Defining the Independence of the Liver Circadian Clock
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE132659 | GEO | 2019/06/13
REPOSITORIES: GEO
Similar Datasets
Project description:Virtually every mammalian tissue exhibits rhythmic expression in thousands of genes, which activate tissue-specific processes at appropriate times of the day. Much of this rhythmic expression is thought to be driven cell-autonomously by molecular circadian clocks present throughout the body. However, increasing evidence suggests that systemic signals, and more specifically rhythmic food intake (RFI), can regulate rhythmic gene expression independently of the circadian clock. To determine the relative contribution of cell autonomous clocks versus RFI in the regulation of rhythmic gene expression, we developed a system that allows long-term manipulation of the daily rhythm of food intake in the mouse, and analyzed liver gene expression by RNA-Seq in mice fed ad libitum, only at night, or arrhythmically (mouse eating 1/8th of their daily food intake every 3 hours). We show that 70% of the cycling mouse liver transcriptome loses rhythmicity under arrhythmic feeding. Remarkably, this loss of rhythmic gene expression under arrhythmic feeding is independent of the liver circadian clock, which continues to exhibit normal oscillations in core clock gene expression. Many genes that lose rhythmicity participate in the regulation of metabolic processes such as lipogenesis and glycogenesis, likely contributing to an increased sensitivity to insulin that was observed in arrhythmically-fed mice. We also show that night-restricted feeding significantly increases the number of rhythmically expressed genes as well as the amplitude of the rhythms. Together, these results indicate that metabolic transcription factors control a large fraction of the rhythmic mouse liver transcriptome, and demonstrate that systemic signals driven by rhythmic food intake play a more important role than the cell-autonomous circadian clock in driving rhythms in liver gene expression and metabolic functions.
2019-04-25 | GSE118967 | GEO
Project description:The circadian clock in mammals temporally coordinates physiological and behavioural processes to anticipate daily rhythmic changes in their environment. Chronic disruption to circadian rhythms (e.g., through ageing or shift work) is thought to contribute to a multitude of diseases, including degeneration of the musculoskeletal system. The intervertebral disc (IVD) in the spine contains circadian clocks which control ~6% of the transcriptome in a rhythmic manner, including key genes involved in extracellular matrix (ECM) homeostasis. However, it remains largely unknown to what extent the local IVD molecular clock is required to drive rhythmic gene transcription and IVD physiology. In this work, we identified profound age-related changes of ECM microarchitecture and an endochondral ossification-like phenotype in the annulus fibrosus (AF) region of the IVD in the Col2a1-Bmal1 knockout mice. Reported here is the circadian time series RNA-Seq of the whole IVD in Bmal1 knockout mice.
2023-08-17 | E-MTAB-13083 | biostudies-arrayexpress
Project description:Circadian (~24 hour) clocks exist in almost all types of living organism and play a fundamental role in regulating daily physiological and behavioural processes. The transcription factor BMAL1 (ARNTL) is thought to be one of the principal drivers of the molecular clock in mammals since its deletion abolishes 24-hour activity patterning, an important physiological output of the clockwork. However, whether or not Bmal1-/- mice can nevertheless display molecular 24-hour rhythms is unknown. Here, we determined whether Bmal1 function is necessary for daily molecular oscillations in two tissues – skin fibroblasts and liver. Unexpectedly, both tissues exhibited robust 24-hour oscillations over 2-3 days in the absence of any exogenous synchronizers such as daily light or temperature cycles. This demonstrates a competent 24-hour molecular pacemaker in Bmal1 knockouts. Indeed, molecular oscillations were pervasive throughout the transcriptome, proteome and phosphoproteome of Bmal1-/- mice. In particular, several proteins exhibited rhythmic phosphorylation in both Bmal1-proficient and -deficient cells, highlighting an unanticipated role for post-translational regulators in 24-hour rhythms in the absence of any known clock mechanisms.
2020-02-17 | PXD009243 | Pride
Project description:Over the past decade, genome-wide assays have underscored the broad sweep of circadian gene expression. A substantial fraction of the transcriptome undergoes oscillations in many organisms and tissues, which governs the many biochemical, physiological and behavioral functions under circadian control. Based predominantly on the transcription feedback loops important for core circadian timekeeping, it is commonly assumed that this widespread mRNA cycling reflects circadian transcriptional cycling. To address this issue, we directly measured dynamic changes in mouse liver transcription using Nascent-Seq. Many genes are rhythmically transcribed over the 24h day, which include precursors of several non-coding RNAs as well as the expected set of core clock genes. Surprisingly however, nascent RNA rhythms overlap poorly with mRNA abundance rhythms assayed by RNA-seq. This is because most mouse liver genes with rhythmic mRNA expression manifest poor transcriptional rhythms, indicating a prominent role of post-transcriptional regulation in setting mRNA cycling amplitude. To gain further insight into circadian transcriptional regulation, we also characterized the rhythmic transcription of liver genes targeted by the transcription factors CLOCK and BMAL1; they directly target other core clock genes and sit at the top of the molecular circadian clock hierarchy in mammals. CLK:BMAL1 rhythmically bind at the same discrete phase of the circadian cycle to all target genes, which not surprisingly have a much higher percentage of rhythmic transcription than the genome as a whole. However, there is a surprisingly heterogeneous set of cycling transcription phases of direct target genes, which even include core clock genes. This indicates a disconnect between rhythmic DNA binding and the peak of transcription, which is likely due to other transcription factors that collaborate with CLK:BMAL1. In summary, the application of Nascent-Seq to a mammalian tissue provides surprising insights into the rhythmic control of gene expression and should have broad applications beyond the analysis of circadian rhythms. CLK and BMAL1 DNA binding profile in the mouse liver at ZT8, sequenced along an Input sample using GAII (ChIP-Seq) Supplementary file ChIPSeq_Mouse_Liver_Processed_data_Table1.txt represents annotated CLK and BMAL1 peaks.
2012-11-10 | E-GEOD-36874 | biostudies-arrayexpress
Project description:The mammalian circadian clock relies on the master genes CLOCK (CLK) and BMAL1 and drives rhythmic gene expression to regulate biological functions under circadian control. We recently uncovered a surprising disconnect between the rhythmic binding of CLK:BMAL1 on DNA and the transcription of its target genes, suggesting that they are regulated by as yet uncharacterized mechanisms. Here we show that rhythmic CLK:BMAL1 DNA binding promotes rhythmic chromatin opening. The underlying mechanisms include CLK:BMAL1 binding to nucleosomes and rhythmic chromatin modifications, including the incorporation of the histone variant H2A.Z. This rhythmic chromatin remodeling mediates the rhythmic binding of other transcription factors adjacent to CLK:BMAL1, suggesting that the activity and the tissue-specific expression of these other transcription factors contribute to the genome-wide CLK:BMAL1 heterogeneous transcriptional output. These data therefore indicate that the clock regulation of transcription relies on the rhythmic regulation of chromatin accessibility and suggest that the concept of pioneer function extends to acute gene regulation, well beyond the current confines of developmental/cell specification. H2A.Z ChIP-Seq signal in the mouse liver over 6 time points of the 24h light:dark cycle, in wild-type and Bmal1-/- mice. Libraries containing a mononucleosome insert were sequenced using Ilumina HiSeq2000.
2014-01-06 | E-GEOD-47143 | biostudies-arrayexpress
Project description:The mammalian circadian clock relies on the master genes CLOCK (CLK) and BMAL1 and drives rhythmic gene expression to regulate biological functions under circadian control. We recently uncovered a surprising disconnect between the rhythmic binding of CLK:BMAL1 on DNA and the transcription of its target genes, suggesting that they are regulated by as yet uncharacterized mechanisms. Here we show that rhythmic CLK:BMAL1 DNA binding promotes rhythmic chromatin opening. The underlying mechanisms include CLK:BMAL1 binding to nucleosomes and rhythmic chromatin modifications, including the incorporation of the histone variant H2A.Z. This rhythmic chromatin remodeling mediates the rhythmic binding of other transcription factors adjacent to CLK:BMAL1, suggesting that the activity and the tissue-specific expression of these other transcription factors contribute to the genome-wide CLK:BMAL1 heterogeneous transcriptional output. These data therefore indicate that the clock regulation of transcription relies on the rhythmic regulation of chromatin accessibility and suggest that the concept of pioneer function extends to acute gene regulation, well beyond the current confines of developmental/cell specification. Mouse liver nucleosome profile assayed by MNase-Seq over 6 time points of the 24h light:dark cycle (4 wild-type and 4 Bmal1-/- mice per time point). Illumina libraries containing a mononucleosome insert were sequenced using Ilumina HiSeq2000.
2014-01-06 | E-GEOD-47142 | biostudies-arrayexpress
Project description:The mammalian circadian clock relies on the master genes CLOCK (CLK) and BMAL1 and drives rhythmic gene expression to regulate biological functions under circadian control. We recently uncovered a surprising disconnect between the rhythmic binding of CLK:BMAL1 on DNA and the transcription of its target genes, suggesting that they are regulated by as yet uncharacterized mechanisms. Here we show that rhythmic CLK:BMAL1 DNA binding promotes rhythmic chromatin opening. The underlying mechanisms include CLK:BMAL1 binding to nucleosomes and rhythmic chromatin modifications, including the incorporation of the histone variant H2A.Z. This rhythmic chromatin remodeling mediates the rhythmic binding of other transcription factors adjacent to CLK:BMAL1, suggesting that the activity and the tissue-specific expression of these other transcription factors contribute to the genome-wide CLK:BMAL1 heterogeneous transcriptional output. These data therefore indicate that the clock regulation of transcription relies on the rhythmic regulation of chromatin accessibility and suggest that the concept of pioneer function extends to acute gene regulation, well beyond the current confines of developmental/cell specification. Mouse liver CLK ChIP-Seq signal on Mnase-digested or sonicated chromatin, at 2 different time point (ZT22 and ZT06) from the same mice. Libraries were sequenced using Ilumina HiSeq2000. For Mnase-digested chromatin, libraries contained a mononucleosome insert (e.g., ~147bp), whereas the insert was ~150-300bp for sonicated chromatin.
2014-01-06 | E-GEOD-47144 | biostudies-arrayexpress
Project description:The mammalian circadian clock system is made up of individual cell and tissue clocks that function as a coherent network, however it remains unclear which rhythmic functions of the liver clock are autonomous or rely on clocks in other tissues. Here, using mice which only have a functioning liver clock, we investigate the autonomous vs non-autonomous reatures of the liver clock and diurnal rhythmicity in the liver
2019-06-11 | GSE117134 | GEO
Project description:The human osteosarcoma cell line U2OS contains a functional circadian clock but expresses only a few rhythmic genes. We identified by ChIP-seq analysis 3040 binding sites of the circadian transcription factors BMAL1, CLOCK, and CRY1 in the genome of U2OS cells, comparable to the number found in highly rhythmic tissues like liver.
2016-02-11 | GSE44236 | GEO
Project description:The human osteosarcoma cell line U2OS contains a functional circadian clock but expresses only a few rhythmic genes. We identified by ChIP-seq analysis 3040 binding sites of the circadian transcription factors BMAL1, CLOCK, and CRY1 in the genome of U2OS cells, comparable to the number found in highly rhythmic tissues like liver. ChIP was performed as described previously (Rey et al, 2011; doi:10.1371/journal.pbio.1000595) using confluent desynchronized U2OS cells and BMAL1, CLOCK, and CRY1-antibodies. Immunoprecipitated chromatin (10 ng DNA of 8 independent BMAL1 ChIPs with enrichment levels > 80-fold, 9 ng DNA of a CRY1 ChIP with 10-fold enrichment, and 8 ng DNA of a CLOCK ChIP with 40-fold enrichment) was used for library preparation. Three lanes of the BMAL1 library, and one lane each of the CRY1 and CLOCK library were sequenced on the Illumina Genome Analyzer IIx using Single-Read Cluster Generation Kit and 36 Cycle Sequencing Kit v2 (Lausanne Genomics Technologies Facility).
2016-02-11 | E-GEOD-44236 | biostudies-arrayexpress