scholarly journals ANALYSIS OF CHD-7 DEFECTIVE DAUER NEMATODES IMPLICATES COLLAGEN MISREGULATION IN CHARGE SYNDROME FEATURES

2021 ◽  
Author(s):  
Diego Martín Jofré ◽  
Dane Kristian Hoffman ◽  
Ailen S. Cervino ◽  
McKenzie Grundy ◽  
Sijung Yun ◽  
...  
Keyword(s):  
Charge Syndrome ◽  
Mrna Levels ◽  
Craniofacial Malformations ◽  
Developmental Defects ◽  
The Public ◽  
Over Expression ◽  
C Elegans ◽  
Genetic Epistasis ◽  
Collagen Genes ◽  
Craniofacial Defects

ABSTRACTCHARGE syndrome is a complex developmental disorder caused by mutations in the chromodomain helicase DNA-binding protein7 (CHD7) and characterized by retarded growth and malformations in the heart and nervous system. However, despite the public health relevance of this disorder, relevant targets of CHD7 that relate to disease pathology are still poorly understood. Here we report thatchd-7, the nematode ortholog of CHD7, is required for dauer morphogenesis, lifespan determination, and stress response. Genetic epistasis placedchd-7in the TGF-β pathway. Consistent with our discoveries, we foundchd-7to be allelic toscd-3, a previously identified dauer suppressor from the TGF-β pathway. Interestingly, DAF-12 transcriptionally upregulatedchd-7, which is necessary to repressdaf-9for execution of the dauer program. Transcriptomic analysis comparingchd-7–defective and normal dauers showed enrichment of collagen genes, consistent with a conserved role for the TGF-β pathway in expression of the extracellular matrix. To validate a conserved function forchd-7in vertebrates, we usedXenopus laevisembryos, an established model to study craniofacial development. Morpholino mediated knockdown of Chd7 led to embryonic lethality, a reduction incol2a1mRNA levels and craniofacial defects in tadpoles. Both lethality and malformations were partially rescued in Chd7-depleted embryos by over-expression ofcol2a1. We suggest that pathogenic features of CHARGE syndrome caused by Chd7 mutations, such as craniofacial malformations, result from the reduction of collagen levels. These studies establishC. elegansas an amenable animal model to study the etiology of the developmental defects associated with pathogenic Chd7.

Stage-specific patterns of collagen gene expression during development of Caenorhabditis elegans

1985 ◽  
Vol 5 (2) ◽  
pp. 363-372
Author(s):  
G N Cox ◽  
D Hirsh
Keyword(s):  
Caenorhabditis Elegans ◽  
Protein Composition ◽  
Large Family ◽  
Major Protein ◽  
Mrna Levels ◽  
Mrna Accumulation ◽  
C Elegans ◽  
Collagen Protein ◽  
Protein Components ◽  
Collagen Genes

Collagens are the major protein components of the Caenorhabditis elegans cuticle and are encoded by a large family of 40 to 150 closely related but nonidentical genes. We have determined temporal patterns of mRNA accumulation for a large number of collagen genes by screening recombinant phages and plasmids containing cloned collagen genes under high stringency conditions with 32P-labeled cDNA preparations specific for eggs or three postembryonic molts. We find that collagen mRNA levels are regulated both temporally and quantitatively during C. elegans development. Most genes studied exhibit one of four patterns of mRNA accumulation which correlate with changes in cuticle morphology and collagen protein composition during development. Our results suggest that, in general, there is a progressive activation of new collagen genes during normal development.

scholarly journals Developmental fidelity imposed by the RGL-1 “Balanced Switch” mediating opposing signals

2018 ◽  
Author(s):  
Hanna Shin ◽  
Christian Braendle ◽  
Kimberly B. Monahan ◽  
Rebecca E.W. Kaplan ◽  
Tanya P. Zand ◽  
...  
Keyword(s):  
Cell Fates ◽  
Developmental Defects ◽  
C Elegans ◽  
Canonical Map ◽  
Environmental Perturbations ◽  
Map Kinase Cascade ◽  
Vulval Precursor Cells ◽  
Genetic Epistasis ◽  
Kinase Cascade ◽  
Dsl Ligands

AbstractThe six C. elegans vulval precursor cells (VPCs) are induced to form the 30-30-20-Γ-20-3° pattern of cell fates with high fidelity. In response to EGF signal, the LET-60/Ras-LIN-45/Raf-MEK-2/MEK-MPK-1/ERK canonical MAP kinase cascade is necessary to induce 1° fate and synthesis of DSL ligands. In turn, LIN-12/Notch signal is necessary to induce neighboring cells to become 2°. We previously showed that, in response to lower dose of EGF signal, the modulatory LET-60/Ras-RGL-1/RalGEF-RAL-1/Ral signal promotes 2° fate in support of LIN-12. In this study we identify two key differences between RGL-1 and RAL-1 functions. First, deletion of RGL-1 confers no overt developmental defects, while previous studies showed RAL-1 to be essential for viability and fertility. From this observation we hypothesize that the developmentally essential functions of RAL-1 are independent of upstream activation. Second, RGL-1 plays opposing and genetically separable roles in VPC fate patterning. RGL-1 promotes 2° fate via canonical GEF-dependent activation of RAL-1 and 1° fate via a non-canonical GEF-independent activity. Our genetic epistasis experiments are consistent with RGL-1 functioning in the modulatory 1°-promoting AGE-1/PI3-Kinase-PDK-1-AKT-1 cascade. Additionally, animals without RGL-1 experience 15-fold higher rates of VPC patterning errors compared to the wild type. Yet VPC patterning in RGL-1 deletion mutants is not more sensitive to environmental perturbations. We propose that RGL-1 functions as a “Balanced Switch” that orchestrates opposing 1°- and 2°-promoting modulatory cascades to decrease inappropriate fate decisions. We speculate that such switches are broadly conserved but mostly masked by paralog redundancy or essential genes.

scholarly journals Stage-specific patterns of collagen gene expression during development of Caenorhabditis elegans.

1985 ◽  
Vol 5 (2) ◽  
pp. 363-372 ◽  
Author(s):  
G N Cox ◽  
D Hirsh
Keyword(s):  
Caenorhabditis Elegans ◽  
Protein Composition ◽  
Large Family ◽  
Major Protein ◽  
Mrna Levels ◽  
Mrna Accumulation ◽  
C Elegans ◽  
Collagen Protein ◽  
Protein Components ◽  
Collagen Genes

Collagens are the major protein components of the Caenorhabditis elegans cuticle and are encoded by a large family of 40 to 150 closely related but nonidentical genes. We have determined temporal patterns of mRNA accumulation for a large number of collagen genes by screening recombinant phages and plasmids containing cloned collagen genes under high stringency conditions with 32P-labeled cDNA preparations specific for eggs or three postembryonic molts. We find that collagen mRNA levels are regulated both temporally and quantitatively during C. elegans development. Most genes studied exhibit one of four patterns of mRNA accumulation which correlate with changes in cuticle morphology and collagen protein composition during development. Our results suggest that, in general, there is a progressive activation of new collagen genes during normal development.

scholarly journals MicroRNA-513b-5p targets COL1A1 and COL1A2 associated with the formation and rupture of intracranial aneurysm

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zheng Zheng ◽  
Yan Chen ◽  
Yinzhou Wang ◽  
Yongkun Li ◽  
Qiong Cheng
Keyword(s):  
Cell Death ◽  
Intracranial Aneurysm ◽  
Luciferase Reporter Assay ◽  
Luciferase Reporter ◽  
Control Group ◽  
Type I ◽  
Mrna Levels ◽  
Reporter Assay ◽  
Over Expression ◽  
Tnf Α

AbstractCollagen-type I alpha 1 chain (COL1A1) and COL1A2 are abnormally expressed in intracranial aneurysm (IA), but their mechanism of action remains unclear. This study was performed to investigate the mechanism of COL1A1 and COL1A2 affecting the occurrence and rupture of IA. Quantitative real-time polymerase chain reaction was used to measure the expression of hsa-miR-513b-5p, COL1A1, COL1A2, TNF-α, IL-6, MMP2, MMP3, MMP9 and TIMP4 in patients with ruptured IA (RA) (n = 100), patients with un-ruptured IA (UA) (n = 100), and controls (n = 100). Then, human vascular smooth muscle cells (HASMCs) were cultured, and dual luciferase reporter assay was performed to analyse the targeting relationship between miR-513b-5p and COL1A1 or COL1A2. The effects of the miR-513b-5p mimic and inhibitor on the proliferation, apoptosis, and death of HASMC and the RIP1-RIP3-MLKL and matrix metalloproteinase pathways were also explored. The effect of silencing and over-expression of COL1A1 and COL1A2 on the role of miR-513b-5p were also evaluated. Finally, the effects of TNF-α on miR-513b-5p targeting COL1A1 and COL1A2 were tested. Compared with those in the control group, the serum mRNA levels of miR-513b-5p, IL-6 and TIMP4 were significantly decreased in the RA and UA groups, but COL1A1, COL1A2, TNF-α, IL-1β, MMP2, MMP3 and MMP9 were significantly increased (p < 0.05). Compared with those in the UA group, the expression of COL1A1, COL1A2, TNF-α, IL-1β and MMP9 was significantly up-regulated in the RA group (p < 0.05). Results from the luciferase reporter assay showed that COL1A1 and COL1A were the direct targets of miR-513b-5p. Further studies demonstrated that miR-513b-5p targeted COL1A1/2 to regulate the RIP1-RIP3-MLKL and MMP pathways, thereby enhancing cell death and apoptosis. Over-expression of COL1A1 or COL1A2, rather than silencing COL1A1/2, could improve the inhibitory effect of miR-513b-5p on cell activity by regulating the RIP1-RIP3-MLKL and MMP pathways. Furthermore, over-expression of miR-513b-5p and/or silencing COL1A1/2 inhibited the TNF-α-induced cell proliferation and enhanced the TNF-α-induced cell death and apoptosis. The mechanism may be related to the inhibition of collagen I and TIMP4 expression and promotion of the expression of RIP1, p-RIP1, p-RIP3, p-MLKL, MMP2 and MMP9. MiR-513b-5p targeted the inhibition of COL1A1/2 expression and affected HASMC viability and extracellular mechanism remodelling by regulating the RIP1-RIP3-MLKL and MMP pathways. This process might be involved in the formation and rupture of IA.

Context-specific regulation of lysosomal lipolysis through network-level diverting of transcription factor interactions

2021 ◽  
Vol 118 (41) ◽  
pp. e2104832118
Author(s):  
Vinod K. Mony ◽  
Anna Drangowska-Way ◽  
Reka Albert ◽  
Emma Harrison ◽  
Abbas Ghaddar ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Target Gene ◽  
Specific Nature ◽  
C Elegans ◽  
Functional Interactions ◽  
Genetic Epistasis ◽  
Specific Regulation ◽  
Context Specific ◽  
Factor Interactions ◽  
Multicellular Organisms

Plasticity in multicellular organisms involves signaling pathways converting contexts—either natural environmental challenges or laboratory perturbations—into context-specific changes in gene expression. Congruently, the interactions between the signaling molecules and transcription factors (TF) regulating these responses are also context specific. However, when a target gene responds across contexts, the upstream TF identified in one context is often inferred to regulate it across contexts. Reconciling these stable TF–target gene pair inferences with the context-specific nature of homeostatic responses is therefore needed. The induction of the Caenorhabditis elegans genes lipl-3 and lipl-4 is observed in many genetic contexts and is essential to survival during fasting. We find DAF-16/FOXO mediating lipl-4 induction in all contexts tested; hence, lipl-4 regulation seems context independent and compatible with across-context inferences. In contrast, DAF-16–mediated regulation of lipl-3 is context specific. DAF-16 reduces the induction of lipl-3 during fasting, yet it promotes it during oxidative stress. Through discrete dynamic modeling and genetic epistasis, we define that DAF-16 represses HLH-30/TFEB—the main TF activating lipl-3 during fasting. Contrastingly, DAF-16 activates the stress-responsive TF HSF-1 during oxidative stress, which promotes C. elegans survival through induction of lipl-3. Furthermore, the TF MXL-3 contributes to the dominance of HSF-1 at the expense of HLH-30 during oxidative stress but not during fasting. This study shows how context-specific diverting of functional interactions within a molecular network allows cells to specifically respond to a large number of contexts with a limited number of molecular players, a mode of transcriptional regulation we name “contextualized transcription.”

scholarly journals A neuronal thermostat controls membrane fluidity in C. elegans

2019 ◽  
Author(s):  
L Chauve ◽  
S Murdoch ◽  
F. Masoudzadeh ◽  
F. Hodge ◽  
A. Lopez-Clavijo ◽  
...  
Keyword(s):  
Membrane Fluidity ◽  
Unsaturated Fatty Acids ◽  
Bmp Signaling ◽  
Peripheral Tissues ◽  
Over Expression ◽  
C Elegans ◽  
Shock Response ◽  
Lipid Desaturation ◽  
Neuronal Stress ◽  
Fluidity Of Membranes

SummaryAn organisms’ ability to adapt to heat can be key to its survival. Cells adapt to temperature shifts by adjusting lipid desaturation levels and the fluidity of membranes in a process that is thought to be controlled cell autonomously. We have discovered that subtle, step-wise increments in ambient temperature can lead to the conserved heat shock response being activated in head neurons of C. elegans. This response is exactly opposite to the expression of the lipid desaturase FAT-7 in the worm’s gut. We find that the over-expression of the master regulator of this response, Hsf-1, in head neurons, causes extensive fat remodeling to occur across tissues. These changes include a decrease in FAT-7 expression and a shift in the levels of unsaturated fatty acids in the plasma membrane. These shifts are in line with membrane fluidity requirements to survive in warmer temperatures. We have identified that the cGMP receptor, TAX-2/TAX-4, as well as TGF-β/BMP signaling, as key players in the transmission of neuronal stress to peripheral tissues. This is the first study to suggest that a thermostat-based mechanism can centrally coordinate membrane fluidity in response to warm temperatures across tissues in multicellular animals.

scholarly journals Dietary fatty acids promote lipid droplet diversity through seipin enrichment in an ER subdomain

2018 ◽  
Author(s):  
Zhe Cao ◽  
Yan Hao ◽  
Yiu Yiu Lee ◽  
Pengfei Wang ◽  
Xuesong Li ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Polyunsaturated Fatty Acids ◽  
Lipid Droplet ◽  
Mammalian Cells ◽  
Dietary Fatty Acids ◽  
Fat Storage ◽  
Over Expression ◽  
C Elegans ◽  
Cyclopropane Fatty Acids ◽  
Host Metabolism

AbstractExogenous metabolites from microbial and dietary origins have profound effects on host metabolism. Here, we report that a sub-population of lipid droplets (LDs), which are conserved organelles for fat storage, is defined by metabolites-driven targeting of theC. elegansseipin ortholog, SEIP-1. Loss of SEIP-1 function reduced the size of a subset of LDs while over-expression of SEIP-1 had the opposite effect. Ultrastructural analysis revealed SEIP-1 enrichment in an endoplasmic reticulum (ER) subdomain, which co-purified with LDs. Analyses ofC. elegansand bacterial genetic mutants indicated a requirement of polyunsaturated fatty acids (PUFAs) and microbial cyclopropane fatty acids (CFAs) for SEIP-1 enrichment, as confirmed by dietary supplementation experiments. In mammalian cells, heterologous expression of SEIP-1 promoted lipid droplet expansion from ER subdomains in a conserved manner. Our results suggest that microbial and polyunsaturated fatty acids serve unexpected roles in regulating cellular fat storage by enforcing LD diversity.

Starvation promotes Dictyostelium development by relieving PufA inhibition of PKA translation through the YakA kinase pathway

Development ◽  
1999 ◽  
Vol 126 (14) ◽  
pp. 3263-3274 ◽  
Author(s):  
G.M. Souza ◽  
A.M. da Silva ◽  
A. Kuspa
Keyword(s):  
Cell Cycle ◽  
Protein Kinase ◽  
Mrna Levels ◽  
Wild Type ◽  
Mobility Shift ◽  
Developmental Defects ◽  
C Protein ◽  
Protein Levels ◽  
Cell Extracts ◽  
Puf Protein

When nutrients are depleted, Dictyostelium cells undergo cell cycle arrest and initiate a developmental program that ensures survival. The YakA protein kinase governs this transition by regulating the cell cycle, repressing growth-phase genes and inducing developmental genes. YakA mutants have a shortened cell cycle and do not initiate development. A suppressor of yakA that reverses most of the developmental defects of yakA- cells, but none of their growth defects was identified. The inactivated gene, pufA, encodes a member of the Puf protein family of translational regulators. Upon starvation, pufA- cells develop precociously and overexpress developmentally important proteins, including the catalytic subunit of cAMP-dependent protein kinase, PKA-C. Gel mobility-shift assays using a 200-base segment of PKA-C's mRNA as a probe reveals a complex with wild-type cell extracts, but not with pufA- cell extracts, suggesting the presence of a potential PufA recognition element in the PKA-C mRNA. PKA-C protein levels are low at the times of development when this complex is detectable, whereas when the complex is undetectable PKA-C levels are high. There is also an inverse relationship between PufA and PKA-C protein levels at all times of development in every mutant tested. Furthermore, expression of the putative PufA recognition elements in wild-type cells causes precocious aggregation and PKA-C overexpression, phenocopying a pufA mutation. Finally, YakA function is required for the decline of PufA protein and mRNA levels in the first 4 hours of development. We propose that PufA is a translational regulator that directly controls PKA-C synthesis and that YakA regulates the initiation of development by inhibiting the expression of PufA. Our work also suggests that Puf protein translational regulation evolved prior to the radiation of metazoan species.

Regulation of collagen I gene expression by ras

1992 ◽  
Vol 12 (10) ◽  
pp. 4714-4723
Author(s):  
J L Slack ◽  
M I Parker ◽  
V R Robinson ◽  
P Bornstein
Keyword(s):  
Type I Collagen ◽  
The Body ◽  
Transformed Cells ◽  
Type I ◽  
Mrna Levels ◽  
Oncogenic Ras ◽  
Genes Encoding ◽  
Flanking Region ◽  
Collagen Genes ◽  
I Gene

Although transformation of rodent fibroblasts can lead to dramatic changes in expression of extracellular matrix genes, the molecular basis and physiological significance of these changes remain poorly understood. In this study, we have investigated the mechanism(s) by which ras affects expression of the genes encoding type I collagen. Levels of both alpha 1(I) and alpha 2(I) collagen mRNAs were markedly reduced in Rat 1 fibroblasts overexpressing either the N-rasLys-61 or the Ha-rasVal-12 oncogene. In fibroblasts conditionally transformed with N-rasLys-61, alpha 1(I) transcript levels began to decline within 8 h of ras induction and reached 1 to 5% of control levels after 96 h. In contrast, overexpression of normal ras p21 had no effect on alpha 1(I) or alpha 2(I) mRNA levels. Nuclear run-on experiments demonstrated that the transcription rates of both the alpha 1(I) and alpha 2(I) genes were significantly reduced in ras-transformed cells compared with those in parental cells. In addition, the alpha 1(I) transcript was less stable in transformed cells. Chimeric plasmids containing up to 3.6 kb of alpha 1(I) 5'-flanking DNA and up to 2.3 kb of the 3'-flanking region were expressed at equivalent levels in both normal and ras-transformed fibroblasts. However, a cosmid clone containing the entire mouse alpha 1(I) gene, including 3.7 kb of 5'- and 4 kb of 3'-flanking DNA, was expressed at reduced levels in fibroblasts overexpressing oncogenic ras. We conclude that oncogenic ras regulates the type I collagen genes at both transcriptional and posttranscriptional levels and that this effect, at least for the alpha 1(I) gene, may be mediated by sequences located either within the body of the gene itself or in the distal 3'-flanking region.

scholarly journals Piceatannol, a Natural Stilbene, Extends the Lifespan of Caenorhabditis elegans Under Fasting Through Inhibition of Lipolysis

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 38-38
Author(s):  
Jang Miran ◽  
Zhang Yuan ◽  
Bai Juan ◽  
Jun-Bae An ◽  
Park Yeonhwa ◽  
...  
Keyword(s):  
Lipid Metabolism ◽  
Caenorhabditis Elegans ◽  
Negative Energy ◽  
Hormone Sensitive Lipase ◽  
Pcr Analysis ◽  
Lifespan Extension ◽  
Mrna Levels ◽  
Free Glycerol ◽  
C Elegans ◽  
Glycerol Level

Abstract Objectives Lipolysis is the catabolic process that hydrolyzes triglyceride (TG) to free fatty acids (FFAs) and glycerol under negative energy balance such as fasting. In adipocytes, adipose TG lipase (ATGL), hormone-sensitive lipase (HSL), and monoglyceride lipase play key roles in a series of TG hydrolysis reactions in mammals. However, overly activated adipose lipolysis is believed to contribute to link between obesity and systemic inflammation and oxidative stress. We previously demonstrated that piceatannol (PIC), a natural resveratrol analogue, inhibits adipogenesis in cultured adipocytes and lipogenesis in Caenorhabditis elegans. Furthermore, we showed that PIC extends the lifespan of C. elegans via the insulin/IGF-1 signaling. However, the effects of PIC on lipid metabolism during fasting state is unknown. Methods We conducted Oil-Red-O assay, Enzyme assay (TG and Free glycerol contents), PCR analysis and lifespan assay. Results In this study, we demonstrated that PIC-treated C. elegans exhibited suppressed lipolysis under fasting as judged by increased lipid accumulation and TG levels with decreased free glycerol level. Consistent with these findings, PIC treatment resulted in decreased mRNA levels of genes involved lipolysis such as atgl-1, hosl-1 and aak-2 in fasted C. elegans. Also, PIC treatment augmented fasting-induced lifespan of C. elegans by an increased daf-16 gene expression. However, such effect was abolished when atgl-1, aak-2, and daf-16 mutants were treated with PIC. In addition, we also found that autophagy is required for PIC-induced lifespan in C. elegans during fasting since autophagy inhibitor treatments and autophagy gene deficient worms resulted in blunting the lifespan extension effect of PIC. Conclusions Collectively, our results indicate that PIC contributes to lifespan extension in C. elegans during fasting possibly through regulating lipolysis- and/or autophagy-dependent lipid metabolism. Funding Sources 1. The National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (2019R1A2C1086146) and (2019R1A6A3A03033878) 2. The Rural Development Administration of the Republic of Korea.

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