ALTERED STEROID INDUCED PUFFING BY CHROMATIN BOUND ALUMINUM IN A POLYTENE CHROMOSOME OF THE BLACKFLY SIMULIUM VITTATUM

1982 ◽  
Vol 24 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Catherine L. Sanderson ◽  
Donald R. Crapper McLachlan ◽  
Umberto De Boni
Keyword(s):  
Gene Expression ◽  
Salivary Gland ◽  
Polytene Chromosomes ◽  
Cell Types ◽  
Toxic Action ◽  
Nuclear Chromatin ◽  
Experimental Animals ◽  
Simulium Vittatum ◽  
Salivary Gland Cells

The neurotoxic element aluminum accumulates selectively upon nuclear chromatin of several cell types, including neurons and glial cells of experimental animals and man. However, no mechanism of toxic action has been identified. Histometric analyses of the puffing patterns induced by ecdysterone in polytene chromosomes in the dipteran, Simulium vittatum (Zetterstedt) showed that chromosomes of salivary gland cells exposed to aluminum in vitro exhibit significant alterations in their response to ecdysterone. Specifically, chromatin bound aluminum completely inhibits (p < 0.05) puffing at seven out of nine sites normally puffed by ecdysterone and partially inhibits (p < 0.05) puffing at one site. Aluminum induces a partial puff (p < 0.05) at one site previously inhibited when both aluminum and ecdysterone were present. These findings suggest that one mode of toxic action of chromatin bound aluminum may be related to changes in gene expression.

scholarly journals Valproic Acid Increases the Hepatic Differentiation Potential of Salivary Gland Cells

Acta Naturae ◽  
2015 ◽  
Vol 7 (4) ◽  
pp. 80-92 ◽  
Author(s):  
O. S. Petrakova ◽  
V. V. Ashapkin ◽  
V. Yu. Shtratnikova ◽  
L. I. Kutueva ◽  
E. A. Vorotelyak ◽  
...  
Keyword(s):  
Gene Expression ◽  
Valproic Acid ◽  
Salivary Gland ◽  
Cell Types ◽  
Submandibular Salivary Gland ◽  
Hepatic Differentiation ◽  
Differentiation Potential ◽  
Expression Levels ◽  
Gland Cells ◽  
Salivary Gland Cells

The studies of cell plasticity and differentiation abilities are important problems in modern cellular biology. The use of histone deacetylase inhibitor - valproic acid is a promising approach to increasing the differentiation efficiency of various cell types. In this paper we investigate the ability of mouse submandibular salivary gland cells to differentiate into the hepatic direction and the effect of valproic acid on the efficiency of this differentiation. It was shown that the gene expression levels of hepatocyte markers (Aat, Afp, G6p, Pepck, Tat, Cyp3a13) and liver-enriched transcription factors (Hnf-3, Hnf-3, Hnf-4, Hnf-6) were increased after differentiation in salivary gland cells. Valproic acid increases the specificity of hepatic differentiation, reducing the expression levels of the ductal (Krt19, Hhex1, Cyp7a1) and acinar (Ptf1a) markers. After valproic acid exposure, the efficiency of hepatic differentiation also increases, as evidenced by the increase in the gene expression level of Alb and Tdo, and increase in urea production by differentiated cells. No change was found in DNA methylation of the promoter regions of the genes; however, valproic acid treatment and subsequent hepatic differentiation largely affected the histone H3 methylation of liver-enriched genes. Thus, mouse submandibular salivary gland cells are capable of effective differentiation in the hepatic direction. Valproic acid increases the specificity and efficiency of the hepatic differentiation of these cells.

scholarly journals Enhancing droplet-based single-nucleus RNA-seq resolution using the semi-supervised machine learning classifier DIEM

2019 ◽  
Author(s):  
Marcus Alvarez ◽  
Elior Rahmani ◽  
Brandon Jew ◽  
Kristina M. Garske ◽  
Zong Miao ◽  
...  
Keyword(s):  
Gene Expression ◽  
Single Cell ◽  
Cell Types ◽  
Supervised Machine Learning ◽  
Data Sets ◽  
Rna Seq ◽  
Novel Approach ◽  
Single Nucleus ◽  
Downstream Analysis

AbstractSingle-nucleus RNA sequencing (snRNA-seq) measures gene expression in individual nuclei instead of cells, allowing for unbiased cell type characterization in solid tissues. Contrary to single-cell RNA seq (scRNA-seq), we observe that snRNA-seq is commonly subject to contamination by high amounts of extranuclear background RNA, which can lead to identification of spurious cell types in downstream clustering analyses if overlooked. We present a novel approach to remove debris-contaminated droplets in snRNA-seq experiments, called Debris Identification using Expectation Maximization (DIEM). Our likelihood-based approach models the gene expression distribution of debris and cell types, which are estimated using EM. We evaluated DIEM using three snRNA-seq data sets: 1) human differentiating preadipocytes in vitro, 2) fresh mouse brain tissue, and 3) human frozen adipose tissue (AT) from six individuals. All three data sets showed various degrees of extranuclear RNA contamination. We observed that existing methods fail to account for contaminated droplets and led to spurious cell types. When compared to filtering using these state of the art methods, DIEM better removed droplets containing high levels of extranuclear RNA and led to higher quality clusters. Although DIEM was designed for snRNA-seq data, we also successfully applied DIEM to single-cell data. To conclude, our novel method DIEM removes debris-contaminated droplets from single-cell-based data fast and effectively, leading to cleaner downstream analysis. Our code is freely available for use at https://github.com/marcalva/diem.

scholarly journals H3K9 Promotes Under-Replication of Pericentromeric Heterochromatin in Drosophila Salivary Gland Polytene Chromosomes

Genes ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 93 ◽  
Author(s):  
Robin Armstrong ◽  
Taylor Penke ◽  
Samuel Chao ◽  
Gabrielle Gentile ◽  
Brian Strahl ◽  
...  
Keyword(s):  
Salivary Gland ◽  
Dna Replication ◽  
Polytene Chromosomes ◽  
Cell Types ◽  
Gene Replacement ◽  
Pericentric Heterochromatin ◽  
Replication Initiation ◽  
H3k9 Methylation ◽  
Diploid Cells ◽  
And Function

Chromatin structure and its organization contributes to the proper regulation and timing of DNA replication. Yet, the precise mechanism by which chromatin contributes to DNA replication remains incompletely understood. This is particularly true for cell types that rely on polyploidization as a developmental strategy for growth and high biosynthetic capacity. During Drosophila larval development, cells of the salivary gland undergo endoreplication, repetitive rounds of DNA synthesis without intervening cell division, resulting in ploidy values of ~1350C. S phase of these endocycles displays a reproducible pattern of early and late replicating regions of the genome resulting from the activity of the same replication initiation factors that are used in diploid cells. However, unlike diploid cells, the latest replicating regions of polyploid salivary gland genomes, composed primarily of pericentric heterochromatic enriched in H3K9 methylation, are not replicated each endocycle, resulting in under-replicated domains with reduced ploidy. Here, we employ a histone gene replacement strategy in Drosophila to demonstrate that mutation of a histone residue important for heterochromatin organization and function (H3K9) but not mutation of a histone residue important for euchromatin function (H4K16), disrupts proper endoreplication in Drosophila salivary gland polyploid genomes thereby leading to DNA copy gain in pericentric heterochromatin. These findings reveal that H3K9 is necessary for normal levels of under-replication of pericentric heterochromatin and suggest that under-replication at pericentric heterochromatin is mediated through H3K9 methylation.

P0658MATRIX AND FLOW MODULATE GENE EXPRESSION IN A 3D VASCULARISED TUBULE MODEL

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Julie Williams ◽  
Sanlin Robinson ◽  
Babak Alaei ◽  
Kimberly Homan ◽  
Maryam Clausen ◽  
...  
Keyword(s):  
Gene Expression ◽  
Extracellular Matrix ◽  
Impact Analysis ◽  
Cell Types ◽  
Drug Uptake ◽  
Shear Stresses ◽  
The Matrix ◽  
And Function

Abstract Background and Aims Questions abound regarding the translation of in vitro 2D cell culture systems to the human setting. This is especially true of the kidney in which there is a complex hierarchical structure and a multitude of cell types. While it is well accepted that extracellular matrix plays a large part in directing cellular physiology emerging research has highlighted the importance of shear stresses and flow rates too. To fully recapitulate the normal gene expression and function of a particular renal cell type how important is it to completely reconstitute their in vivo surroundings? Method To answer this question, we have cultured proximal tubular (PT) epithelial cells in a 3-dimensional channel embedded within an engineered extracellular matrix (ECM) under physiological flow that is colocalised with an adjacent channel lined with renal microvascular endothelial cells that mimic a peritubular capillary. Modifications to the system were made to allow up to 12 chips to be run in parallel in an easily handleable form. After a period of maturation under continuous flow, both cell types were harvested for RNAseq analyses. RNA expression data was compared with cells cultured under static 2-dimensional conditions on plastic or the engineered ECM. Additionally, the perfusion of glucose through this 3D vascularised PT model has been investigated in the presence and absence of known diabetes modulating agents. Results PCA of RNAseq data showed that a) static non-coated, b) static matrix-coated and c) flow matrix-coated conditions separated into 3 distinct groups, while cell co-culture had less impact. Analysis of transcriptomic signatures showed that many genes were modulated by the matrix with additional genes influenced under flow conditions. Several of these genes, classified as transporters, are of particular importance when using this model to assess drug uptake and safety implications. Co-culture regulated some interesting genes, but fewer than anticipated. Preliminary experiments are underway to monitor glucose uptake and transport between tubules under different conditions. Conclusion We have developed a medium throughput system in which matrix and flow modulate gene expression. This system can be used to study the physiology of molecular cross-talk between cells. Ongoing analysis will further consider relevance to human physiology.

scholarly journals Anti-Ro and anti-La autoantibodies induce TNF-α production by human salivary gland cells: an in vitro study

Reumatismo ◽  
2011 ◽  
Vol 59 (3) ◽  
Author(s):  
M. Sisto ◽  
S. Lisi ◽  
M. D'Amore ◽  
V. Mitolo ◽  
P. Scagliusi
Keyword(s):  
Salivary Gland ◽  
In Vitro Study ◽  
Vitro Study ◽  
Human Salivary Gland ◽  
Gland Cells ◽  
Salivary Gland Cells ◽  
Tnf Α

scholarly journals Glucocorticoid receptor action in metabolic and neuronal function

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 1208 ◽  
Author(s):  
Michael J. Garabedian ◽  
Charles A. Harris ◽  
Freddy Jeanneteau
Keyword(s):  
Gene Expression ◽  
Glucocorticoid Receptor ◽  
Metabolic Diseases ◽  
Cell Types ◽  
Health And Disease ◽  
And Behavior ◽  
External Signals ◽  
The Brain

Glucocorticoids via the glucocorticoid receptor (GR) have effects on a variety of cell types, eliciting important physiological responses via changes in gene expression and signaling. Although decades of research have illuminated the mechanism of how this important steroid receptor controls gene expression using in vitro and cell culture–based approaches, how GR responds to changes in external signals in vivo under normal and pathological conditions remains elusive. The goal of this review is to highlight recent work on GR action in fat cells and liver to affect metabolism in vivo and the role GR ligands and receptor phosphorylation play in calibrating signaling outputs by GR in the brain in health and disease. We also suggest that both the brain and fat tissue communicate to affect physiology and behavior and that understanding this “brain-fat axis” will enable a more complete understanding of metabolic diseases and inform new ways to target them.

The Balbiani ring and the polytene chromosomes of Drosophila bicornuta

Genome ◽  
1992 ◽  
Vol 35 (1) ◽  
pp. 64-67 ◽  
Author(s):  
P. Mavragani-Tsipidou ◽  
Z. G. Scouras ◽  
A. Natsiou-Voziki
Keyword(s):  
Salivary Gland ◽  
Larval Development ◽  
Banding Pattern ◽  
Polytene Chromosomes ◽  
Balbiani Ring

A study of the BR1 and of the most prominent puffs during larval development and after in vitro ecdysterone treatment, as well as of the banding pattern and inverted tandem chromosomal duplications of the salivary gland chromosomes of Drosophila bicornuta, is presented in this report. These data are compared and discussed with those of D. auraria and D. serrata, two other montium species.Key words: Drosophila, Balbiani ring, duplications, ecdysterone.

Novel Disulfide-Containing Poly(β-amino ester)-Functionalised Magnetic Nanoparticles for Efficient Gene Delivery

2016 ◽  
Vol 69 (3) ◽  
pp. 349 ◽  
Author(s):  
Yucheng Liu ◽  
Shufeng Li ◽  
Liandong Feng ◽  
Hao Yu ◽  
Xiaoliang Qi ◽  
...  
Keyword(s):  
Gene Expression ◽  
Magnetic Nanoparticles ◽  
Disulfide Bonds ◽  
Transfection Efficiency ◽  
A549 Cells ◽  
Weight Ratio ◽  
Cell Types ◽  
Amino Ester ◽  
Gene Complexes

Poly(β-amino ester)s (PBAEs) have been proved to effectively transfer DNA to various cell types. However, PBAEs with high molecular weights also show considerable toxicities, partly resulting from inadequate degradation of their polyester backbone. In this study, we created novel poly(β-amino ester)s (SF-1, 2, 3, and 4; notation SFs refers to all the four polymers) which were characterised by the cleavable disulfide bonds. Moreover, a new technique, termed magnetofection that uses magnetic nanoparticles to enhance gene expression, has recently been well developed. The negatively charged magnetic nanoparticles (MNPs) with good biocompatibility in vitro were prepared here to subsequently combine with SFs and DNA via electrostatic interaction, leading to the formation of the magnetic gene complexes MNP/SFs/DNA. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays and transfection experiments were performed in A549 cells to investigate all the resulting complexes. Studies indicated that the synthesised PBAEs exhibited good biodegradation and regulated release of DNA as a result of the reductive cleavage of the disulfide bonds, giving higher transfection efficiency along with much lower cytotoxicity compared with commercially available transfection agent polyethylenimine (Mw 25 kDa). Furthermore, when MNP was involved at a MNP/DNA weight ratio of 0.5, the magnetic gene complexes MNP/SFs/DNA showed enhanced levels of gene expression while maintaining low cytotoxicity.

scholarly journals Drosophila Ada2b Is Required for Viability and Normal Histone H3 Acetylation

2004 ◽  
Vol 24 (18) ◽  
pp. 8080-8089 ◽  
Author(s):  
Dai Qi ◽  
Jan Larsson ◽  
Mattias Mannervik
Keyword(s):  
Gene Expression ◽  
Transcriptional Activation ◽  
Protein Complexes ◽  
P53 Protein ◽  
Polytene Chromosomes ◽  
Histone H3 ◽  
Saga Complex ◽  
Histone H3 Acetylation ◽  
H3 Acetylation

ABSTRACT Regulation of chromatin through histone acetylation is an important step in gene expression. The Gcn5 histone acetyltransferase is part of protein complexes, e.g., the SAGA complex, that interact with transcriptional activators, targeting the enzyme to specific promoters and assisting in recruitment of the basal RNA polymerase transcription machinery. The Ada2 protein directly binds to Gcn5 and stimulates its catalytic activity. Drosophila contains two Ada2 proteins, Drosophila Ada2a (dAda2a) and dAda2b. We have generated flies that lack dAda2b, which is part of a Drosophila SAGA-like complex. dAda2b is required for viability in Drosophila, and its deletion causes a reduction in histone H3 acetylation. A global hypoacetylation of chromatin was detected on polytene chromosomes in dAda2b mutants. This indicates that the dGcn5-dAda2b complex could have functions in addition to assisting in transcriptional activation through gene-specific acetylation. Although the Drosophila p53 protein was previously shown to interact with the SAGA-like complex in vitro, we find that p53 induction of reaper gene expression occurs normally in dAda2b mutants. Moreover, dAda2b mutant animals show excessive p53-dependent apoptosis in response to gamma radiation. Based on this result, we speculate that dAda2b may be necessary for efficient DNA repair or generation of a DNA damage signal. This could be an evolutionarily conserved function, since a yeast ada2 mutant is also sensitive to a genotoxic agent.

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