scholarly journals MEIS homeodomain proteins facilitate PARP1/ARTD1-mediated eviction of histone H1

2017 ◽  
Vol 216 (9) ◽  
pp. 2715-2729 ◽  
Author(s):  
Ann-Christin Hau ◽  
Britta Moyo Grebbin ◽  
Zsuzsa Agoston ◽  
Marie Anders-Maurer ◽  
Tamara Müller ◽  
...  

Pre–B-cell leukemia homeobox (PBX) and myeloid ecotropic viral integration site (MEIS) proteins control cell fate decisions in many physiological and pathophysiological contexts, but how these proteins function mechanistically remains poorly defined. Focusing on the first hours of neuronal differentiation of adult subventricular zone–derived stem/progenitor cells, we describe a sequence of events by which PBX-MEIS facilitates chromatin accessibility of transcriptionally inactive genes: In undifferentiated cells, PBX1 is bound to the H1-compacted promoter/proximal enhancer of the neuron-specific gene doublecortin (Dcx). Once differentiation is induced, MEIS associates with chromatin-bound PBX1, recruits PARP1/ARTD1, and initiates PARP1-mediated eviction of H1 from the chromatin fiber. These results for the first time link MEIS proteins to PARP-regulated chromatin dynamics and provide a mechanistic basis to explain the profound cellular changes elicited by these proteins.

2021 ◽  
Vol 7 (1) ◽  
pp. 37
Author(s):  
Mohammad N. Qasim ◽  
Ashley Valle Arevalo ◽  
Clarissa J. Nobile ◽  
Aaron D. Hernday

Candida albicans, a diploid polymorphic fungus, has evolved a unique heritable epigenetic program that enables reversible phenotypic switching between two cell types, referred to as “white” and “opaque”. These cell types are established and maintained by distinct transcriptional programs that lead to differences in metabolic preferences, mating competencies, cellular morphologies, responses to environmental signals, interactions with the host innate immune system, and expression of approximately 20% of genes in the genome. Transcription factors (defined as sequence specific DNA-binding proteins) that regulate the establishment and heritable maintenance of the white and opaque cell types have been a primary focus of investigation in the field; however, other factors that impact chromatin accessibility, such as histone modifying enzymes, chromatin remodelers, and histone chaperone complexes, also modulate the dynamics of the white-opaque switch and have been much less studied to date. Overall, the white-opaque switch represents an attractive and relatively “simple” model system for understanding the logic and regulatory mechanisms by which heritable cell fate decisions are determined in higher eukaryotes. Here we review recent discoveries on the roles of chromatin accessibility in regulating the C. albicans white-opaque phenotypic switch.


Author(s):  
Lucy LeBlanc ◽  
Nereida Ramirez ◽  
Jonghwan Kim

AbstractHippo effectors YAP and TAZ control cell fate and survival through various mechanisms, including transcriptional regulation of key genes. However, much of this research has been marked by conflicting results, as well as controversy over whether YAP and TAZ are redundant. A substantial portion of the discordance stems from their contradictory roles in stem cell self-renewal vs. differentiation and cancer cell survival vs. apoptosis. In this review, we present an overview of the multiple context-dependent functions of YAP and TAZ in regulating cell fate decisions in stem cells and organoids, as well as their mechanisms of controlling programmed cell death pathways in cancer.


Author(s):  
Emma Carley ◽  
Rachel K. Stewart ◽  
Abigail Zieman ◽  
Iman Jalilian ◽  
Diane. E. King ◽  
...  

AbstractWhile the mechanisms by which chemical signals control cell fate have been well studied, how mechanical inputs impact cell fate decisions are not well understood. Here, using the well-defined system of keratinocyte differentiation in the skin, we examine whether and how direct force transmission to the nucleus regulates epidermal cell fate. Using a molecular biosensor, we find that tension on the nucleus through Linker of Nucleoskeleton and Cytoskeleton (LINC) complexes requires integrin engagement in undifferentiated epidermal stem cells, and is released during differentiation concomitant with decreased tension on A-type lamins. LINC complex ablation in mice reveals that LINC complexes are required to repress epidermal differentiation in vivo and in vitro and influence accessibility of epidermal differentiation genes, suggesting that force transduction from engaged integrins to the nucleus plays a role in maintaining keratinocyte progenitors. This work reveals a direct mechanotransduction pathway capable of relaying adhesion-specific signals to regulate cell fate.


2018 ◽  
Vol 218 (1) ◽  
pp. 70-82 ◽  
Author(s):  
Sabrina Ladstätter ◽  
Kikuë Tachibana

The early embryo is the natural prototype for the acquisition of totipotency, which is the potential of a cell to produce a whole organism. Generation of a totipotent embryo involves chromatin reorganization and epigenetic reprogramming that alter DNA and histone modifications. Understanding embryonic chromatin architecture and how this is related to the epigenome and transcriptome will provide invaluable insights into cell fate decisions. Recently emerging low-input genomic assays allow the exploration of regulatory networks in the sparsely available mammalian embryo. Thus, the field of developmental biology is transitioning from microscopy to genome-wide chromatin descriptions. Ultimately, the prototype becomes a unique model for studying fundamental principles of development, epigenetic reprogramming, and cellular plasticity. In this review, we discuss chromatin reprogramming in the early mouse embryo, focusing on DNA methylation, chromatin accessibility, and higher-order chromatin structure.


Blood ◽  
2006 ◽  
Vol 107 (11) ◽  
pp. 4308-4316 ◽  
Author(s):  
Hyung Chan Suh ◽  
John Gooya ◽  
Katie Renn ◽  
Alan D. Friedman ◽  
Peter F. Johnson ◽  
...  

AbstractC/EBPα is an essential transcription factor required for myeloid differentiation. While C/EBPα can act as a cell fate switch to promote granulocyte differentiation in bipotential granulocyte-macrophage progenitors (GMPs), its role in regulating cell fate decisions in more primitive progenitors is not known. We found increased numbers of erythroid progenitors and erythroid cells in C/EBPα–/– fetal liver (FL). Also, enforced expression of C/EBPα in hematopoietic stem cells resulted in a loss of erythroid progenitors and an increase in myeloid cells by inhibition of erythroid development and inducing myeloid differentiation. Conditional expression of C/EBPα in murine erythroleukemia (MEL) cells induced myeloid-specific genes, while inhibiting erythroid-specific gene expression including erythropoietin receptor (EpoR), which suggests a novel mechanism to determine hematopoietic cell fate. Thus, C/EBPα functions in hematopoietic cell fate decisions by the dual actions of inhibiting erythroid and inducing myeloid gene expression in multipotential progenitors.


Science ◽  
2017 ◽  
Vol 356 (6345) ◽  
pp. 1379-1383 ◽  
Author(s):  
Marcin Zagorski ◽  
Yoji Tabata ◽  
Nathalie Brandenberg ◽  
Matthias P. Lutolf ◽  
Gašper Tkačik ◽  
...  

Like many developing tissues, the vertebrate neural tube is patterned by antiparallel morphogen gradients. To understand how these inputs are interpreted, we measured morphogen signaling and target gene expression in mouse embryos and chick ex vivo assays. From these data, we derived and validated a characteristic decoding map that relates morphogen input to the positional identity of neural progenitors. Analysis of the observed responses indicates that the underlying interpretation strategy minimizes patterning errors in response to the joint input of noisy opposing gradients. We reverse-engineered a transcriptional network that provides a mechanistic basis for the observed cell fate decisions and accounts for the precision and dynamics of pattern formation. Together, our data link opposing gradient dynamics in a growing tissue to precise pattern formation.


2018 ◽  
Author(s):  
Daniel Strebinger ◽  
Cédric Deluz ◽  
Elias T. Friman ◽  
Subashika Govindan ◽  
Andrea B. Alber ◽  
...  

AbstractSOX2 and OCT4 are pioneer transcription factors playing a key role in embryonic stem (ES) cell self-renewal and differentiation. However, how temporal fluctuations in their expression levels bias lineage commitment is unknown. Here we generated knock-in reporter fusion ES cell lines allowing to monitor endogenous SOX2 and OCT4 protein fluctuations in living cells and to determine their impact on mesendodermal and neuroectodermal commitment. We found that small differences in SOX2 and OCT4 levels impact cell fate commitment in G1 but not in S phase. Elevated SOX2 levels modestly increased neuroectodermal commitment and decreased mesendodermal commitment upon directed differentiation. In contrast, elevated OCT4 levels strongly biased ES cell towards both neuroectodermal and mesendodermal fates. Using ATAC-seq on ES cells gated for different endogenous SOX2 and OCT4 levels, we found that high OCT4 levels increased chromatin accessibility at differentiation-associated enhancers. This suggests that small endogenous fluctuations of pioneer transcription factors can bias cell fate decisions by concentration-dependent priming of differentiation-associated enhancers.


2021 ◽  
Author(s):  
Candice Byers ◽  
Catrina Spruce ◽  
Haley J. Fortin ◽  
Anne Czechanski ◽  
Steven C. Munger ◽  
...  

AbstractGenetically diverse pluripotent stem cells (PSCs) display varied, heritable responses to differentiation cues in the culture environment. By harnessing these disparities through derivation of embryonic stem cells (ESCs) from the BXD mouse genetic reference panel, along with C57BL/6J (B6) and DBA/2J (D2) parental strains, we demonstrate genetically determined biases in lineage commitment and identify major regulators of the pluripotency epigenome. Upon transition to formative pluripotency using epiblast-like cells (EpiLCs), B6 quickly dissolves naïve networks adopting gene expression modules indicative of neuroectoderm lineages; whereas D2 retains aspects of naïve pluripotency with little bias in differentiation. Genetic mapping identifies 6 major trans-acting loci co-regulating chromatin accessibility and gene expression in ESCs and EpiLCs, indicating a common regulatory system impacting cell state transition. These loci distally modulate occupancy of pluripotency factors, including TRIM28, P300, and POU5F1, at hundreds of regulatory elements. One trans-acting locus on Chr 12 primarily impacts chromatin accessibility in ESCs; while in EpiLCs the same locus subsequently influences gene expression, suggesting early chromatin priming. Consequently, the distal gene targets of this locus are enriched for neurogenesis genes and were more highly expressed when cells carried B6 haplotypes at this Chr 12 locus, supporting genetic regulation of biases in cell fate. Spontaneous formation of embryoid bodies validated this with B6 showing a propensity towards neuroectoderm differentiation and D2 towards definitive endoderm, confirming the fundamental importance of genetic variation influencing cell fate decisions.


Development ◽  
1997 ◽  
Vol 124 (6) ◽  
pp. 1203-1213 ◽  
Author(s):  
P. Balint-Kurti ◽  
G. Ginsburg ◽  
O. Rivero-Lezcano ◽  
A.R. Kimmel

rZIP is an approx. 32 kDa, multi-domain protein of Dictyostelium discoideum whose structural motifs include a RING (zinc-binding) domain, a leucine zipper, a glutamine repeat, an SH3-binding region and a consensus phosphorylation site for MAP kinase. In vitro, rZIP forms homodimers and interacts specifically with the SH3 domain(s) of the Nck adaptor protein. rZIP is expressed maximally during cell differentiation at approximately equivalent levels in all cells. Disruption of the rZIP gene rzpA results in altered cellular aggregation, impaired slug migration, and aberrant patterning of prespore and prestalk cells, the major progenitor classes. In rzpA- strains, prespore-specific genes are overexpressed and prestalk expression zones are reduced. Conversely, constitutive overexpression of rzpA markedly decreases prespore-specific gene expression and significantly increases the expression of prestalk-specific genes. Further, induced transdifferentiation of prespore cells into prestalk cells is inhibited in rzpA-slugs. In light of these patterning defects, we suggest that the RING/zipper protein rZIP plays an important role in early cell fate decisions in Dictyostelium, acting as a positive regulator of prestalk differentiation and an inhibitor of prespore differentiation.


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