Danio rerio
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ABSTRACT:
PROVIDER: PRJNA162305 | ENA |
REPOSITORIES: ENA
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Project description:The liver circadian clock is reprogrammed by nutritional challenge through the rewiring of specific transcriptional pathways. As the gut microbiota is tightly connected to host metabolism, whose coordination is governed by the circadian clock, we explored whether gut microbes influence circadian homeostasis and how they distally control the peripheral clock in the liver. Using fecal transplant procedures we reveal that, in response to high fat diet, the gut microbiota drives PPARγ-mediated activation of newly oscillatory transcriptional programs in the liver. Moreover, antibiotics treatment prevents PPARγ-driven transcription in the liver, underscoring the essential role of gut microbes in clock reprogramming and hepatic circadian homeostasis. Thus, a specific molecular signature characterizes the influence of the gut microbiome in the liver, leading to the transcriptional rewiring of hepatic metabolism. We used microarray to quantify the tissue specific expression level of circadian genes in terms of total RNA.
2016-06-04 | GSE82250 | GEO
Project description:Recent reports indicate hypoxia influences the clock through the transcriptional activities of hypoxia inducible factors (HIFs) at clock genes. Unexpectedly, we uncover a profound disruption of the circadian clock and diurnal transcriptome when hypoxic cells are permitted to acidify, recapitulating the tumor microenvironment. Buffering against acidification or inhibiting lactic acid production fully rescues circadian oscillation. Acidification of several human and murine cell lines, as well as primary murine T cells, suppresses mechanistic target of rapamycin complex 1 (mTORc1) signaling, a key regulator of translation in response to metabolic status. We find acid drives peripheral redistribution of normally perinuclear lysosomes, inhibiting lysosome-bound mTOR. Restoring mTORc1 signaling and the translation it governs rescues clock oscillation, revealing a model in which lactic acid produced during the cellular metabolic response to hypoxia suppresses the circadian clock through diminished translation of clock constituents.
2018-06-02 | GSE101988 | GEO
Project description:Mammalian circadian rhythms are based on coupled transcriptional-translational feedback loops driven by the transcription factors CLOCK and BMAL1. Chromatin remodeling mechanisms are essential for the proper timing and extent of circadian gene expression. We report that the S-adenosylhomocysteine (SAH) hydrolysing enzyme AHCY binds to CLOCK-BMAL1 at chromatin and drives circadian transcription by promoting cyclic H3K4 trimethylation and recruitment of BMAL1 to chromatin.
2020-02-01 | GSE125720 | GEO
Project description:Mammalian circadian rhythms are based on coupled transcriptional-translational feedback loops driven by the transcription factors CLOCK and BMAL1. Chromatin remodeling mechanisms are essential for the proper timing and extent of circadian gene expression. We report that the S-adenosylhomocysteine (SAH) hydrolysing enzyme AHCY binds to CLOCK-BMAL1 at chromatin and drives circadian transcription by promoting cyclic H3K4 trimethylation and recruitment of BMAL1 to chromatin.
2021-01-11 | GSE126851 | GEO
Project description:The mammalian circadian clock is a molecular oscillator composed of a feedback loop that involves transcriptional activators CLOCK and BMAL1, and repressors Cryptochrome (CRY) and Period (PER). Here we show that a direct CLOCK-BMAL1 target gene, Gm129, is a novel regulator of the feedback loop. ChIP analysis revealed that the CLOCK:BMAL1:CRY1 complex strongly occupies the promoter region of Gm129. Both mRNA and protein levels of GM129 exhibit high amplitude circadian oscillations in mouse liver, and Gm129 gene encodes a nuclear-localized protein that directly interacts with BMAL1 and represses CLOCK:BMAL1 activity. In vitro and in vivo protein-DNA interaction results demonstrate that, like CRY1, GM129 functions as a repressor by binding to the CLOCK:BMAL1 complex on DNA. Although Gm129-/- or Cry1-/- Gm129-/- mice retain a robust circadian rhythm, the peaks of Nr1d1 and Dbp mRNAs in liver exhibit significant phase delay compared to control. Our results suggest that, in addition to CRYs and PERs, GM129 protein contributes to the transcriptional feedback loop by modulating CLOCK:BMAL1 activity as a transcriptional repressor. Examination of 3 transcriptional regulators in mouse liver
2014-01-07 | E-GEOD-53828 | biostudies-arrayexpress
Project description:Using larval zebrafish as a model system, we applied a genome-wide transcriptome approach that allowed us to investigate circadian gene expression that can be associated with various tissues and cell types. Our analysis of circadian gene regulatory network revealed a general principle: circadian clock controls diverse aspects of circadian physiology through transcriptional cascade of transcription factors (TFs). As a proof of this principle, we focused on microphthalmia-associated transcription factor a (mitfa), a dark-induced TF controlling melanogenesis in melanocytes. We demonstrated experimentally that there is a circadian rhythm of melanin synthesis mediated by mitfa. The circadian rhythm of mitfa is in turn driven by both endogenous clock and external light/dark cycle. The circadian rhythm of melanin synthesis may play an important role in zebrafish’s adaptation to daily cycle of lighting condition in the environment.
2012-04-26 | GSE37332 | GEO
Project description:Vegetally localised Vrtn functions as a novel repressor to modulate bmp2b transcription during dorsoventral patterning in zebrafish
| PRJNA400171 | ENA
Project description:The circadian clock regulates behavioural and physiological processes in a 24-h cycle. The nuclear receptors REV-ERBa and REV-ERBb are involved in the cell-autonomous circadian transcriptional/translational feedback loops as transcriptional repressors. A number of studies have also demonstrated a pivotal role of REV-ERBs in regulation of metabolic, neuronal, and inflammatory functions including bile acid metabolism, lipid metabolism, and production of inflammatory cytokines. Given the multifunctional role of REV-ERBs, it is important to elucidate the mechanism through which REV-ERBs exert their functions. To this end, we established a Rev-erba/Rev-erbb double-knockout mouse embryonic stem (ES) cell model and analyzed the circadian clock and clock-controlled output gene expressions. A comprehensive mRNA-seq analysis revealed that the complete knockout of both Rev-erba and Rev-erbb does not abrogate expression rhythms of E-box-regulated core clock genes but drastically changes a diverse set of other rhythmically-expressed output genes. Of note, REV-ERBa/b deficiency does not compromise circadian expression rhythms of PER2, while REV-ERB target genes, Bmal1 and Npas2, are significantly upregulated. This study emphasizes REV-ERBs function to form an essential link between the circadian clock and a wide variety of cellular physiological functions.
2019-07-29 | GSE125696 | GEO
Project description:Circadian clocks generate endogenous rhythms in most organisms from cyanobacteria to humans and facilitate entrainment to environmental diurnal cycles, thus conferring a fitness advantage. Both transcriptional and posttranslational mechanisms are prominent in the basic network architecture of circadian systems. Posttranscriptional regulation, including mRNA processing, is emerging as a critical step for the clock function. However, little is known about the molecular mechanisms linking RNA metabolism to the circadian clock network. Here we report that a conserved SNW/SKIP domain protein, SKIP, a splicing factor and component of the spliceosome, is involved in the posttranscriptional regulation of circadian clock genes in Arabidopsis. Mutation in SKIP lengthens the circadian period in a temperature sensitive manner, affects light input and the sensitivity of light resetting to the clock. SKIP physically interacts with the spliceosomal splicing factor SR45 and associates with the pre-mRNA of clock genes, such as PRR7 and PRR9, and is necessary for the regulation of their alternative splicing and mRNA maturation. Genome-wide investigations reveal that SKIP functions in regulating alternative splicing of many genes, presumably through modulating recognition or cleavage of 5' and 3' splicing site. Our study addresses a fundamental question on how the mRNA splicing machinery contributes to circadian clock functions at a posttranscriptional level. Our findings revealed that AtSKIP is a splicing factor and a component of spliceosome. To further investigate effects of mutation in SKIP on the genome-wide changes of alternative splicing, we performed ultra-highthroughput RNA sequencing, using 10-day old seedlings. Two biological replicates for both wild type (Col-0) and skip-2 were designed.
2012-12-13 | E-GEOD-32216 | biostudies-arrayexpress