibility and activity of target genes. Specifically, Yap/Taz have been found to associate with factors of the GAGA, Ncoa6, Mediator, Switch/sucrose nonfermentable (SWI/SNF), and Nucleosome Remodeling and Deacetylase (NuRD) chromatin-remodeling complexes to alter the accessibility of target genes. This review highlights the different mechanisms by which Yap/Taz collaborate with other factors to modify DNA packing at specific loci to either activate or repress target gene transcription.


Author(s):  
Gali Umschweif ◽  
Lucian Medrihan ◽  
Kathryn A. McCabe ◽  
Yotam Sagi ◽  
Paul Greengard

AbstractThe delayed behavioral response to chronic antidepressants depends on dynamic changes in the hippocampus. It was suggested that the antidepressant protein p11 and the chromatin remodeling factor SMARCA3 mediate this delayed response by inducing transcriptional changes in hippocampal neurons. However, what target genes are regulated by the p11/SMARCA3 complex to mediate the behavioral response to antidepressants, and what cell type mediates these molecular changes remain unknown. Here we report that the p11/SMARCA3 complex represses Neurensin-2 transcription in hippocampal parvalbumin-expressing interneurons after chronic treatment with Selective Serotonin Reuptake Inhibitors (SSRI). The behavioral response to antidepressants requires upregulation of p11, accumulation of SMARCA3 in the cell nucleus, and a consequent repression of Neurensin-2 transcription in these interneurons. We elucidate a functional role for p11/SMARCA3/Neurensin-2 pathway in regulating AMPA-receptor signaling in parvalbumin-expressing interneurons, a function that is enhanced by chronic treatment with SSRIs. These results link SSRIs to dynamic glutamatergic changes and implicate p11/SMARCA3/Neurensin-2 pathway in the development of more specific and efficient therapeutic strategies for neuropsychiatric disorders.


Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Callie Kwartler ◽  
Shuangtao Ma ◽  
Caroline Kernell ◽  
Xue-yan Duan ◽  
Charis Wang ◽  
...  

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.


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