Temporal profiles of hepatic gene expression in PAR bZip triple knockout mice
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PROVIDER: PRJNA560390 | ENA |
REPOSITORIES: ENA
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Project description:The PAR-domain basic leucine zipper (PAR bZip) transcription factors DBP, TEF, and HLF accumulate in a highly circadian manner in several peripheral tissues, including liver and kidney. Mice devoid of all three of these proteins are born at expected Mendelian ratios, but are epilepsy-prone, age at an accelerated rate and die prematurely. In the hope of identifying PAR bZip target genes whose altered expression might contribute to the high morbidity and mortality of PAR bZip triple knockout mice, we compared the liver and kidney transcriptomes of these animals to those of wild-type or heterozygous mutant mice. These experiments revealed that PAR bZip proteins control the expression of many enzymes and regulators involved in detoxification and drug metabolism, such as cytochrome P450 enzymes, carboxylesterases, and constitutive androstane receptor (CAR). Indeed, PAR bZip triple knockout mice are hypersensitive to xenobiotic compounds, and the deficiency in detoxification may contribute to their early ageing.
2006-12-20 | E-MEXP-565 | biostudies-arrayexpress
Project description:The circadian clock and rhythmic food intake are both important regulators of rhythmic gene expression in the liver. It remains, however, elusive to which extent the circadian clock network and natural feeding rhythms contribute to rhythmic gene expression. To systematically address this question, we developed an algorithm to investigate differential rhythmicity between a varying number of conditions. Mouse knockout models of different parts of the circadian clock network (Bmal1, Cry1/2, and Hlf/Dbp/Tef) exposed to controlled feeding regimens (ad libitum, night restricted feeding) were generated and analyzed for their temporal hepatic transcriptome. A genetical ablation of core loop elements altered feeding patterns that were restored by night restricted feeding. Mainly genes with a high amplitude were driven by the circadian clock but natural feeding patterns equally contributed to rhythmic gene expression with lower amplitude. We observed that Bmal1 and Cry1/2 KOs differed in rhythmic gene expression and identified differences in mean expression levels as a predictor for rhythmic gene expression. In Hlf/Dbp/Tef KO, mRNA levels of Hlf/Dbp/Tef target genes were decreased, albeit rhythmicity was overall preserved potentially due to the activity of the D-Box binding repressor NFIL3. Genes that lost rhythmicity in Hlf/Dbp/Tef KOs were identified to be no direct targets of PARbZip factors and presumably lost rhythmicity due to indirect effects. Collectively, our findings provide unprecedent insights into the diurnal transcriptome in mouse liver and defines the contribution of subloops of the circadian clock network and natural feeding cycles. The developed algorithm and a webapp to browse the outcomes of the study are publicly available to serve as a resource for the scientific community.
2020-12-03 | GSE135875 | GEO
Project description:Found PAR bZip target genes. The loss of circadian PAR bZip transcription factors results in epilepsy, DBP (albumin D-site-binding protein), HLF (hepatic leukemia factor), and TEF (thyrotroph embryonic factor) are the three members of the PAR bZip (proline and acidic amino acid-rich basic leucine zipper) transcription factor family. All three of these transcriptional regulatory proteins accumulate with robust circadian rhythms in tissues with high amplitudes of clock gene expression, such as the suprachiasmatic nucleus (SCN) and the liver. However, they are expressed at nearly invariable levels in most brain regions, in which clock gene expression only cycles with low amplitude. Here we show that mice deficient for all three PAR bZip proteins are highly susceptible to generalized spontaneous and audiogenic epilepsies that frequently are lethal. Transcriptome profiling revealed pyridoxal kinase (Pdxk) as a target gene of PAR bZip proteins in both liver and brain. Pyridoxal kinase converts vitamin B6 derivatives into pyridoxal phosphate (PLP), the coenzyme of many enzymes involved in amino acid and neurotransmitter metabolism. PAR bZip-deficient mice show decreased brain levels of PLP, serotonin, and dopamine, and such changes have previously been reported to cause epilepsies in other systems. Hence, the expression of some clock-controlled genes, such as Pdxk, may have to remain within narrow limits in the brain. This could explain why the circadian oscillator has evolved to generate only low-amplitude cycles in most brain regions.; find REV-ERB ALPHA target genes
2010-06-22 | E-TABM-726 | biostudies-arrayexpress
Project description:Prostate apoptosis response-4 (Par-4) is a tumor suppressor protein that is extensively investigated in cancer. The objective of this study is to determine the physiological function of Par-4 in normal cells. Our findings indicated that genetic loss of Par-4 in mice primarily results in adipocyte hypertrophy and obesity, and secondary leads to hepatic steatosis and insulin resistance. Moreover, we noted that Par-4 is downregulated in human subjects who are likely to become obese in the future, thereby serving as a predictor of obesity. Importantly, ChIP-Seq indicated that MDM2 is a target of Par-4 protein, which is known to function as a transcriptional coregulator. We show that Par-4 loss upregulates MDM2 target protein p53, and that p53 further induces complement factor C3 and its proteolytic fragment acylation stimulating protein (ASP), an adipokine that is known to be causally associated with obesity. These studies led to the identification of the Par-4-MDM2-p53-C3/ASP axis in regulation of obesity by Par-4.
2022-03-25 | GSE159147 | GEO
Project description:Characterisation of the temporal hepatic transcriptome at subcellular level
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Project description:Blood cell formation is a tightly regulated process initiated from a rare population of multipotent hematopoietic stem cells. Subsequent differentiation proceeds in a hierarchical manner with the generation of intermediate progenitor cells, in which alternative lineage potentials become gradually restricted. A deeper understanding of these events is crucial not only to understand normal blood cell formation, but also for leukemia, where a defining feature is inappropriate differentiation. Here, we identified Hepatic Leukemia Factor (Hlf) as being highly and selectively expressed in primitive multipotent hematopoietic stem and progenitors. We demonstrate that Hlf is a strong negative regulator of B-, NK- and T cell development and instructs multipotent progenitors to adopt a myeloid fate in a cell autonomous manner; phenotypes underwritten by the induction of myeloid affiliated transcriptional programs, the concomitant ablation of lymphoid gene programs and a genome-wide binding spectra that involved active enhancers of myeloid-competent cells. Collectively, our studies establish Hlf as a key regulator of the earliest lineage-commitment events at the transition from multipotency to lineage-restricted progeny, with implications for both normal and malignant hematopoiesis. Gene expression profiling of control or Hlf/Hlf lentivirus infected GMLPs (2 replicates per group) and Hlf inducible GMLPs maintained for 4 days on OP9 stroma in the presence or absence of doxycycline (2 replicates per group)
2016-06-12 | E-GEOD-69858 | biostudies-arrayexpress
Project description:Blood cell formation is a tightly regulated process initiated from a rare population of multipotent hematopoietic stem cells. Subsequent differentiation proceeds in a hierarchical manner with the generation of intermediate progenitor cells, in which alternative lineage potentials become gradually restricted. A deeper understanding of these events is crucial not only to understand normal blood cell formation, but also for leukemia, where a defining feature is inappropriate differentiation. Here, we identified Hepatic Leukemia Factor (Hlf) as being highly and selectively expressed in primitive multipotent hematopoietic stem and progenitors. We demonstrate that Hlf is a strong negative regulator of B-, NK- and T cell development and instructs multipotent progenitors to adopt a myeloid fate in a cell autonomous manner; phenotypes underwritten by the induction of myeloid affiliated transcriptional programs, the concomitant ablation of lymphoid gene programs and genome-wide binding spectra that involved active enhancers of myeloid-competent cells. Collectively, our studies establish Hlf as a key regulator of the earliest lineage-commitment events at the transition from multipotency to lineage-restricted progeny, with implications for both normal and malignant hematopoiesis.
2016-07-11 | GSE69817 | GEO
Project description: Not available
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Project description:Temporal and functional determinants of intra-hepatic vascular homeostatic specialization
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Project description:In mammals, homologous chromosomes rarely pair outside meiosis. One exception is the X chromosome, which transiently pairs during X-chromosome inactivation (XCI). How two chromosomes find each other in 3D space is not known. Here, we reveal a required interaction between the X-inactivation center (Xic) and the telomere in mouse embryonic stem (ES) cells. The subtelomeric, pseudoautosomal regions (PARs) of the two sex chromosomes (X and Y) also undergo pairing in both female and male cells. PARs transcribe a class of telomeric RNA, dubbed PAR-TERRA, which accounts for a vast majority of all TERRA transcripts. PAR-TERRA binds throughout the genome, including to the PAR and Xic. During X-chromosome pairing, PAR-TERRA anchors the Xic to the PAR, creating a ‘tetrad’ of pairwise homologous interactions (Xic–Xic, PAR–PAR, and Xic–PAR). Xic pairing occurs within the tetrad. Depleting PAR-TERRA abrogates pairing and blocks initiation of XCI, whereas autosomal PAR-TERRA induces ectopic pairing. We propose a ‘constrained diffusion model’ in which PAR-TERRA creates an interaction hub to guide Xic homology searching during XCI.
2017-07-10 | GSE69887 | GEO