Mouse Polycomb M33 is required for splenic vascular and adrenal gland formation through regulating Ad4BP/SF1 expression

Abstract Mice with disrupted mammalian PcG (Polycomb group) genes commonly show skeletal transformation of anterior-posterior identities. Disruption of the murine M33 gene, a PcG member, displayed posterior transformation of the vertebral columns and sternal ribs. In addition, failure of T-cell expansion and hypoplasia and sex-reversal of the gonads, have been observed. In the present study, we identified defects in the splenic and adrenal formation of M33–knock-out (KO) mice on a C57BL/6 genetic background. The spleen in these animals was smaller than in the wild-type mice and was spotted red because of nonuniform distribution of blood cells. Histologic examination revealed disorganization of the vascular endothelium and its surrounding structures, and immunohistochemistry demonstrated disturbances in vascular formation and colonization of immature hematopoietic cells. These splenic phenotypes observed in the M33-KO mice were quite similar to those seen in Ad4BP/SF1 (Nr5a1) knock-outs. Moreover, the adrenal glands of M33-KO and Ad4BP/SF1 heterozygous KO mice were smaller than those of the wild-type mice. Western blot, immunohistochemistry, and reverse transcriptase–polymerase chain reaction (RT-PCR) analyses of the M33 knock-outs all indicated significantly low expression of adrenal 4 binding protein/steroidogenic factor-1 (Ad4BP/SF-1), indicating that M33 is an essential upstream regulator of Ad4BP/SF1. In agreement with these observations, chromatin immunoprecipitation assays with adrenocortical Y-1 cells revealed direct binding of the M33-containing PcG to the Ad4BP/SF1 gene locus.

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E(z): a polycomb group gene or a trithorax group gene?

Development ◽

10.1242/dev.122.7.2189 ◽

1996 ◽

Vol 122 (7) ◽

pp. 2189-2197 ◽

Cited By ~ 6

Author(s):

D. LaJeunesse ◽

A. Shearn

Keyword(s):

Polycomb Group ◽

Bithorax Complex ◽

Trithorax Group ◽

Polycomb Group Genes ◽

Enhancer Of Zeste ◽

Selector Genes ◽

Homeotic Selector Genes ◽

Polycomb Group Gene ◽

Anterior Posterior ◽

Homeotic Selector

The products of the Polycomb group of genes are cooperatively involved in repressing expression of homeotic selector genes outside of their appropriate anterior/posterior boundaries. Loss of maternal and/or zygotic function of Polycomb group genes results in the ectopic expression of both Antennapedia Complex and Bithorax Complex genes. The products of the trithorax group of genes are cooperatively involved in maintaining active expression of homeotic selector genes within their appropriate anterior/posterior boundaries. Loss of maternal and/or zygotic function of trithorax group genes results in reduced expression of both Antennapedia Complex and Bithorax Complex genes. Although Enhancer of zeste has been classified as a member of the Polycomb group, in this paper we show that Enhancer of zeste can also be classified as a member of the trithorax group. The requirement for Enhancer of zeste activity as either a trithorax group or Polycomb group gene depends on the homeotic selector gene locus as well as on spatial and temporal cues.

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Embryonic geometry underlies phenotypic variation in decanalized conditions

10.1101/579623 ◽

2019 ◽

Author(s):

A. Huang ◽

T. E. Saunders

Keyword(s):

Phenotypic Variation ◽

Regulatory Network ◽

Physical Space ◽

Model Organisms ◽

Wild Type ◽

Environmental Perturbations ◽

Key Factor ◽

In The Wild ◽

Gene Regulatory ◽

Anterior Posterior

AbstractDuring development, many mutations cause increased variation in phenotypic outcomes, a phenomenon termed decanalization. Such variations can often be attributed to genetic and environmental perturbations. However, phenotypic discordance remains even in isogenic model organisms raised in homogeneous environments. To understand the mechanisms underlying phenotypic variation, we used as a model the highly precise anterior-posterior (AP) patterning of the early Drosophila embryo. We decanalized the system by depleting the maternal bcd product and found that in contrast to the highly scaled patterning in the wild-type, the segmentation gene boundaries shift away from the scaled positions according to the total embryonic length. Embryonic geometry is hence a key factor predetermining patterning outcomes in such decanalized conditions. Embryonic geometry was also found to predict individual patterning outcomes under bcd overexpression, another decanalizing condition. Further analysis of the gene regulatory network acting downstream of the morphogen identified vulnerable points in the networks due to limitations in the available physical space.

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Caenorhabditis elegans triple null mutant lacking UDP-N-acetyl-D-glucosamine:α-3-D-mannoside β1,2-N-acetylglucosaminyltransferase I

Biochemical Journal ◽

10.1042/bj20040793 ◽

2004 ◽

Vol 382 (3) ◽

pp. 995-1001 ◽

Cited By ~ 46

Author(s):

Shaoxian ZHU ◽

Andrew HANNEMAN ◽

Vernon N. REINHOLD ◽

Andrew M. SPENCE ◽

Harry SCHACHTER

Keyword(s):

Caenorhabditis Elegans ◽

Chromosome Number ◽

Null Mutant ◽

Wild Type ◽

Knock Out ◽

C Elegans ◽

In The Wild ◽

Wild Type Worm ◽

Type C ◽

Nematode Worm

We have previously reported, from the nematode worm Caenor-habditis elegans, three genes (gly-12, gly-13 and gly-14) encoding enzymically active UDP-N-acetyl-D-glucosamine:α-3-D-mannoside β1,2-N-acetylglucosaminyltransferase I (GnT I), an enzyme essential for hybrid, paucimannose and complex N-glycan synthesis. We now describe a worm with null mutations in all three GnT I genes, gly-14 (III);gly-12 gly-13 (X) (III and X refer to the chromosome number). The triple-knock-out (TKO) worms have a normal phenotype, although they do not express GnT I activity and do not synthesize 31 paucimannose, complex and fucosylated oligomannose N-glycans present in the wild-type worm. The TKO worm has increased amounts of non-fucosylated oligomannose N-glycan structures, a finding consistent with the site of GnT I action. Five fucosylated oligomannose N-glycan structures were observed in TKO, but not wild-type, worms, indicating the presence of unusual GnT I-independent fucosyltransferases. It is concluded that wild-type C. elegans makes a large number of GnT I-dependent N-glycans that are not essential for normal worm development under laboratory conditions. The TKO worm may be more susceptible to mutations in other genes, thereby providing an approach for the identification of genes that interact with GnT I.

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Construction of afurnull mutant and RNA-sequencing provide deeper global understanding of theAliivibrio salmonicidaFur regulon

PeerJ ◽

10.7717/peerj.3461 ◽

2017 ◽

Vol 5 ◽

pp. e3461 ◽

Cited By ~ 3

Author(s):

Sunniva Katharina Thode ◽

Cecilie Bækkedal ◽

Jenny Johansson Söderberg ◽

Erik Hjerde ◽

Hilde Hansen ◽

...

Keyword(s):

Rna Sequencing ◽

Iron Homeostasis ◽

Target Genes ◽

Iron Acquisition ◽

Null Mutant ◽

Wild Type ◽

Knock Out ◽

In The Wild ◽

Global Understanding ◽

Main Regulator

BackgroundThe ferric uptake regulator (Fur) is a transcription factor and the main regulator of iron acquisition in prokaryotes. When bound to ferric iron, Fur recognizes its DNA binding site and generally executes its function by repressing transcription of its target genes. Due to its importance in virulence, the Fur regulon is well studied for several model bacteria. In our previous work, we used computational predictions and microarray to gain insights into Fur-regulation inAliivibrio salmonicida, and have identified a number of genes and operons that appear to be under direct control of Fur. To provide a more accurate and deeper global understanding of the biological role of Fur we have now generated anA. salmonicida furknock-out strain and used RNA-sequencing to compare gene expression between the wild-type andfurnull mutant strains.ResultsAnA. salmonicida furnull mutant strain was constructed. Biological assays demonstrate that deletion offurresults in loss of fitness, with reduced growth rates, and reduced abilities to withstand low-iron conditions, and oxidative stress. When comparing expression levels in the wild-type and thefurnull mutant we retrieved 296 differentially expressed genes distributed among 18 of 21 functional classes of genes. A gene cluster encoding biosynthesis of the siderophore bisucaberin represented the highest up-regulated genes in thefurnull mutant. Other highly up-regulated genes all encode proteins important for iron acquisition. Potential targets for the RyhB sRNA was predicted from the list of down-regulated genes, and significant complementarities were found between RyhB and mRNAs of thefur,sodB,cysNand VSAL_I0422 genes. Other sRNAs with potential functions in iron homeostasis were identified.ConclusionThe present work provides by far the most comprehensive and deepest understanding of the Fur regulon inA. salmonicidato date. Our data also contribute to a better understanding of how Fur plays a key role in iron homeostasis in bacteria in general, and help to show how Fur orchestrates iron uptake when iron levels are extremely low.

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Contribution of PPARγ in modulation of acrolein-induced inflammatory signaling in gp91phox knock-out mice

Biochemistry and Cell Biology ◽

10.1139/bcb-2016-0198 ◽

2017 ◽

Vol 95 (4) ◽

pp. 482-490 ◽

Cited By ~ 3

Author(s):

Zivar Yousefipour ◽

Neha Chug ◽

Katarzyna Marek ◽

Alicia Nesbary ◽

Joseph Mathew ◽

...

Keyword(s):

Oxidative Stress ◽

Body Mass ◽

Total Antioxidant Status ◽

Peroxisome Proliferator ◽

Wild Type ◽

Peroxisome Proliferator Activated Receptor ◽

Knock Out ◽

Total Antioxidant ◽

In The Wild ◽

Knock Out Mice

Oxidative stress and inflammation are major contributors to acrolein toxicity. Peroxisome proliferator activated receptor gamma (PPARγ) has antioxidant and anti-inflammatory effects. We investigated the contribution of PPARγ ligand GW1929 to the attenuation of oxidative stress in acrolein-induced insult. Male gp91phox knock-out (KO) mice were treated with acrolein (0.5 mg·(kg body mass)–1 by intraperitoneal injection for 7 days) with or without GW1929 (GW; 0.5 mg·(kg body mass)–1·day–1, orally, for 10 days). The livers were processed for further analyses. Acrolein significantly increased 8-isoprostane and reduced PPARγ activity (P < 0.05) in the wild type (WT) and KO mice. GW1929 reduced 8-isoprostane (by 32% and 40% in WT and KO mice, respectively) and increased PPARγ activity (by 81% and 92% in WT and KO, respectively). Chemokine activity was increased (by 63%) in acrolein-treated WT mice, and was reduced by GW1929 (by 65%). KO mice exhibited higher xanthine oxidase (XO). Acrolein increased XO and COX in WT mice and XO in KO mice. GW1929 significantly reduced COX in WT and KO mice and reduced XO in KO mice. Acrolein significantly reduced the total antioxidant status in WT and KO mice (P < 0.05), which was improved by GW1929 (by 75% and 74%). The levels of NF-κB were higher in acrolein-treated WT mice. GW1929 reduced NF-κB levels (by 51%) in KO mice. Acrolein increased CD36 in KO mice (by 43%), which was blunted with GW1929. Data confirms that the generation of free radicals by acrolein is mainly through NAD(P)H, but other oxygenates play a role too. GW1929 may alleviate the toxicity of acrolein by attenuating NF-κB, COX, and CD36.

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Regulation of ciaXRH Operon Expression and Identification of the CiaR Regulon in Streptococcus mutans

Journal of Bacteriology ◽

10.1128/jb.00556-10 ◽

2010 ◽

Vol 192 (18) ◽

pp. 4669-4679 ◽

Cited By ~ 12

Author(s):

Chenggang Wu ◽

Eduardo A. Ayala ◽

Jennifer S. Downey ◽

Justin Merritt ◽

Steven D. Goodman ◽

...

Keyword(s):

Streptococcus Mutans ◽

Fold Increase ◽

Null Mutant ◽

Wild Type ◽

Double Deletion ◽

Transcriptional Alterations ◽

In The Wild ◽

Direct Binding ◽

Operon Expression

ABSTRACT The ciaRH operon in Streptococcus mutans contains 3 contiguous genes, ciaXRH. Unlike the CiaRH system in other streptococci, only the ciaH-null mutant displays defective phenotypes, while the ciaR-null mutant behaves like the wild type. The objective of this study was to determine the mechanism of this unusual property. We demonstrate that the ciaH mutation caused a >20-fold increase in ciaR transcript synthesis. A ciaRH double deletion reversed the ciaH phenotype, suggesting that overexpressed ciaR might be responsible for the observed ciaH phenotypes. When ciaR was forced to be overexpressed by a transcriptional fusion to the ldh promoter in the wild-type background, the same ciaH phenotypes were restored, confirming the involvement of overexpressed ciaR in the ciaH phenotypes. The ciaH mutation and ciaR overexpression also caused transcriptional alterations in 100 genes, with 15 genes upregulated >5-fold. Bioinformatics analysis identified a putative CiaR regulon consisting of 8 genes/operons, including the ciaXRH operon itself, all of which were upregulated. In vitro footprinting on 4 of the 8 promoters revealed a protected region of 26 to 28 bp encompassing two direct repeats, NTTAAG-n5-WTTAAG, 10 bp upstream of the −10 region, indicating direct binding of the CiaR protein to these promoters. Taken together, we conclude that overexpressed CiaR, as a result of either ciaH deletion or forced expression from a constitutive promoter, is a mediator in the CiaH-regulated phenotypes.

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Freeze-substituted fungal cells of Nectria haematococca: A comparison of the macroconidial walls of the adhesion-competent wild type with an adhesion-reduced mutant

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100160996 ◽

1990 ◽

Vol 48 (3) ◽

pp. 688-689

Author(s):

Thecan Caesar-Ton That ◽

Lynn Epstein

Keyword(s):

Freeze Substitution ◽

Uranyl Acetate ◽

Wild Type ◽

Nectria Haematococca ◽

Fruit Extract ◽

Dialysis Tubing ◽

Tube Emergence ◽

Contrast Microscopy ◽

In The Wild ◽

Freeze Damage

Nectria haematococca mating population I (anamorph, Fusarium solani) macroconidia attach to its host (squash) and non-host surfaces prior to germ tube emergence. The macroconidia become adhesive after a brief period of protein synthesis. Recently, Hickman et al. (1989) isolated N. haematococca adhesion-reduced mutants. Using freeze substitution, we compared the development of the macroconidial wall in the wild type in comparison to one of the mutants, LEI.Macroconidia were harvested at 1C, washed by centrifugation, resuspended in a dilute zucchini fruit extract and incubated from 0 - 5 h. During the incubation period, wild type macroconidia attached to uncoated dialysis tubing. Mutant macroconidia did not attach and were collected on poly-L-lysine coated dialysis tubing just prior to freezing. Conidia on the tubing were frozen in liquid propane at 191 - 193C, substituted in acetone with 2% OsO4 and 0.05% uranyl acetate, washed with acetone, and flat-embedded in Epon-Araldite. Using phase contrast microscopy at 1000X, cells without freeze damage were selected, remounted, sectioned and post-stained sequentially with 1% Ba(MnO4)2 2% uranyl acetate and Reynold’s lead citrate. At least 30 cells/treatment were examined.

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