scholarly journals Loss of PIKfyve Causes Transdifferentiation of Dictyostelium Spores Into Basal Disc Cells

2021 ◽  
Vol 9 ◽  
Author(s):  
Yoko Yamada ◽  
Gillian Forbes ◽  
Qingyou Du ◽  
Takefumi Kawata ◽  
Pauline Schaap
Keyword(s):  
Gene Expression ◽  
Cell Fate ◽  
Specific Gene ◽  
Basal Disc ◽  
Disc Cells ◽  
Cell Type Specific ◽  
Camp Induction ◽  
Endosomal System ◽  
Spore Coat Protein

The 1-phosphatidylinositol-3-phosphate 5-kinase PIKfyve generates PtdIns3,5P2 on late phagolysosomes, which by recruiting the scission protein Atg18, results in their fragmentation in the normal course of endosome processing. Loss of PIKfyve function causes cellular hypervacuolization in eukaryotes and organ failure in humans. We identified pikfyve as the defective gene in a Dictyostelium mutant that failed to form spores. The amoebas normally differentiated into prespore cells and initiated spore coat protein synthesis in Golgi-derived prespore vesicles. However, instead of exocytosing, the prespore vesicles fused into the single vacuole that typifies the stalk and basal disc cells that support the spores. This process was accompanied by stalk wall biosynthesis, loss of spore gene expression and overexpression of ecmB, a basal disc and stalk-specific gene, but not of the stalk-specific genes DDB_G0278745 and DDB_G0277757. Transdifferentiation of prespore into stalk-like cells was previously observed in mutants that lack early autophagy genes, like atg5, atg7, and atg9. However, while autophagy mutants specifically lacked cAMP induction of prespore gene expression, pikfyve− showed normal early autophagy and prespore induction, but increased in vitro induction of ecmB. Combined, the data suggest that the Dictyostelium endosomal system influences cell fate by acting on cell type specific gene expression.

scholarly journals Small Interfering RNA–Mediated Suppression of Fas Modulate Apoptosis and Proliferation in Rat Intervertebral Disc Cells

2017 ◽  
Vol 11 (5) ◽  
pp. 686-693
Author(s):  
Jong-Beom Park ◽  
Chanjoo Park
Keyword(s):  
Gene Expression ◽  
Mammalian Cells ◽  
Small Interfering Rna ◽  
Mrna Level ◽  
Serum Deprivation ◽  
Specific Gene ◽  
Disc Cells ◽  
Fetal Bovine ◽  
Interfering Rna

<sec><title>Study Design</title><p><italic>In vitro</italic> cell culture model.</p></sec><sec><title>Purpose</title><p>To investigate the effect of small interfering RNA (siRNA) on Fas expression, apoptosis, and proliferation in serum-deprived rat disc cells.</p></sec><sec><title>Overview of Literature</title><p>Synthetic siRNA can trigger an RNA interference (RNAi) response in mammalian cells and precipitate the inhibition of specific gene expression. However, the potential utility of siRNA technology in downregulation of specific genes associated with disc cell apoptosis remains unclear.</p></sec><sec><title>Methods</title><p>Rat disc cells were isolated and cultured in the presence of either 10% fetal bovine serum (FBS) (normal control) or 0% FBS (serum deprivation to induce apoptosis) for 48 hours. Fas expression, apoptosis, and proliferation were determined. Additionally, siRNA oligonucleotides against Fas (Fas siRNA) were transfected into rat disc cells to suppress Fas expression. Changes in Fas expression were assessed by reverse transcription-polymerase chain reaction and semiquantitatively analyzed using densitometry. The effect of Fas siRNA on apoptosis and proliferation of rat disc cells were also determined. Negative siRNA and transfection agent alone (Mock) were used as controls.</p></sec><sec><title>Results</title><p>Serum deprivation increased apoptosis by 40.3% (<italic>p</italic>&lt;0.001), decreased proliferation by 45.3% (<italic>p</italic>&lt;0.001), and upregulated Fas expression. Additionally, Fas siRNA suppressed Fas expression in serum-deprived cultures, with 68.5% reduction at the mRNA level compared to the control cultures (<italic>p</italic>&lt;0.001). Finally, Fas siRNA–mediated suppression of Fas expression significantly inhibited apoptosis by 9.3% and increased proliferation by 21% in serum-deprived cultures (<italic>p</italic>&lt;0.05 for both).</p></sec><sec><title>Conclusions</title><p>The observed dual positive effect of Fas siRNA might be a powerful therapeutic approach for disc degeneration by suppression of harmful gene expression.</p></sec>

scholarly journals Super-Enhancers and CTCF in Early Embryonic Cell Fate Decisions

2021 ◽  
Vol 9 ◽  
Author(s):  
Puja Agrawal ◽  
Sridhar Rao
Keyword(s):  
Gene Expression ◽  
Cell Fate ◽  
Critical Role ◽  
Regulatory Elements ◽  
Specific Gene ◽  
Cell Type ◽  
Mammalian Development ◽  
Cell Fate Decisions ◽  
Cell Type Specific ◽  
Early Mammalian Development

Cell fate decisions are the backbone of many developmental and disease processes. In early mammalian development, precise gene expression changes underly the rapid division of a single cell that leads to the embryo and are critically dependent on autonomous cell changes in gene expression. To understand how these lineage specifications events are mediated, scientists have had to look past protein coding genes to the cis regulatory elements (CREs), including enhancers and insulators, that modulate gene expression. One class of enhancers, termed super-enhancers, is highly active and cell-type specific, implying their critical role in modulating cell-type specific gene expression. Deletion or mutations within these CREs adversely affect gene expression and development and can cause disease. In this mini-review we discuss recent studies describing the potential roles of two CREs, enhancers and binding sites for CTCF, in early mammalian development.

Characterization of a Megakaryocyte-Specific Enhancer of the Key Hemopoietic Transcription Factor GATA1.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 834-834
Author(s):  
Boris Guyot ◽  
Kasumi Murai ◽  
Yuko Fujiwara ◽  
Veronica Valverde-Garduno ◽  
Michele Hammett ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Dna Binding ◽  
Transgenic Mice ◽  
Cell Fate ◽  
Red Cells ◽  
Specific Gene ◽  
Cell Fate Decisions

Abstract Specification and differentiation of the megakaryocyte and erythroid lineages from a common bipotential progenitor provides a well-studied model to dissect binary cell fate decisions. To understand how the distinct megakaryocyte- and erythroid-specific gene programs arise, we have examined the transcriptional regulation of the transcription factor GATA1, that is required for normal maturation of these two lineages. Megakaryocyte- and erythroid-specific mouse (m)GATA1 expression requires the mGata1 enhancer mHS-3.5. Within mHS-3.5, we previously showed that the 3′ 179 base pairs (bp) of mHS-3.5 are required for megakaryocyte but not red cell expression. Here, we show that mHS-3.5 binds key hemopoietic transcription factors in vivo (GATA1, SCL/TAL-1) and is required to maintain histone acetylation in the mGata1 locus in primary megakaryocytes. When deletional constructs containing mHS-3.5 were used to direct GATA1-LacZ reporter gene expression in transgenic mice, a 25 bp element within the 3′ 179bp in mHS-3.5, was critical for megakaryocyte expression. In vitro three uncharacterized DNA-binding activities A, B and C bind to the core of the 25 bp element, and these binding sites are conserved through evolution. Of these, only activity B is present in primary megakaryocytes but not red cells. Furthermore, mutation analysis in transgenic mice reveals that activity B is required for megakaryocyte-specific enhancer function. Bioinformatic analysis shows that sequence corresponding to the binding site for activity B is a previously unrecognised motif present in the cis-elements of other megakaryocyte-specific genes. In summary, we have identified a motif and a DNA-binding activity that are likely to be important in directing a megakaryocyte gene expression program distinct from that in red cells.

scholarly journals Enhancer priming by H3K4 methyltransferase MLL4 controls cell fate transition

2016 ◽  
Vol 113 (42) ◽  
pp. 11871-11876 ◽  
Author(s):  
Chaochen Wang ◽  
Ji-Eun Lee ◽  
Binbin Lai ◽  
Todd S. Macfarlan ◽  
Shiliyang Xu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
Cell Fate ◽  
Control Cell ◽  
Embryonic Stem ◽  
Specific Gene ◽  
Cell Identity ◽  
Identity Maintenance ◽  
Cell Type Specific ◽  
Induced Pluripotent

Transcriptional enhancers control cell-type–specific gene expression. Primed enhancers are marked by histone H3 lysine 4 (H3K4) mono/di-methylation (H3K4me1/2). Active enhancers are further marked by H3K27 acetylation (H3K27ac). Mixed-lineage leukemia 4 (MLL4/KMT2D) is a major enhancer H3K4me1/2 methyltransferase with functional redundancy with MLL3 (KMT2C). However, its role in cell fate maintenance and transition is poorly understood. Here, we show in mouse embryonic stem cells (ESCs) that MLL4 associates with, but is surprisingly dispensable for the maintenance of, active enhancers of cell-identity genes. As a result, MLL4 is dispensable for cell-identity gene expression and self-renewal in ESCs. In contrast, MLL4 is required for enhancer-binding of H3K27 acetyltransferase p300, enhancer activation, and induction of cell-identity genes during ESC differentiation. MLL4 protein, rather than MLL4-mediated H3K4 methylation, controls p300 recruitment to enhancers. We also show that, in somatic cells, MLL4 is dispensable for maintaining cell identity but essential for reprogramming into induced pluripotent stem cells. These results indicate that, although enhancer priming by MLL4 is dispensable for cell-identity maintenance, it controls cell fate transition by orchestrating p300-mediated enhancer activation.

scholarly journals The Interplay Between Chromatin Architecture and Lineage-Specific Transcription Factors and the Regulation of Rag Gene Expression

2021 ◽  
Vol 12 ◽  
Author(s):  
Kazuko Miyazaki ◽  
Masaki Miyazaki
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Cell Fate ◽  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Specific Gene ◽  
Cell Type ◽  
Cell Fate Decisions ◽  
Chromatin Architecture ◽  
Cell Type Specific

Cell type-specific gene expression is driven through the interplay between lineage-specific transcription factors (TFs) and the chromatin architecture, such as topologically associating domains (TADs), and enhancer-promoter interactions. To elucidate the molecular mechanisms of the cell fate decisions and cell type-specific functions, it is important to understand the interplay between chromatin architectures and TFs. Among enhancers, super-enhancers (SEs) play key roles in establishing cell identity. Adaptive immunity depends on the RAG-mediated assembly of antigen recognition receptors. Hence, regulation of the Rag1 and Rag2 (Rag1/2) genes is a hallmark of adaptive lymphoid lineage commitment. Here, we review the current knowledge of 3D genome organization, SE formation, and Rag1/2 gene regulation during B cell and T cell differentiation.

Serial analysis of gene expression (SAGE) during porcine embryo development

2004 ◽  
Vol 16 (2) ◽  
pp. 87 ◽  
Author(s):  
Le Ann Blomberg ◽  
Kurt A. Zuelke
Keyword(s):  
Gene Expression ◽  
Functional Genomics ◽  
Embryo Development ◽  
Molecular Mechanisms ◽  
Physiological Role ◽  
Transgenic Animals ◽  
Specific Gene ◽  
Research Strategies

Functional genomics provides a powerful means for delving into the molecular mechanisms involved in pre-implantation development of porcine embryos. High rates of embryonic mortality (30%), following either natural mating or artificial insemination, emphasise the need to improve the efficiency of reproduction in the pig. The poor success rate of live offspring from in vitro-manipulated pig embryos also hampers efforts to generate transgenic animals for biotechnology applications. Previous analysis of differential gene expression has demonstrated stage-specific gene expression for in vivo-derived embryos and altered gene expression for in vitro-derived embryos. However, the methods used to date examine relatively few genes simultaneously and, thus, provide an incomplete glimpse of the physiological role of these genes during embryogenesis. The present review will focus on two aspects of applying functional genomics research strategies for analysing the expression of genes during elongation of pig embryos between gestational day (D) 11 and D12. First, we compare and contrast current methodologies that are being used for gene discovery and expression analysis during pig embryo development. Second, we establish a paradigm for applying serial analysis of gene expression as a functional genomics tool to obtain preliminary information essential for discovering the physiological mechanisms by which distinct embryonic phenotypes are derived.

Cell shape and gene expression in human intervertebral disc cells: in vitro tissue engineering studies

2003 ◽  
Vol 78 (2) ◽  
pp. 109-117 ◽  
Author(s):  
He Gruber ◽  
Ja Ingram ◽  
K Leslie ◽  
Hj Norton ◽  
En Hanley Jr
Keyword(s):  
Gene Expression ◽  
Tissue Engineering ◽  
Intervertebral Disc ◽  
Cell Shape ◽  
Engineering Studies ◽  
Disc Cells

scholarly journals A Dual Role for Oncostatin M Signaling in the Differentiation and Death of Mammary Epithelial Cells in Vivo

2008 ◽  
Vol 22 (12) ◽  
pp. 2677-2688 ◽  
Author(s):  
Paul G. Tiffen ◽  
Nader Omidvar ◽  
Nuria Marquez-Almuina ◽  
Dawn Croston ◽  
Christine J. Watson ◽  
...  
Keyword(s):  
Gene Expression ◽  
Epithelial Cell ◽  
Epithelial Cells ◽  
Mammary Epithelial Cells ◽  
Mammary Epithelial ◽  
Oncostatin M ◽  
Specific Gene ◽  
Mammary Involution

Abstract Recent studies in breast cancer cell lines have shown that oncostatin M (OSM) not only inhibits proliferation but also promotes cell detachment and enhances cell motility. In this study, we have looked at the role of OSM signaling in nontransformed mouse mammary epithelial cells in vitro using the KIM-2 mammary epithelial cell line and in vivo using OSM receptor (OSMR)-deficient mice. OSM and its receptor were up-regulated approximately 2 d after the onset of postlactational mammary regression, in response to leukemia inhibitory factor (LIF)-induced signal transducer and activator of transcription-3 (STAT3). This resulted in sustained STAT3 activity, increased epithelial apoptosis, and enhanced clearance of epithelial structures during the remodeling phase of mammary involution. Concurrently, OSM signaling precipitated the dephosphorylation of STAT5 and repressed expression of the milk protein genes β-casein and whey acidic protein (WAP). Similarly, during pregnancy, OSM signaling suppressed β-casein and WAP gene expression. In vitro, OSM but not LIF persistently down-regulated phosphorylated (p)-STAT5, even in the continued presence of prolactin. OSM also promoted the expression of metalloproteinases MMP3, MMP12, and MMP14, which, in vitro, were responsible for OSM-specific apoptosis. Thus, the sequential activation of IL-6-related cytokines during mammary involution culminates in an OSM-dependent repression of epithelial-specific gene expression and the potentiation of epithelial cell extinction mediated, at least in part, by the reciprocal regulation of p-STAT5 and p-STAT3.

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