scholarly journals pH controlled histone acetylation amplifies melanocyte differentiation program downstream of MITF

2019 ◽  
Author(s):  
Desingu Ayyappa Raja ◽  
Vishvabandhu Gotherwal ◽  
Yogaspoorthi J Subramaniam ◽  
Farina Sultan ◽  
Archana Vats ◽  
...  

AbstractTanning response and melanocyte differentiation are mediated by the central transcription factor MITF. Enigmatically, these involve rapid and selective induction of melanocyte maturation genes, while concomitantly maintaining the expression of other effectors. In this study using cell-based and zebrafish model systems, we elucidate a pH mediated feed-forward mechanism of epigenetic regulation that enables selective amplification of melanocyte maturation program. We demonstrate that MITF activation directly elevates the expression of Carbonic Anhydrase 14 (Ca14) enzyme. Nuclear localized Ca14 increases the intracellular pH, resulting in the activation of histone acetyl transferase activity of p300/CBP. In turn enhanced H3K27 histone acetylation marks of select differentiation genes facilitates their amplified expression by MITF. CRISPR-mediated targeted missense mutation of CA14 in zebrafish results in immature acidic melanocytes with decreased pigmentation, establishing the centrality of this mechanism in rapidly activating melanocyte differentiation. Thereby we reveal a novel epigenetic control through pH modulation that reinforces a deterministic cell fate by altering chromatin dynamics.

2020 ◽  
Vol 21 (18) ◽  
pp. 6912
Author(s):  
Magdalena Jarosz ◽  
Mieke Van Lijsebettens ◽  
Magdalena Woloszynska

Contrary to the conserved Elongator composition in yeast, animals, and plants, molecular functions and catalytic activities of the complex remain controversial. Elongator was identified as a component of elongating RNA polymerase II holoenzyme in yeast, animals, and plants. Furthermore, it was suggested that Elonagtor facilitates elongation of transcription via histone acetyl transferase activity. Accordingly, phenotypes of Arabidopsis elo mutants, which show development, growth, or immune response defects, correlate with transcriptional downregulation and the decreased histone acetylation in the coding regions of crucial genes. Plant Elongator was also implicated in other processes: transcription and processing of miRNA, regulation of DNA replication by histone acetylation, and acetylation of alpha-tubulin. Moreover, tRNA modification, discovered first in yeast and confirmed in plants, was claimed as the main activity of Elongator, leading to specificity in translation that might also result indirectly in a deficiency in transcription. Heterologous overexpression of individual Arabidopsis Elongator subunits and their respective phenotypes suggest that single Elongator subunits might also have another function next to being a part of the complex. In this review, we shall present the experimental evidence of all molecular mechanisms and catalytic activities performed by Elongator in nucleus and cytoplasm of plant cells, which might explain how Elongator regulates growth, development, and immune responses.


2006 ◽  
Vol 290 (5) ◽  
pp. G1016-G1024 ◽  
Author(s):  
Tjalling Bosse ◽  
Herbert M. van Wering ◽  
Marieke Gielen ◽  
Lauren N. Dowling ◽  
John J. Fialkovich ◽  
...  

Hepatocyte nuclear factor-1α (HNF-1α) is a modified homeodomain-containing transcription factor that has been implicated in the regulation of intestinal genes. To define the importance and underlying mechanism of HNF-1α for the regulation of intestinal gene expression in vivo, we analyzed the expression of the intestinal differentiation markers and putative HNF-1α targets lactase-phlorizin hydrolase (LPH) and sucrase-isomaltase (SI) in hnf1α null mice. We found that in adult jejunum, LPH mRNA in hnf1α−/− mice was reduced 95% compared with wild-type controls ( P < 0.01, n = 4), whereas SI mRNA was virtually identical to that in wild-type mice. Furthermore, SI mRNA abundance was unchanged in the absence of HNF-1α along the length of the adult mouse small intestine as well as in newborn jejunum. We found that HNF-1α occupies the promoters of both the LPH and SI genes in vivo. However, in contrast to liver and pancreas, where HNF-1α regulates target genes by recruitment of histone acetyl transferase activity to the promoter, the histone acetylation state of the LPH and SI promoters was not affected by the presence or absence of HNF-1α. Finally, we showed that a subset of hypothesized intestinal target genes is regulated by HNF-1α in vivo and that this regulation occurs in a defined tissue-specific and developmental context. These data indicate that HNF-1α is an activator of a subset of intestinal genes and induces these genes through an alternative mechanism in which it is dispensable for chromatin remodeling.


PLoS Genetics ◽  
2021 ◽  
Vol 17 (8) ◽  
pp. e1009730
Author(s):  
Gwenaëlle Gavory ◽  
Caroline Baril ◽  
Gino Laberge ◽  
Gawa Bidla ◽  
Surapong Koonpaew ◽  
...  

Acute myeloid leukemia (AML) underlies the uncontrolled accumulation of immature myeloid blasts. Several cytogenetic abnormalities have been associated with AML. Among these is the NUP98-HOXA9 (NA9) translocation that fuses the Phe-Gly repeats of nucleoporin NUP98 to the homeodomain of the transcription factor HOXA9. The mechanisms enabling NA9-induced leukemia are poorly understood. Here, we conducted a genetic screen in Drosophila for modifiers of NA9. The screen uncovered 29 complementation groups, including genes with mammalian homologs known to impinge on NA9 activity. Markedly, the modifiers encompassed a diversity of functional categories, suggesting that NA9 perturbs multiple intracellular events. Unexpectedly, we discovered that NA9 promotes cell fate transdetermination and that this phenomenon is greatly influenced by NA9 modifiers involved in epigenetic regulation. Together, our work reveals a network of genes functionally connected to NA9 that not only provides insights into its mechanism of action, but also represents potential therapeutic targets.


Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 212
Author(s):  
Katharina Amschler ◽  
Michael P. Schön

Cancer comprises a large group of complex diseases which arise from the misrouted interplay of mutated cells with other cells and the extracellular matrix. The extracellular matrix is a highly dynamic structure providing biochemical and biophysical cues that regulate tumor cell behavior. While the relevance of biochemical signals has been appreciated, the complex input of biophysical properties like the variation of ligand density and distribution is a relatively new field in cancer research. Nanotechnology has become a very promising tool to mimic the physiological dimension of biophysical signals and their positive (i.e., growth-promoting) and negative (i.e., anti-tumoral or cytotoxic) effects on cellular functions. Here, we review tumor-associated cellular functions such as proliferation, epithelial-mesenchymal transition (EMT), invasion, and phenotype switch that are regulated by biophysical parameters such as ligand density or substrate elasticity. We also address the question of how such factors exert inhibitory or even toxic effects upon tumor cells. We describe three principles of nanostructured model systems based on block copolymer nanolithography, electron beam lithography, and DNA origami that have contributed to our understanding of how biophysical signals direct cancer cell fate.


Genetics ◽  
2003 ◽  
Vol 165 (3) ◽  
pp. 1623-1628
Author(s):  
Hediye Nese Cinar ◽  
Keri L Richards ◽  
Kavita S Oommen ◽  
Anna P Newman

Abstract We isolated egl-13 mutants in which the cells of the Caenorhabditis elegans uterus initially appeared to develop normally but then underwent an extra round of cell division. The data suggest that egl-13 is required for maintenance of the cell fate.


2021 ◽  
Vol 22 (13) ◽  
pp. 6713
Author(s):  
Romana Bohuslavova ◽  
Ondrej Smolik ◽  
Jessica Malfatti ◽  
Zuzana Berkova ◽  
Zaneta Novakova ◽  
...  

Diabetes is a metabolic disease that involves the death or dysfunction of the insulin-secreting β cells in the pancreas. Consequently, most diabetes research is aimed at understanding the molecular and cellular bases of pancreatic development, islet formation, β-cell survival, and insulin secretion. Complex interactions of signaling pathways and transcription factor networks regulate the specification, growth, and differentiation of cell types in the developing pancreas. Many of the same regulators continue to modulate gene expression and cell fate of the adult pancreas. The transcription factor NEUROD1 is essential for the maturation of β cells and the expansion of the pancreatic islet cell mass. Mutations of the Neurod1 gene cause diabetes in humans and mice. However, the different aspects of the requirement of NEUROD1 for pancreas development are not fully understood. In this study, we investigated the role of NEUROD1 during the primary and secondary transitions of mouse pancreas development. We determined that the elimination of Neurod1 impairs the expression of key transcription factors for α- and β-cell differentiation, β-cell proliferation, insulin production, and islets of Langerhans formation. These findings demonstrate that the Neurod1 deletion altered the properties of α and β endocrine cells, resulting in severe neonatal diabetes, and thus, NEUROD1 is required for proper activation of the transcriptional network and differentiation of functional α and β cells.


2021 ◽  
Vol 12 (3) ◽  
Author(s):  
Vishwanie S. Budhram-Mahadeo ◽  
Matthew R. Solomons ◽  
Eeshan A. O. Mahadeo-Heads

AbstractMetabolic and cardiovascular diseases are highly prevalent and chronic conditions that are closely linked by complex molecular and pathological changes. Such adverse effects often arise from changes in the expression of genes that control essential cellular functions, but the factors that drive such effects are not fully understood. Since tissue-specific transcription factors control the expression of multiple genes, which affect cell fate under different conditions, then identifying such regulators can provide valuable insight into the molecular basis of such diseases. This review explores emerging evidence that supports novel and important roles for the POU4F2/Brn-3b transcription factor (TF) in controlling cellular genes that regulate cardiometabolic function. Brn-3b is expressed in insulin-responsive metabolic tissues (e.g. skeletal muscle and adipose tissue) and is important for normal function because constitutive Brn-3b-knockout (KO) mice develop profound metabolic dysfunction (hyperglycaemia; insulin resistance). Brn-3b is highly expressed in the developing hearts, with lower levels in adult hearts. However, Brn-3b is re-expressed in adult cardiomyocytes following haemodynamic stress or injury and is necessary for adaptive cardiac responses, particularly in male hearts, because male Brn-3b KO mice develop adverse remodelling and reduced cardiac function. As a TF, Brn-3b regulates the expression of multiple target genes, including GLUT4, GSK3β, sonic hedgehog (SHH), cyclin D1 and CDK4, which have known functions in controlling metabolic processes but also participate in cardiac responses to stress or injury. Therefore, loss of Brn-3b and the resultant alterations in the expression of such genes could potentially provide the link between metabolic dysfunctions with adverse cardiovascular responses, which is seen in Brn-3b KO mutants. Since the loss of Brn-3b is associated with obesity, type II diabetes (T2DM) and altered cardiac responses to stress, this regulator may provide a new and important link for understanding how pathological changes arise in such endemic diseases.


2016 ◽  
Vol 32 (2) ◽  
pp. 89-100 ◽  
Author(s):  
Rene C. Adam ◽  
Elaine Fuchs

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kylie Hin-Man Mak ◽  
Yuk Man Lam ◽  
Ray Kit Ng

AbstractTrophoblast stem cell (TSC) is crucial to the formation of placenta in mammals. Histone demethylase JMJD2 (also known as KDM4) family proteins have been previously shown to support self-renewal and differentiation of stem cells. However, their roles in the context of the trophoblast lineage remain unclear. Here, we find that knockdown of Jmjd2b resulted in differentiation of TSCs, suggesting an indispensable role of JMJD2B/KDM4B in maintaining the stemness. Through the integration of transcriptome and ChIP-seq profiling data, we show that JMJD2B is associated with a loss of H3K36me3 in a subset of embryonic lineage genes which are marked by H3K9me3 for stable repression. By characterizing the JMJD2B binding motifs and other transcription factor binding datasets, we discover that JMJD2B forms a protein complex with AP-2 family transcription factor TFAP2C and histone demethylase LSD1. The JMJD2B–TFAP2C–LSD1 complex predominantly occupies active gene promoters, whereas the TFAP2C–LSD1 complex is located at putative enhancers, suggesting that these proteins mediate enhancer–promoter interaction for gene regulation. We conclude that JMJD2B is vital to the TSC transcriptional program and safeguards the trophoblast cell fate via distinctive protein interactors and epigenetic targets.


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