scholarly journals Sentinels of chromatin: chromodomain helicase DNA-binding proteins in development and disease

2021 ◽  
Vol 35 (21-22) ◽  
pp. 1403-1430
Author(s):  
Andrej Alendar ◽  
Anton Berns
Keyword(s):  
Dna Binding ◽  
Global Changes ◽  
Aberrant Expression ◽  
Genetic Studies ◽  
Chromatin Remodelers ◽  
Chromatin Dynamics ◽  
Dna Accessibility ◽  
Dna Modifications ◽  
Nucleosomal Structure ◽  
Dna Copy Number Alterations

Chromatin is highly dynamic, undergoing continuous global changes in its structure and type of histone and DNA modifications governed by processes such as transcription, repair, replication, and recombination. Members of the chromodomain helicase DNA-binding (CHD) family of enzymes are ATP-dependent chromatin remodelers that are intimately involved in the regulation of chromatin dynamics, altering nucleosomal structure and DNA accessibility. Genetic studies in yeast, fruit flies, zebrafish, and mice underscore essential roles of CHD enzymes in regulating cellular fate and identity, as well as proper embryonic development. With the advent of next-generation sequencing, evidence is emerging that these enzymes are subjected to frequent DNA copy number alterations or mutations and show aberrant expression in malignancies and other human diseases. As such, they might prove to be valuable biomarkers or targets for therapeutic intervention.

scholarly journals Alcohol use disorder causes global changes in splicing in the human brain

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Derek Van Booven ◽  
Mengying Li ◽  
J. Sunil Rao ◽  
Ilya O. Blokhin ◽  
R. Dayne Mayfield ◽  
...  
Keyword(s):  
Alcohol Use ◽  
Human Brain ◽  
Alcohol Use Disorder ◽  
Brain Regions ◽  
Gene Set Enrichment Analysis ◽  
Splicing Factor ◽  
Central Nucleus ◽  
Global Changes ◽  
Aberrant Expression ◽  
Altered Expression

AbstractAlcohol use disorder (AUD) is a widespread disease leading to the deterioration of cognitive and other functions. Mechanisms by which alcohol affects the brain are not fully elucidated. Splicing constitutes a nuclear process of RNA maturation, which results in the formation of the transcriptome. We tested the hypothesis as to whether AUD impairs splicing in the superior frontal cortex (SFC), nucleus accumbens (NA), basolateral amygdala (BLA), and central nucleus of the amygdala (CNA). To evaluate splicing, bam files from STAR alignments were indexed with samtools for use by rMATS software. Computational analysis of affected pathways was performed using Gene Ontology Consortium, Gene Set Enrichment Analysis, and LncRNA Ontology databases. Surprisingly, AUD was associated with limited changes in the transcriptome: expression of 23 genes was altered in SFC, 14 in NA, 102 in BLA, and 57 in CNA. However, strikingly, mis-splicing in AUD was profound: 1421 mis-splicing events were detected in SFC, 394 in NA, 1317 in BLA, and 469 in CNA. To determine the mechanism of mis-splicing, we analyzed the elements of the spliceosome: small nuclear RNAs (snRNAs) and splicing factors. While snRNAs were not affected by alcohol, expression of splicing factor heat shock protein family A (Hsp70) member 6 (HSPA6) was drastically increased in SFC, BLA, and CNA. Also, AUD was accompanied by aberrant expression of long noncoding RNAs (lncRNAs) related to splicing. In summary, alcohol is associated with genome-wide changes in splicing in multiple human brain regions, likely due to dysregulation of splicing factor(s) and/or altered expression of splicing-related lncRNAs.

scholarly journals GBAF, a small BAF sub-complex with big implications: a systematic review

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Sarah M. Innis ◽  
Birgit Cabot
Keyword(s):  
Chromatin Remodeling ◽  
Cellular Differentiation ◽  
Complex Function ◽  
Therapeutic Interventions ◽  
Mammalian Development ◽  
Aberrant Expression ◽  
Chromatin Remodelers ◽  
Baf Complex ◽  
Chromatin Remodeling Complexes ◽  
Histone Modifying Enzymes

Abstract ATP-dependent chromatin remodeling by histone-modifying enzymes and chromatin remodeling complexes is crucial for maintaining chromatin organization and facilitating gene transcription. In the SWI/SNF family of ATP-dependent chromatin remodelers, distinct complexes such as BAF, PBAF, GBAF, esBAF and npBAF/nBAF are of particular interest regarding their implications in cellular differentiation and development, as well as in various diseases. The recently identified BAF subcomplex GBAF is no exception to this, and information is emerging linking this complex and its components to crucial events in mammalian development. Furthermore, given the essential nature of many of its subunits in maintaining effective chromatin remodeling function, it comes as no surprise that aberrant expression of GBAF complex components is associated with disease development, including neurodevelopmental disorders and numerous malignancies. It becomes clear that building upon our knowledge of GBAF and BAF complex function will be essential for advancements in both mammalian reproductive applications and the development of more effective therapeutic interventions and strategies. Here, we review the roles of the SWI/SNF chromatin remodeling subcomplex GBAF and its subunits in mammalian development and disease.

scholarly journals Four of the seven zinc fingers of the Evi-1 myeloid-transforming gene are required for sequence-specific binding to GA(C/T)AAGA(T/C)AAGATAA.

1993 ◽  
Vol 13 (7) ◽  
pp. 4291-4300 ◽  
Author(s):  
R Delwel ◽  
T Funabiki ◽  
B L Kreider ◽  
K Morishita ◽  
J N Ihle
Keyword(s):  
Dna Binding ◽  
Specific Binding ◽  
Zinc Fingers ◽  
Consensus Sequence ◽  
Myelogenous Leukemia ◽  
Chromosome Band ◽  
Aberrant Expression ◽  
Relative Specificity ◽  
Acute Myelogenous ◽  
Binding Sequence

Expression of the Evi-1 gene is activated in murine myeloid leukemias by retroviral insertions and in human acute myelogenous leukemia by translocations and inversions involving chromosome band 3q26 where the gene resides. Aberrant expression of the Evi-1 gene has been shown to interfere with myeloid differentiation, which is proposed to be the basis for its role in leukemias. The Evi-1 gene encodes a 145-kDa DNA-binding protein containing two domains of seven and three Cys2-His2 zinc fingers. Previous studies identified a portion of the consensus DNA-binding sequence for the first domain of zinc fingers. The experiments presented here extend these studies and demonstrate that the first domain recognizes a consensus of 15 nucleotides consisting of GA(C/T)AAGA(T/C)AAGATAA. The first three fingers of the first domain do not detectably bind DNA but contribute to the binding by conferring a relative specificity for GACAA verses GATAA in the first position. The first three fingers also contribute to optimal binding of the 15-nucleotide consensus sequence.

Post-translational modifications and chromatin dynamics

2019 ◽  
Vol 63 (1) ◽  
pp. 89-96 ◽  
Author(s):  
Thomas O. Tolsma ◽  
Jeffrey C. Hansen
Keyword(s):  
Dynamic Structure ◽  
Higher Order ◽  
Post Translational Modifications ◽  
Chromatin Dynamics ◽  
Dna Accessibility ◽  
In Vivo Analysis ◽  
Nuclear Environment ◽  
Biological State

Abstract The dynamic structure of chromatin is linked to gene regulation and many other biological functions. Consequently, it is of importance to understand the factors that regulate chromatin dynamics. While the in vivo analysis of chromatin has verified that histone post-translational modifications play a role in modulating DNA accessibility, the complex nuclear environment and multiplicity of modifications prevents clear conclusions as to how individual modifications influence chromatin dynamics in the cell. For this reason, in vitro analyses of model reconstituted nucleosomal arrays has been pivotal in understanding the dynamic nature of chromatin compaction and the affects that specific post-translational modifications can have on the higher order chromatin structure. In this mini-review, we briefly describe the dynamic chromatin structures that have been observed in vitro and the environmental conditions that give rise to these various conformational states. Our focus then turns to a discussion of the specific histone post-translational modifications that have been shown to alter formation of these higher order chromatin structures in vitro and how this may relate to the biological state and accessibility of chromatin in vivo.

Alveolus formation: what have we learned from genetic studies?

2004 ◽  
Vol 97 (4) ◽  
pp. 1543-1548 ◽  
Author(s):  
Cong Yan ◽  
Hong Du
Keyword(s):  
Molecular Mechanisms ◽  
Environmental Changes ◽  
Cell Types ◽  
Model Systems ◽  
Normal Lung ◽  
Aberrant Expression ◽  
Genetic Studies ◽  
Basic Functions ◽  
Pathogen Clearance ◽  
Alveolar Formation

The respiratory system has two basic functions: air exchange and pathogen clearance. The conducting airway and alveolar parenchyma are the basic structures to fulfill these functions during respiratory cycles. In humans, there are ∼40 cell types in the lung that coordinately work together through various structural and signaling molecules. These molecules are vital for maintaining normal lung functions in response to environmental changes. Aberrant expression of these molecules can jeopardize human health and cause various pulmonary diseases. In this article, we will review some recent progress made in the pulmonary field, using genetic animal model systems to elucidate molecular mechanisms that are important for alveolar formation and lung diseases.

scholarly journals Global changes in nitration levels and DNA binding profile of Trypanosoma cruzi histones induced by incubation with host extracellular matrix

2020 ◽  
Vol 14 (5) ◽  
pp. e0008262 ◽  
Author(s):  
Rubens Daniel Miserani Magalhães ◽  
Eliciane Cevolani Mattos ◽  
Andrei Rozanski ◽  
Pedro Alexandre Favoretto Galante ◽  
Giuseppe Palmisano ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Dna Binding ◽  
Trypanosoma Cruzi ◽  
Global Changes ◽  
Binding Profile

scholarly journals E2a-Pbx1 induces aberrant expression of tissue-specific and developmentally regulated genes when expressed in NIH 3T3 fibroblasts.

1997 ◽  
Vol 17 (3) ◽  
pp. 1503-1512 ◽  
Author(s):  
X Fu ◽  
M P Kamps
Keyword(s):  
Dna Binding ◽  
Target Genes ◽  
Ectopic Expression ◽  
Cellular Transformation ◽  
Transactivation Domain ◽  
Developmentally Regulated ◽  
Aberrant Expression ◽  
Tissue Specific ◽  
3T3 Fibroblasts ◽  
Nih 3T3

The E2a-Pbx1 oncoprotein contains the transactivation domain of E2a joined to the DNA-binding homeodomain (HD) of Pbx1. In mice, E2a-Pbx1 transforms T lymphoblasts and fibroblasts and blocks myeloblast differentiation. Pbx1 and E2a-Pbx1 bind DNA as heterodimers with other HD proteins whose expression is tissue specific. While the transactivation domain of E2a is required for all forms of transformation, DNA binding by the Pbx1 HD is essential for blocking myeloblast differentiation but dispensable for fibroblast or T-lymphoblast transformation. These properties suggest (i) that E2a-Pbx1 causes cellular transformation by activating gene transcription, (ii) that transcription of E2a-Pbx1 target genes is normally regulated by ubiquitous Pbx proteins and tissue-specific partners, and (iii) that DNA-binding mutants of E2a-Pbx1 activate a subset of all gene targets. To test these predictions, genes induced in NIH 3T3 fibroblasts by E2a-Pbx1 were identified and examined for tissue- and stage-specific expression and their differential abilities to be upregulated by E2a-Pbx1 in NIH 3T3 fibroblasts and myeloblasts and by a DNA-binding mutant of E2a-Pbx1 in NIH 3T3 cells. Of 12 RNAs induced by E2a-Pbx1, 4 encoded known proteins (a J-C region of the immunoglobulin kappa light chain, natriuretic peptide receptor C, mitochondrial fumarase, and the 3',5'-cyclic nucleotide phosphodiesterase, PDE1A) and 5 encoded new proteins related to angiogenin, ion channels, villin, epidermal growth factor repeat proteins, and the human 2.19 gene product. Expression of many of these genes was tissue specific or developmentally regulated, and most were not expressed in fibroblasts, indicating that E2a-Pbx1 can induce ectopic expression of genes associated with lineage-specific differentiation.

scholarly journals p53-Mediated Repression of Alpha-Fetoprotein Gene Expression by Specific DNA Binding

1999 ◽  
Vol 19 (2) ◽  
pp. 1279-1288 ◽  
Author(s):  
Kathleen C. Lee ◽  
Alison J. Crowe ◽  
Michelle Craig Barton
Keyword(s):  
Gene Expression ◽  
Dna Binding ◽  
Western Blot ◽  
P53 Protein ◽  
Transient Transfection ◽  
Alpha Fetoprotein ◽  
Single Mutation ◽  
Hepatic Differentiation ◽  
Aberrant Expression ◽  
Tissue Specific

ABSTRACT Aberrant expression of the alpha-fetoprotein (AFP) gene is characteristic of a majority of hepatocellular carcinoma cases and serves as a diagnostic tumor-specific marker. By dissecting regulatory mechanisms through electromobility gel shift, transient-transfection, Western blot, and in vitro transcription analyses, we find that AFP gene expression is controlled in part by mutually exclusive binding of two trans-acting factors, p53 and hepatic nuclear factor 3 (HNF-3). HNF-3 protein activates while p53 represses AFP transcription through sequence-specific binding within the previously identified AFP developmental repressor domain. A single mutation within the DNA binding domain of p53 protein or a mutation of the p53 DNA binding element within the AFP developmental repressor eliminates p53-repressive effects in both transient-transfection and cell-free expression systems. Coexpression of p300 histone acetyltransferase, which has been shown to acetylate p53 and increase specific DNA binding, amplifies the p53-mediated repression. Western blot analysis of proteins present in developmentally staged, liver nuclear extracts reveal a one-to-one correlation between activation of p53 protein and repression of AFP during hepatic development. Induction of p53 in response to actinomycin D or hypoxic stress decreases AFP expression. Studies in fibroblast cells lacking HNF-3 further support a model for p53-mediated repression that is both passive through displacement of a tissue-specific activating factor and active in the presence of tissue-specific corepressors. This mechanism for p53-mediated repression of AFP gene expression may be active during hepatic differentiation and lost in the process of tumorigenesis.

scholarly journals Tracking chromatin state changes using μMap photo-proximity labeling

2021 ◽  
Author(s):  
Ciaran P Seath ◽  
Antony J Burton ◽  
David W. C. MacMillan ◽  
Tom W Muir
Keyword(s):  
Cell Fate ◽  
Small Molecule ◽  
Protein Interactions ◽  
Control Cell ◽  
Global Changes ◽  
Therapeutic Effects ◽  
Protein Protein Interactions ◽  
Chromatin Remodelers ◽  
Expression Levels ◽  
Epigenetic Drug

Interactions between biomolecules, particularly proteins, underlie all cellular processes, and ultimately control cell fate. Perturbation of native interactions through mutation, changes in expression levels, or external stimuli leads to altered cellular physiology and can result in either disease or therapeutic effects. Mapping these interactions and determining how they respond to stimulus is the genesis of many drug development efforts, leading to new therapeutic targets and improvements in human health. However, in the complex environment of the nucleus it is challenging to determine protein-protein interactions due to low abundance, transient or multi-valent binding, and a lack of technologies that are able to interrogate these interactions without disrupting the protein binding surface under study. Chromatin remodelers, modifying enzymes, interactors, and transcription factors can all be redirected by subtle changes to the microenvironment, causing global changes in protein expression levels and subsequent physiology. Here, we describe the Chroma-μMap method for the traceless incorporation of Ir-photosensitizers into the nuclear microenvironment using engineered split inteins. These Ir-catalysts can activate diazirine warheads to form reactive carbenes within a ~10 nm radius, cross-linking with proteins within the immediate microenvironment for analysis via quantitative chemoproteomics. We demonstrate this concept on nine different nuclear proteins with varied function and in each case, elucidating their microenvironments. Additionally, we show that this short-range proximity labelling method can reveal the critical changes in interactomes in the presence of cancer-associated mutations, as well as treatment with small-molecule inhibitors. Chroma-μMap improves our fundamental understanding of nuclear protein-protein interactions, as well as the effects that small molecule therapeutics have on the local chromatin environment, and in doing so is expected to have a significant impact on the field of epigenetic drug discovery in both academia and industry.

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