Project description:Many reports support a link between circadian rhythm and renal diseases. However, these dysregulated clock-controlled genes in kidney have mainly focused on the protein-coding genes. Here, we try to identify these circadian long-coding RNA (lncRNAs) in renal tissue.
Project description:BACKGROUND: The daily gene expression oscillations that underlie mammalian circadian rhythms show striking differences between tissues and involve post-transcriptional regulation. Both aspects remain poorly understood. We have used ribosome profiling to explore the contribution of translation efficiency to temporal gene expression in kidney, and contrasted our findings with liver data available from the same mice. RESULTS: Rhythmic translation of constantly abundant mRNAs affects largely nonoverlapping transcript sets with distinct phase clustering in the two organs. Moreover, tissue differences in translation efficiency modulate the timing and amount of protein biosynthesis from rhythmic mRNAs, consistent with organ-specificity in clock output gene repertoires and rhythmicity parameters. Our comprehensive datasets provided insights into translational control beyond temporal regulation. Between tissues, many transcripts show differences in translation efficiency, which are, however, of markedly smaller scale than mRNA abundance differences. Tissue-specific changes in translation efficiency are associated with specific transcript features and, intriguingly, globally counteracted and compensated transcript abundance variations, leading to higher similarity at the level of protein biosynthesis between both tissues. CONCLUSIONS: We show that tissue-specificity in rhythmic gene expression extends to the translatome and contributes to define the identities, the phases and the expression levels of rhythmic protein biosynthesis. Moreover, translational compensation of transcript abundance divergence leads to overall higher similarity at the level of protein production across organs. The unique resources provided through our study will serve to address fundamental questions of post-transcriptional control and differential gene expression in vivo.
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.
Project description:The circadian clock and feeding rhythms are both important regulators of rhythmic gene expression in the liver. To further dissect the respective contributions of feeding and the clock, we analyzed differential rhythmicity of liver tissue samples across several conditions. We developed a statistical method tailored to compare rhythmic liver messenger RNA (mRNA) expression in mouse knockout models of multiple clock genes, as well as PARbZip output transcription factors (Hlf/Dbp/Tef). Mice were exposed to ad libitum or night-restricted feeding under regular light-dark cycles. During ad libitum feeding, genetic ablation of the core clock attenuated rhythmic-feeding patterns, which could be restored by the night-restricted feeding regimen. High-amplitude mRNA expression rhythms in wild-type livers were driven by the circadian clock, but rhythmic feeding also contributed to rhythmic gene expression, albeit with significantly lower amplitudes. We observed that Bmal1 and Cry1/2 knockouts differed in their residual rhythmic gene expression. Differences in mean expression levels between wild types and knockouts correlated with rhythmic gene expression in wild type. Surprisingly, in PARbZip knockout mice, the mean expression levels of PARbZip targets were more strongly impacted than their rhythms, potentially due to the rhythmic activity of the D-box-repressor NFIL3. Genes that lost rhythmicity in PARbZip knockouts were identified to be indirect targets. Our findings provide insights into the diurnal transcriptome in mouse liver as we identified the differential contributions of several core clock regulators. In addition, we gained more insights on the specific effects of the feeding-fasting cycle.
Project description:Here we studied the leaf transcriptome in maize,<br>throughout a cycle of 10 h darkness and 14 h light to look for rhythmic patterns<br>of gene expression.
Project description:Genome-wide rhythmic occupancy of RNA polymerase II (RNAPII) is highly coordinated with rhythmic genes expression. Rhythmic RNAPII binding dynamically modulates diurnal 3D genome architecture remodeling with 91% of the chromatin interactions were altered. The rhythmic genes cluster at the 8:00 (AM) circadian phase form spatial interacting clusters in turn assist coordinated rhythmic gene expression, while non-rhythmic genes tend to tether together and contribute to expression at 20:00 (PM) circadian window. Target genes and associated cis-binding motifs of transcription factors enrichment points to the existence of subnuclear organization hub enriched around the TFs. RNAPII-associated chromatin interaction domains (CIDs) are under circadian control, and static CIDs with common node genes but changed connecting genes along the circadian cycle, reveal they may function as distinct clock components in the interconnected circuits between morning and evening. Core circadian clock genes related chromatin connectivity networks reveal a compact and highly connected chromatin architecture serving to coordinate gene expression in the morning, whereas a scattered, loose chromatin architecture coordinates PM gene expression. Our findings uncover novel diurnal fundamental genome folding principles in plants, and reveal the distinct higher-order chromosome organization that is crucial for coordinating diurnal dynamics of transcriptional regulation.
Project description:Genome-wide rhythmic occupancy of RNA polymerase II (RNAPII) is highly coordinated with rhythmic genes expression. Rhythmic RNAPII binding dynamically modulates diurnal 3D genome architecture remodeling with 91% of the chromatin interactions were altered. The rhythmic genes cluster at the 8:00 (AM) circadian phase form spatial interacting clusters in turn assist coordinated rhythmic gene expression, while non-rhythmic genes tend to tether together and contribute to expression at 20:00 (PM) circadian window. Target genes and associated cis-binding motifs of transcription factors enrichment points to the existence of subnuclear organization hub enriched around the TFs. RNAPII-associated chromatin interaction domains (CIDs) are under circadian control, and static CIDs with common node genes but changed connecting genes along the circadian cycle, reveal they may function as distinct clock components in the interconnected circuits between morning and evening. Core circadian clock genes related chromatin connectivity networks reveal a compact and highly connected chromatin architecture serving to coordinate gene expression in the morning, whereas a scattered, loose chromatin architecture coordinates PM gene expression. Our findings uncover novel diurnal fundamental genome folding principles in plants, and reveal the distinct higher-order chromosome organization that is crucial for coordinating diurnal dynamics of transcriptional regulation.