scholarly journals Regulation of gene expression by the APP family in the adult cerebral cortex

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Hye Ji Cha ◽  
Jie Shen ◽  
Jongkyun Kang

AbstractAmyloid precursor protein (APP) is associated with both familial and sporadic forms of Alzheimer’s disease. APP has two homologs, amyloid precursor-like protein 1 and 2 (APLP1 and APLP2), and they have functional redundancy. APP intracellular c-terminal domain (AICD), produced by sequential α- or β- and γ-secretase cleavages, is thought to control gene expression, similarly as the ICD of Notch. To investigate the role of APP family in transcriptional regulation, we examined gene expression changes in the cerebral cortex of APP/APLP1/APLP2 conditional triple knockout (cTKO) mice, in which APP family members are selectively inactivated in excitatory neurons of the postnatal forebrain. Of the 12 previously reported AICD target genes, only Nep and Npas4 mRNA levels were significantly reduced in the cerebral cortex of cTKO mice, compared to littermate controls. We further examined global transcriptional changes by RNA-seq and identified 189 and 274 differentially expressed genes in the neocortex and hippocampus, respectively, of cTKO mice relative to controls. Gene Ontology analysis indicated that these genes are involved in a variety of cellular functions, including extracellular organization, learning and memory, and ion channels. Thus, inactivation of APP family alters transcriptional profiles of the cerebral cortex and affects wide-ranging molecular pathways.

2019 ◽  
Vol 84 (6) ◽  
pp. 233-239
Author(s):  
Xu Hui ◽  
Hisham Al-Ward ◽  
Fahmi Shaher ◽  
Chun-Yang Liu ◽  
Ning Liu

<b><i>Background:</i></b> MicroRNAs (miRNAs) represent a group of non-coding RNAs measuring 19–23 nucleotides in length and are recognized as powerful molecules that regulate gene expression in eukaryotic cells. miRNAs stimulate the post-transcriptional regulation of gene expression via direct or indirect mechanisms. <b><i>Summary:</i></b> miR-210 is highly upregulated in cells under hypoxia, thereby revealing its significance to cell endurance. Induction of this mRNA expression is an important feature of the cellular low-oxygen response and the most consistent and vigorous target of HIF. <b><i>Key Message:</i></b> miR-210 is involved in many cellular functions under the effect of HIF-1α, including the cell cycle, DNA repair, immunity and inflammation, angiogenesis, metabolism, and macrophage regulation. It also plays an important regulatory role in T-cell differentiation and stimulation.


2020 ◽  
Author(s):  
Rwik Sen ◽  
Ezra Lencer ◽  
Elizabeth A. Geiger ◽  
Kenneth L. Jones ◽  
Tamim H. Shaikh ◽  
...  

AbstractCongenital Heart Defects (CHDs) are the most common form of birth defects, observed in 4-10/1000 live births. CHDs result in a wide range of structural and functional abnormalities of the heart which significantly affect quality of life and mortality. CHDs are often seen in patients with mutations in epigenetic regulators of gene expression, like the genes implicated in Kabuki syndrome – KMT2D and KDM6A, which play important roles in normal heart development and function. Here, we examined the role of two epigenetic histone modifying enzymes, KMT2D and KDM6A, in the expression of genes associated with early heart and neural crest cell (NCC) development. Using CRISPR/Cas9 mediated mutagenesis of kmt2d, kdm6a and kdm6al in zebrafish, we show cardiac and NCC gene expression is reduced, which correspond to affected cardiac morphology and reduced heart rates. To translate our results to a human pathophysiological context and compare transcriptomic targets of KMT2D and KDM6A across species, we performed RNA sequencing (seq) of lymphoblastoid cells from Kabuki Syndrome patients carrying mutations in KMT2D and KDM6A. We compared the human RNA-seq datasets with RNA-seq datasets obtained from mouse and zebrafish. Our comparative interspecies analysis revealed common targets of KMT2D and KDM6A, which are shared between species, and these target genes are reduced in expression in the zebrafish mutants. Taken together, our results show that KMT2D and KDM6A regulate common and unique genes across humans, mice, and zebrafish for early cardiac and overall development that can contribute to the understanding of epigenetic dysregulation in CHDs.


Endocrinology ◽  
2012 ◽  
Vol 153 (6) ◽  
pp. 2919-2928 ◽  
Author(s):  
Arturo Hernandez ◽  
Beatriz Morte ◽  
Mónica M. Belinchón ◽  
Ainhoa Ceballos ◽  
Juan Bernal

Thyroid hormones regulate brain development and function through the control of gene expression, mediated by binding of T3 to nuclear receptors. Brain T3 concentration is tightly controlled by homeostatic mechanisms regulating transport and metabolism of T4 and T3. We have examined the role of the inactivating enzyme type 3 deiodinase (D3) in the regulation of 43 thyroid hormone-dependent genes in the cerebral cortex of 30-d-old mice. D3 inactivation increased slightly the expression of two of 22 positively regulated genes and significantly decreased the expression of seven of 21 negatively regulated genes. Administration of high doses of T3 led to significant changes in the expression of 12 positive genes and three negative genes in wild-type mice. The response to T3 treatment was enhanced in D3-deficient mice, both in the number of genes and in the amplitude of the response, demonstrating the role of D3 in modulating T3 action. Comparison of the effects on gene expression observed in D3 deficiency with those in hypothyroidism, hyperthyroidism, and type 2 deiodinase (D2) deficiency revealed that the negative genes are more sensitive to D2 and D3 deficiencies than the positive genes. This observation indicates that, in normal physiological conditions, D2 and D3 play critical roles in maintaining local T3 concentrations within a very narrow range. It also suggests that negatively and positively regulated genes do not have the same physiological significance or that their regulation by thyroid hormone obeys different paradigms at the molecular or cellular levels.


Endocrinology ◽  
2014 ◽  
Vol 155 (10) ◽  
pp. 3781-3792 ◽  
Author(s):  
Mounia Heddad Masson ◽  
Caroline Poisson ◽  
Audrey Guérardel ◽  
Aline Mamin ◽  
Jacques Philippe ◽  
...  

Abstract The Forkhead box A transcription factors are major regulators of glucose homeostasis. They show both distinct and redundant roles during pancreas development and in adult mouse β-cells. In vivo ablation studies have revealed critical implications of Foxa1 on glucagon biosynthesis and requirement of Foxa2 in α-cell terminal differentiation. In order to examine the respective role of these factors in mature α-cells, we used small interfering RNA (siRNA) directed against Foxa1 and Foxa2 in rat primary pancreatic α-cells and rodent α-cell lines leading to marked decreases in Foxa1 and Foxa2 mRNA levels and proteins. Both Foxa1 and Foxa2 control glucagon gene expression specifically through the G2 element. Although we found that Foxa2 controls the expression of the glucagon, MafB, Pou3f4, Pcsk2, Nkx2.2, Kir6.2, and Sur1 genes, Foxa1 only regulates glucagon gene expression. Interestingly, the Isl1 and Gipr genes were not controlled by either Foxa1 or Foxa2 alone but by their combination. Foxa1 and Foxa2 directly activate and bind the promoter region the Nkx2.2, Kir6.2 and Sur1, Gipr, Isl1, and Pou3f4 genes. We also demonstrated that glucagon secretion is affected by the combined effects of Foxa1 and Foxa2 but not by either one alone. Our results indicate that Foxa1 and Foxa2 control glucagon biosynthesis and secretion as well as α-cell differentiation with both common and unique target genes.


2020 ◽  
Vol 21 (8) ◽  
pp. 2800 ◽  
Author(s):  
Xi Wu ◽  
Yang Yang ◽  
Chaoyue Zhong ◽  
Yin Guo ◽  
Tengyu Wei ◽  
...  

Chromatin structure plays a pivotal role in maintaining the precise regulation of gene expression. Accessible chromatin regions act as the binding sites of transcription factors (TFs) and cis-elements. Therefore, information from these open regions will enhance our understanding of the relationship between TF binding, chromatin status and the regulation of gene expression. We employed an assay for transposase-accessible chromatin with high-throughput sequencing (ATAC-seq) and RNA-seq analyses in the gonads of protogynous hermaphroditic orange-spotted groupers during sex reversal to profile open chromatin regions and TF binding sites. We focused on several crucial TFs, including ZNF263, SPIB, and KLF9, and analyzed the networks of TF-target genes. We identified numerous transcripts exhibiting sex-preferred expression among their target genes, along with their associated open chromatin regions. We then investigated the expression patterns of sex-related genes as well as the mRNA localization of certain genes during sex reversal. We found a set of sex-related genes that—upon further study—might be identified as the sex-specific or cell-specific marker genes that trigger sex reversal. Moreover, we discovered the core genes (gnas, ccnb2, and cyp21a) of several pathways related to sex reversal that provide the guideposts for future study.


2011 ◽  
Vol 8 (65) ◽  
pp. 1673-1681 ◽  
Author(s):  
J. N. Milstein ◽  
J.-C. Meiners

DNA is traditionally seen as a linear sequence of instructions for cellular functions that are expressed through biochemical processes. Cellular DNA, however, is also organized as a complex hierarchical structure with a mosaic of mechanical features, and a growing body of evidence is now emerging to imply that these mechanical features are connected to genetic function. Mechanical tension, for instance, which must be felt by DNA within the heavily constrained and continually fluctuating cellular environment, can affect a number of regulatory processes implicating a role for biomechanics in gene expression complementary to that of biochemical regulation. In this article, we review evidence for such mechanical pathways of genetic regulation.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Vajiheh Safavi-Rizi ◽  
Marco Herde ◽  
Christine Stöhr

AbstractDue to climate change, economically important crop plants will encounter flooding periods causing hypoxic stress more frequently. This may lead to reduced yields and endanger food security. As roots are the first organ to be affected by hypoxia, the ability to sense and respond to hypoxic stress is crucial. At the molecular level, therefore, fine-tuning the regulation of gene expression in the root is essential for hypoxia tolerance. Using an RNA-Seq approach, we investigated transcriptome modulation in tomato roots of the cultivar ‘Moneymaker’, in response to short- (6 h) and long-term (48 h) hypoxia. Hypoxia duration appeared to have a significant impact on gene expression such that the roots of five weeks old tomato plants showed a distinct time-dependent transcriptome response. We observed expression changes in 267 and 1421 genes under short- and long-term hypoxia, respectively. Among these, 243 genes experienced changed expression at both time points. We identified tomato genes with a potential role in aerenchyma formation which facilitates oxygen transport and may act as an escape mechanism enabling hypoxia tolerance. Moreover, we identified differentially regulated genes related to carbon and amino acid metabolism and redox homeostasis. Of particular interest were the differentially regulated transcription factors, which act as master regulators of downstream target genes involved in responses to short and/or long-term hypoxia. Our data suggest a temporal metabolic and anatomic adjustment to hypoxia in tomato root which requires further investigation. We propose that the regulated genes identified in this study are good candidates for further studies regarding hypoxia tolerance in tomato or other crops.


2021 ◽  
Vol 12 ◽  
Author(s):  
Peng Yi ◽  
Xiongfeng Xu ◽  
Jiawei Yao ◽  
Bo Qiu

Abstract Objectives Transcriptional changes in cartilage can impact function by causing degradation such as that which occurs during the development of osteoarthritis (OA). Epigenetic regulation may be a key factor leading to transcriptional changes in OA. In this study, we performed a combined analysis of DNA methylation and gene expression microarray datasets and identified key transcription factors (TFs) central to the regulation of gene expression in OA. Methods A DNA methylation profile dataset (GSE63106) and a gene expression profiling dataset (GSE114007) were extracted from the Gene Expression Omnibus (GEO). We used ChAMP methylation analysis and the Limma package to identify differentially methylation genes (DMGs) and differentially expressed genes (DEGs) from normal and human knee cartilage samples in OA. Function enrichment analysis of DMGs was conducted using the DAVID database. A combined analysis of DEGs and DMGs was conducted to identify key TFs in OA. We then validated the mRNA expression of selected TFs in normal and OA cartilage by RT-qPCR. Primary chondrocytes were cultured and treated with the DNA methylation inhibitor 5-Aza-2-deoxycytidine (5-Aza) for functional validation. Results We identified 2,170 differential methylation sites (DMS) containing 1005 genes and 1986 DEGs between normal human and OA cartilage. Functional analysis of DMGs revealed that focal adhesion, extracellular matrix (ECM)-receptor interactions, the PI3K-Akt signaling pathway, and the FoxO signaling pathway were involved in OA. Integrated analysis showed a subset of 17 TFs. Four TFs (ELF3, SOX11, RARA, and FOXD2) were validated. RT-qPCR results showed the mRNA expression of SOX11, RARA, and FOXD2 were consistent with the results from the mRNA expression data. However, the expression of ELF3 could not be validated. Upon 5-Aza-2′-deoxycytidine (5-Aza) treatment, the mRNA levels of ELF3 and SOX11 were down-regulated, whilst RARA was up-regulated, and FOXD2 showed no significant change in expression level. Conclusions the effect of DNA methylation on the transcriptional regulation is related to the distribution of methylated sites across the genome. Epigenetic studies on the positions of DMS in transcriptional units can inform a better understanding of the function of DNA methylation and its transcription regulation.


2019 ◽  
Vol 24 (39) ◽  
pp. 4659-4667 ◽  
Author(s):  
Mona Fani ◽  
Milad Zandi ◽  
Majid Rezayi ◽  
Nastaran Khodadad ◽  
Hadis Langari ◽  
...  

MicroRNAs (miRNAs) are non-coding RNAs with 19 to 24 nucleotides which are evolutionally conserved. MicroRNAs play a regulatory role in many cellular functions such as immune mechanisms, apoptosis, and tumorigenesis. The main function of miRNAs is the post-transcriptional regulation of gene expression via mRNA degradation or inhibition of translation. In fact, many of them act as an oncogene or tumor suppressor. These molecular structures participate in many physiological and pathological processes of the cell. The virus can also produce them for developing its pathogenic processes. It was initially thought that viruses without nuclear replication cycle such as Poxviridae and RNA viruses can not code miRNA, but recently, it has been proven that RNA viruses can also produce miRNA. The aim of this articles is to describe viral miRNAs biogenesis and their effects on cellular and viral genes.


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