scholarly journals Genetic and epigenetic regulation of zebrafish intestinal development

Epigenomes ◽  
2018 ◽  
Vol 2 (4) ◽  
pp. 19 ◽  
Author(s):  
Bilge San ◽  
Marco Aben ◽  
Dei M. Elurbe ◽  
Kai Voeltzke ◽  
Marjo J. den Broeder ◽  
...  

Many regulatory pathways are conserved in the zebrafish intestine compared to mammals, rendering it a strong model to study intestinal development. However, the (epi)genetic regulation of zebrafish intestinal development remains largely uncharacterized. We performed RNA-sequencing and chromatin immunoprecipitation (ChIP)-sequencing for activating (H3K4me3) and repressive (H3K27me3) chromatin marks on isolated intestines at 5, 7, and 9 days post-fertilization (dpf), during which zebrafish transit from yolk dependence to external feeding. RNA-sequencing showed the enrichment of metabolic maintenance genes at all time points and a significant increase in lipid metabolism between 5 and 9 dpf. A strong correlation was observed between gene expression and presence of chromatin marks on gene promoters; H3K4me3-marked genes were expressed higher than H3K27m3-marked genes. Next, we studied a key epigenetic player, Enhancer of zeste homolog 2 (Ezh2). Ezh2 places the repressive H3K27me3 mark on the genome and is highly conserved in vertebrates. We used the nonsense mutant allele ezh2(hu5670) to study the effect of ezh2 loss on intestinal development. These mutants survived gastrulation and died around 11 dpf, showing severe morphological defects in the intestine and liver, accompanied by decreased intestinal (fabp2) and hepatic (fabp10a) marker expressions. Our results suggest that Ezh2 is essential for proper intestinal tissue maintenance and overall survival.

Cancers ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 25 ◽  
Author(s):  
Gurubharathi Bhuvanalakshmi ◽  
Naisarg Gamit ◽  
Manasi Patil ◽  
Frank Arfuso ◽  
Gautam Sethi ◽  
...  

Background: Chemotherapeutic resistance of glioblastoma has been attributed to a self-renewing subpopulation, the glioma stem cells (GSCs), which is known to be maintained by the Wnt β−catenin pathway. Our previous findings demonstrated that exogeneous addition of the Wnt antagonist, secreted fizzled-related protein 4 (sFRP4) hampered stem cell properties in GSCs. Methods: To understand the molecular mechanism of sFRP4, we overexpressed sFRP4 (sFRP4 OE) in three human glioblastoma cell lines U87MG, U138MG, and U373MG. We also performed chromatin immunoprecipitation (ChIP) sequencing of sFRP4 OE and RNA sequencing of sFRP4 OE and sFRP4 knocked down U87 cells. Results: We observed nuclear localization of sFRP4, suggesting an unknown nuclear role. ChIP-sequencing of sFRP4 pulldown DNA revealed a homeobox Cphx1, related to the senescence regulator ETS proto-oncogene 2 (ETS2). Furthermore, miRNA885, a p53-mediated apoptosis inducer, was upregulated in sFRP4 OE cells. RNA sequencing analysis suggested that sFRP4-mediated apoptosis is via the Fas-p53 pathway by activating the Wnt calcium and reactive oxygen species pathways. Interestingly, sFRP4 OE cells had decreased stemness, but when knocked down in multipotent mesenchymal stem cells, pluripotentiality was induced and the Wnt β-catenin pathway was upregulated. Conclusions: This study unveils a novel nuclear role for sFRP4 to promote apoptosis by a possible activation of DNA damage machinery in glioblastoma.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Xiaofeng Liu ◽  
Jiacai Chen ◽  
Xiaolan Zhang

AbstractCucumber (Cucumis sativus L.) is an important vegetable crop species with great economic value. Shoot architecture determines the visual appearance of plants and has a strong impact on crop management and yield. Unlike most model plant species, cucumber undergoes vegetative growth and reproductive growth simultaneously, in which leaves are produced from the shoot apical meristem and flowers are generated from leaf axils, during the majority of its life, a feature representative of the Cucurbitaceae family. Despite substantial advances achieved in understanding the regulation of plant form in Arabidopsis thaliana, rice, and maize, our understanding of the mechanisms controlling shoot architecture in Cucurbitaceae crop species is still limited. In this review, we focus on recent progress on elucidating the genetic regulatory pathways underlying the determinant/indeterminant growth habit, leaf shape, branch outgrowth, tendril identity, and vine length determination in cucumber. We also discuss the potential of applying biotechnology tools and resources for the generation of ideal plant types with desired architectural features to improve cucumber productivity and cultivation efficiency.


Development ◽  
1998 ◽  
Vol 125 (10) ◽  
pp. 1803-1813 ◽  
Author(s):  
L.C. Kadyk ◽  
J. Kimble

The Caenorhabditis elegans germline is composed of mitotically dividing cells at the distal end that give rise to meiotic cells more proximally. Specification of the distal region as mitotic relies on induction by the somatic distal tip cell and the glp-1 signal transduction pathway. However, the genetic control over the transition from mitosis to meiosis is not understood. In this paper, we report the identification of a gene, gld-2, that has at least two functions in germline development. First, gld-2 is required for normal progression through meiotic prophase. Second, gld-2 promotes entry into meiosis from the mitotic cell cycle. With respect to this second function, gld-2 appears to be functionally redundant with a previously described gene, gld-1 (Francis, R., Barton, M. K., Kimble, J. and Schedl, T. (1995) Genetics 139, 579–606). Germ cells in gld-1(o) and gld-2 single mutants enter meiosis at the normal time, but germ cells in gld-2 gld-1(o) double mutants do not enter meiosis. Instead, the double mutant germline is mitotic throughout and forms a large tumor. We suggest that gld-1 and gld-2 define two independent regulatory pathways, each of which can be sufficient for entry into meiosis. Epistasis analyses show that gld-1 and gld-2 work downstream of the glp-1 signal transduction pathway. Therefore, we hypothesize that glp-1 promotes proliferation by inhibiting the meiosis-promoting functions of gld-1 and gld-2.


Author(s):  
Tongbin Wu ◽  
Zhengyu Liang ◽  
Zengming Zhang ◽  
Canzhao Liu ◽  
Lunfeng Zhang ◽  
...  

Background: Left ventricular noncompaction cardiomyopathy (LVNC) was discovered half a century ago as a cardiomyopathy with excessive trabeculation and a thin ventricular wall. In the decades since, numerous studies have demonstrated that LVNC primarily impacts left ventricles (LVs), and is often associated with LV dilation and dysfunction. However, owing in part to the lack of suitable mouse models that faithfully mirror the selective LV vulnerability in patients, mechanisms underlying susceptibility of LV to dilation and dysfunction in LVNC remain unknown. Genetic studies have revealed that deletions and mutations in PRDM16 cause LVNC, but previous conditional Prdm16 knockout mouse models do not mirror the LVNC phenotype in patients, and importantly, the underlying molecular mechanisms by which PRDM16 deficiency causes LVNC are still unclear. Methods: Prdm16 cardiomyocyte (CM)-specific knockout ( Prdm16 cKO ) mice were generated and analyzed for cardiac phenotypes. RNA sequencing and ChIP sequencing were performed to identify direct transcriptional targets of PRDM16 in CMs. Single cell RNA sequencing in combination with Spatial Transcriptomics were employed to determine CM identity at single cell level. Results: CM-specific ablation of Prdm16 in mice caused LV-specific dilation and dysfunction, as well as biventricular noncompaction, which fully recapitulated LVNC in patients. Mechanistically, PRDM16 functioned as a compact myocardium-enriched transcription factor, which activated compact myocardial genes while repressing trabecular myocardial genes in LV compact myocardium. Consequently, Prdm16 cKO LV compact myocardial CMs shifted from their normal transcriptomic identity to a transcriptional signature resembling trabecular myocardial CMs and/or neurons. Chamber-specific transcriptional regulation by PRDM16 was in part due to its cooperation with LV-enriched transcription factors Tbx5 and Hand1. Conclusions: These results demonstrate that disruption of proper specification of compact CM may play a key role in the pathogenesis of LVNC. They also shed light on underlying mechanisms of LV-restricted transcriptional program governing LV chamber growth and maturation, providing a tangible explanation for the susceptibility of LV in a subset of LVNC cardiomyopathies.


Author(s):  
Roxanne E. Diaz ◽  
Aurore Sanchez ◽  
Véronique Anton Le Berre ◽  
Jean-Yves Bouet

2013 ◽  
Vol 33 (9) ◽  
pp. 1819-1829 ◽  
Author(s):  
Zhigang Tu ◽  
Xinying Zhuang ◽  
Yong-Gang Yao ◽  
Rugang Zhang

Cellular senescence is an important tumor suppression mechanism. We have previously reported that both oncogene-induced dissociation of BRCA1 from chromatin and BRCA1 knockdown itself drive senescence by promoting formation of s enescence- a ssociated h eterochromatin f oci (SAHF). However, the molecular mechanism by which BRCA1 regulates SAHF formation and senescence is unclear. BRG1 is a chromatin-remodeling factor that interacts with BRCA1 and pRB. Here we show that BRG1 is required for SAHF formation and senescence induced by oncogenic RAS or BRCA1 loss. The interaction between BRG1 and BRCA1 is disrupted during senescence. This correlates with an increased level of chromatin-associated BRG1 in senescent cells. BRG1 knockdown suppresses the formation of SAHF and senescence, while it has no effect on BRCA1 chromatin dissociation induced by oncogenic RAS, indicating that BRG1 functions downstream of BRCA1 chromatin dissociation. Furthermore, BRG1 knockdown inhibits SAHF formation and senescence induced by BRCA1 knockdown. Conversely, BRG1 overexpression drives SAHF formation and senescence in a DNA damage-independent manner. This effect depends upon BRG1's chromatin-remodeling activity as well as the interaction between BRG1 and pRB. Indeed, the interaction between BRG1 and pRB is enhanced during senescence. Chromatin immunoprecipitation analysis revealed that BRG1's association with the human CDKN2A and CDKN1A gene promoters was enhanced during senescence induced by oncogenic RAS or BRCA1 knockdown. Consistently, knockdown of pRB, p21 CIP1 , and p16 INK4a , but not p53, suppressed SAHF formation induced by BRG1. Together, these studies reveal the molecular underpinning by which BRG1 acts downstream of BRCA1 to promote SAHF formation and senescence.


2020 ◽  
Author(s):  
Shi-lei Liu ◽  
Xiang-song Wu ◽  
Feng-nan Li ◽  
Wen-yan Yao ◽  
Zi-you Wu ◽  
...  

Abstract Background: Estrogen-related receptor alpha (ERRα), an orphan nuclear receptor, was reported to be highly associated with the progression and tumorigenesis of several human malignancies. However, the biological role and underlying molecular mechanisms of ERRα in pancreatic cancer (PC) remain unknown.Methods: The expression of ERRα in PC tissues was determined by qRT-PCR and immunohistochemistry. A series of in vitro and in vivo assays were performed to investigate the function of ERRα and Plasminogen activator inhibitor 1 (PAI1) in tumorigenesis in PC cells. The relationship between ERRα and PAI1 was identified by RNA sequencing, Chromatin immunoprecipitation and dual-luciferase reporter assays. The effects of ERRα on the MEK/ERK signaling pathway were determined by western blotting and rescue assays using ERK inhibitor GDC-0994.Results: ERRα was significantly overexpressed in PC tissues and cell lines. Its high expression was correlated with tumor size, distant metastasis, TNM stage, tumor differentiation and poor prognosis of PC. Subsequent functional assays showed that ERRα promoted PC cell proliferation, tumor growth, as well as migration and invasion via activating the epithelial-mesenchymal transition. In addition, knockdown of ERRα induced apoptosis and G0/G1 cell cycle arrest in PC cells. PAI1 was identified by RNA sequencing, knockdown of which could suppress the cell proliferation, migration and invasion that promoted by ERRα overexpression. Further mechanistic investigation using chromatin immunoprecipitation and dual-luciferase reporter assays revealed that ERRα could bind to the PAI1 promoter region and transcriptionally enhance PAI1 expression. Moreover, our data indicated that ERRα played its oncogenic role in PC via activating the MEK/ERK pathway.Conclusions: Our study demonstrates that ERRα promotes PC progression by enhancing the transcription of PAI1 and activation of the MEK/ERK pathway, pointing to ERRα as a novel diagnostic and therapeutic target for PC.


F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 54 ◽  
Author(s):  
Marco-Antonio Mendoza-Parra ◽  
Vincent Saravaki ◽  
Pierre-Etienne Cholley ◽  
Matthias Blum ◽  
Benjamin Billoré ◽  
...  

We have established a certification system for antibodies to be used in chromatin immunoprecipitation assays coupled to massive parallel sequencing (ChIP-seq). This certification comprises a standardized ChIP procedure and the attribution of a numerical quality control indicator (QCi) to biological replicate experiments. The QCi computation is based on a universally applicable quality assessment that quantitates the global deviation of randomly sampled subsets of ChIP-seq dataset with the original genome-aligned sequence reads. Comparison with a QCi database for >28,000 ChIP-seq assays were used to attribute quality grades (ranging from ‘AAA’ to ‘DDD’) to a given dataset. In the present report we used the numerical QC system to assess the factors influencing the quality of ChIP-seq assays, including the nature of the target, the sequencing depth and the commercial source of the antibody.  We have used this approach specifically to certify mono and polyclonal antibodies obtained from Active Motif directed against the histone modification marks H3K4me3, H3K27ac and H3K9ac for ChIP-seq. The antibodies received the grades AAA to BBC (www.ngs-qc.org). We propose to attribute such quantitative grading of all antibodies attributed with the label “ChIP-seq grade”.


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