An evolutionary epigenetic clock in plants [Biostress]
Ontology highlight
ABSTRACT:
ORGANISM(S): Arabidopsis thaliana
PROVIDER: GSE223861 | GEO | 2024/01/11
REPOSITORIES: GEO
Similar Datasets
Project description:Molecular clocks are the basis for dating the divergence between lineages over macro-evolutionary timescales (~104-108 years). However, classical DNA-based clocks tick too slowly to inform us about the recent past. Here, we demonstrate that stochastic DNA methylation changes at a subset of cytosines in plant genomes possess a clock-like behavior. This ‘epimutation-clock’ is orders of magnitude faster than DNA-based clocks and enables phylogenetic explorations on a scale of years to centuries. We show experimentally that epimutation-clocks recapitulate known topologies and branching times of intra-species phylogenetic trees in the selfing plant A. thaliana and the clonal seagrass Z. marina, which represent the two primary modes of plant reproduction. This discovery will open new possibilities for high-resolution temporal studies of plant biodiversity.
2024-01-11 | GSE223810 | GEO
Project description:The establishment of highly accurate aging clocks based on DNA methylation highlighted the strong link between epigenetic alterations and aging. However, connecting methylation clocks to physiological changes is not straightforward. Transcriptomics and proteomics clocks on the other hand are directly connected to cellular function, yet they do not allow us to understand underlying epigenetic mechanisms. We hypothesize that chromatin accessibility, a readout that integrates many epigenetic mechanisms, may bridge epigenetic changes with their downstream effects in aging. To demonstrate that chromatin accessibility can predict age, we generated chromatin accessibility profiles from peripheral blood mononuclear cells (PBMCs) of 157 human donors, aged 20 to 74 and used them to construct a novel aging clock. Our clock predicted age with a root mean squared error of 7.69 years, a median absolute error of 5.69 years and a correlation of 0.83. Moreover, by comparing our chromatin accessibility data to matched transcriptomic profiles, we show that the genomic sites selected by our clock drive changes in transcription during aging. This chromatin accessibility clock could therefore be used to better understand the mechanisms driving the process of aging and evaluate anti-aging interventions.
2022-12-01 | GSE193141 | GEO
Project description:The establishment of highly accurate aging clocks based on DNA methylation highlighted the strong link between epigenetic alterations and aging. However, connecting methylation clocks to physiological changes is not straightforward. Transcriptomics and proteomics clocks on the other hand are directly connected to cellular function, yet they do not allow us to understand underlying epigenetic mechanisms. We hypothesize that chromatin accessibility, a readout that integrates many epigenetic mechanisms, may bridge epigenetic changes with their downstream effects in aging. To demonstrate that chromatin accessibility can predict age, we generated chromatin accessibility profiles from peripheral blood mononuclear cells (PBMCs) of 157 human donors, aged 20 to 74 and used them to construct a novel aging clock. Our clock predicted age with a root mean squared error of 7.69 years, a median absolute error of 5.69 years and a correlation of 0.83. Moreover, by comparing our chromatin accessibility data to matched transcriptomic profiles, we show that the genomic sites selected by our clock drive changes in transcription during aging. This chromatin accessibility clock could therefore be used to better understand the mechanisms driving the process of aging and evaluate anti-aging interventions.
2022-12-01 | GSE193140 | GEO
Project description:The mammalian circadian system consists of a central clock in the brain that synchronizes clocks in peripheral tissues. While the hierarchy between the central and peripheral clocks is well established, peripheral clocks are largely viewed as a group and little is known regarding their specificity and functional organization. We employed feeding paradigms in conjunction with liver-specific clock-deficient murine model to map disparities and potential interactions between peripheral clocks. We found that peripheral clocks largely differ in their response to feeding-time. In view of its prominent role in nutrient processing, we hypothesized that the liver-clock instigate the response of peripheral clocks to feeding. Although the liver-clock did not affect the rhythmicity of clocks in other peripheral tissues, it strongly modulated their transcriptional rhythmicity upon daytime feeding. Overall, our findings suggest a role for the liver-clock in buffering feeding-related signals that affect rhythmicity of other peripheral tissues upon nutrient challenge, irrespective of their clocks.
2021-01-29 | GSE159135 | GEO
Project description:Circadian clocks coordinate time-of-day specific metabolic and physiological processes to maximize performance and fitness. In addition to light, which is considered the strongest time cue to entrain animal circadian clocks, metabolic input has emerged as an important signal for clock modulation and entrainment, especially in peripheral clocks. Circadian clock proteins have been to be substrates of O-GlcNAcylation, a nutrient sensitive post-translational modification (PTM), and the interplay between clock protein O-GlcNAcylation and other PTMs, like phosphorylation, is expected to facilitate the regulation of circadian physiology by metabolic signals. Here, we used mass spectrometry proteomics to identify PTMs on PERIOD, the key biochemical timer of the Drosophila clock, over the circadian cycle.
2017-11-23 | MSV000081736 | MassIVE
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:Although circadian clocks oscillate in most cells, it has been difficult to detect canonical expression of clock genes in fetal rodent tissues, including the fetal liver. The oscillation status of fetal clocks and the maternal influence on these clocks have not yet been conclusively defined. Here we report that, when the mother mice are under restricted feeding, the expression rhythms of several clock genes can be detected in fetal mouse livers. Those rhythms, although of low amplitude, reversed their profiles under opposite feeding cycles, suggesting maternal entrainment of the weak fetal liver clocks. However, Bmal1 could show biphasic expression in the fetal livers. The expression of some metabolic genes (e.g. Insig1) also showed biphasic daily changes in fetal livers, possibly as a result of interactions between the unique in utero milieu and the fetal liver clocks. Regular rhythms of clock gene expression were detected in dissociated fetal hepatocytes in culture. Differential expression of metabolic genes were found between fetal and adult livers, suggesting that metabolic features affected clock amplitude. Genome-wide differences in DNA methylation were also found between adult and fetal livers. Some of those epigenetic changes were likely critical for the developmental changes in clock amplitudes.
2015-04-01 | GSE50034 | GEO
Project description:RNA-seq reads from the selfing species Arabidopsis thaliana were produced from flowers to study the consequences of the transition from the ancestral state (outcrossing) to the derived state (selfing). This was done in the context of examining another species in the Arabidopsis genus (A. lyrata) and another species pair (Capsella rubella versus Capsella grandiflora, which are selfing and outcrossing, respectively). These samples were generated to complement part of this larger study. Briefly, the shift from outcrossing to selfing is common in flowering plants, but neither the genomic consequences nor the speed with which they appear are well understood. An excellent model for understanding the evolution of self fertilization is provided by Capsella rubella, which became self-compatible <200,000 years ago. We present a reference genome for the species, and compare RNA expression and polymorphism patterns between C. rubella and its outcrossing progenitor C. grandiflora. There is a clear shift in the expression of genes associated with flowering phenotypes; a similar shift is seen in the related genus Arabidopsis, where self-fertilization evolved about 1 million years ago. DNA sequence polymorphisms distinguishing the two Capsella species reveal rapid genome-wide relaxation of purifying selection in C. rubella but without a concomitant change in transposable element abundance. Overall, we document that the transition to selfing may be typified by shifts in expression for genes that function in pollen and flower development, along with a measurable reduction of purifying selection.
2013-04-02 | GSE45685 | GEO
Project description:Mammalian circadian clocks precisely control the rhythms of behavior and physiology, and can be reset by various environmental signals. While the light-dark (LD) cycle resets the master clock, timed food intake is a potent synchronizer of peripheral clocks. As the largest metabolic organ, the liver sensitively responds to the food signals and secrets hepatokines, leading to the robust regulation of metabolic and clock processes. However, it remains unknown which hepatokine mediates the food-driven resetting of the liver clock independent of the master clock. In our current study, we clustered high-throughput RNA sequencing results to screen out candidate genes that mediate the food-driven resetting of the liver clock
2019-06-27 | GSE133342 | GEO
Project description:Organisms have adapted to the changing environmental conditions within the 24h cycle of the day by temporally segregating tissue physiology to the optimal time of the day. On the cellular level temporal segregation of physiological processes is established by the circadian clock, a Bmal1 dependent transcriptional oscillator network. The circadian clocks within individual cells of a tissue are synchronised by environmental signals, mainly light, in order to reach temporally segregated physiology on the tissue level. However, how light mediated synchronisation of peripheral tissue clocks is achieved mechanistically and whether circadian clocks in different organs are autonomous or interact with each other to achieve rhythmicity is unknown. Here we report that light can synchronise core circadian clocks in two peripheral tissues, the epidermis and liver hepatocytes, even in the complete absence of functional clocks in any other tissue within the whole organism. On the other hand, tissue extrinsic circadian clock rhythmicity is necessary to retain rhythmicity of the epidermal clock in the absence of light, proving for the first time that the circadian clockwork acts as a memory of time for the synchronisation of peripheral clocks in the absence of external entrainment signals. Furthermore, we find that tissue intrinsic Bmal1 is an important regulator of the epidermal differentiation process whose deregulation leads to a premature aging like phenotype of the epidermis. Thus, our results establish a new model for the segregation of peripheral tissue physiology whereby the synchronisation of peripheral clocks is acquired by the interaction of a light dependent but circadian clock independent pathway with circadian clockwork dependent cues.
2019-03-25 | GSE115104 | GEO