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Project description:Liver development involves dramatic gene expression changes mediated by transcriptional and post-transcriptional control. Here, we show that the Cnot deadenylase complex plays a crucial role in liver functional maturation. The Cnot3 gene encodes an essential subunit of the Cnot complex. Mice lacking Cnot3 in liver have reduced body and liver masses, and they display anemia and severe liver damage. Histological analyses indicate that Cnot3-deficient (Cnot3-/- ) hepatocytes are irregular in size and morphology, resulting in formation of abnormal sinusoids. We observe hepatocyte death, increased abundance of mitotic and mononucleate hepatocytes, and inflammation. Cnot3-/- livers show increased expression of immune response-related, cell cycle-regulating and immature liver genes, while many genes relevant to liver functions, such as oxidation-reduction, lipid metabolism and mitochondrial function, decrease, indicating impaired liver functional maturation. Highly expressed mRNAs possess elongated poly(A) tails and are stabilized in Cnot3-/- livers, concomitant with an increase of the proteins they encode. In contrast, transcription of liver function-related mRNAs was lower in Cnot3-/- livers. We detect efficient suppression of Cnot3 protein postnatally, demonstrating the crucial contribution of mRNA decay to postnatal liver functional maturation.
| S-EPMC6398447 | biostudies-literature
Project description:Liver development requires Cnot complex-mediated decay of mRNAs encoding cell cycle, cell division, and immature liver genes
| PRJNA471815 | ENA
Project description:BackgroundThe major aim of this study is to investigate whether CDC6 (cell division cycle 6), a replication origin recognition complex component, plays a role in retinal neovascularization, and if so, to explore the underlying mechanisms.MethodsIn this study, we used a variety of approaches including cellular and moleculer biological methodologies as well as global and tissue-specific knockout mice in combination with an oxygen-induced retinopathy model to study the role of CDC6 in retinal neovascularization.ResultsVEGFA (vascular endothelial growth factor A)-induced CDC6 expression in a time-dependent manner in human retinal microvascular endothelial cells. In addition, VEGFA-induced CDC6 expression was dependent on PLCβ3 (phospholipase Cβ3)-mediated NFATc1 (nuclear factor of activated T cells c1) activation. Furthermore, while siRNA-mediated depletion of PLCβ3, NFATc1, or CDC6 levels blunted VEGFA-induced human retinal microvascular endothelial cell angiogenic events such as proliferation, migration, sprouting, and tube formation, CDC6 overexpression rescued these effects in NFATc1-deficient mouse retinal microvascular endothelial cells. In accordance with these observations, global knockdown of PLCβ3 or endothelial cell-specific deletion of NFATc1 or siRNA-mediated depletion of CDC6 levels substantially inhibited oxygen-induced retinopathy-induced retinal sprouting and neovascularization. In addition, retroviral-mediated overexpression of CDC6 rescued oxygen-induced retinopathy-induced retinal neovascularization from inhibition in PLCβ3 knockout mice and in endothelial cell-specific NFATc1-deficient mice.ConclusionsThe above observations clearly reveal that PLCβ3-mediated NFATc1 activation-dependent CDC6 expression plays a crucial role in VEGFA/oxygen-induced retinopathy-induced retinal neovascularization.
| S-EPMC8957605 | biostudies-literature
Project description:Centromeric histone CENP-A, a variant of canonical histone H3, plays a central role in proper chromosome segregation. Loading of CENP-A at centromeres is cell cycle-regulated: parental CENP-A is deposited at centromeres during S phase, whereas newly synthesized CENP-A is deposited during later stages of the cell cycle. The mechanisms involved in deposition of CENP-A at centromeres during S phase remain poorly understood. In fission yeast, loading of CENP-A during S phase is regulated by the GATA-type factor, Ams2. Here we show that the Dos1/2-Cdc20 complex, previously characterized as a silencing complex essential for inheritance of H3K9 methylation during S phase, is also required for localization of CENP-A(cnp1) at centromeres at this stage. Disruption of Dos1 (also known as Raf1/Clr8/Cmc1), Dos2 (also known as Raf2/Clr7/Cmc2), or Cdc20, a DNA polymerase epsilon subunit, results in dissociation of CENP-A from centromeres and mislocalization of the protein to noncentromeric sites. All three mutants display spindle disorganization and mitotic defects. Inactivation of Dos1 or Cdc20 also results in accumulation of noncoding RNA transcripts from centromeric cores, a feature common to mutants affecting kinetochore integrity. We further find that Dos1 physically associates with Ams2 and is required for the association of Ams2 with centromeric cores during S phase. Finally, we show that Dos2 associates with centromeric cores during S phase and that its recruitment to centromeric cores depends on Cdc20. This study identifies a physical link between DNA replication and CENP-A assembly machinery and provides mechanistic insight into how CENP-A is faithfully inherited during S phase.
| S-EPMC3545758 | biostudies-literature
Project description:The eukaryotic translation initiation factor 2 (eIF2) is central to the onset of protein synthesis and its modulation in response to physiological demands. eIF2, a heterotrimeric G-protein, is activated by guanine nucleotide exchange to deliver the initiator methionyl-tRNA to the ribosome. Here we report that assembly of the eIF2 complex in vivo depends on Cdc123, a cell proliferation protein conserved among eukaryotes. Mutations of CDC123 in budding yeast reduced the association of eIF2 subunits, diminished polysome levels, and increased GCN4 expression indicating that Cdc123 is critical for eIF2 activity. Cdc123 bound the unassembled eIF2? subunit, but not the eIF2 complex, and the C-terminal domain III region of eIF2? was both necessary and sufficient for Cdc123 binding. Alterations of the binding site revealed a strict correlation between Cdc123 binding, the biological function of eIF2?, and its ability to assemble with eIF2? and eIF2?. Interestingly, high levels of Cdc123 neutralized the assembly defect and restored the biological function of an eIF2? mutant. Moreover, the combined overexpression of eIF2 subunits rescued an otherwise inviable cdc123 deletion mutant. Thus, Cdc123 is a specific eIF2 assembly factor indispensable for the onset of protein synthesis. Human Cdc123 is encoded by a disease risk locus, and, therefore, eIF2 biogenesis control by Cdc123 may prove relevant for normal cell physiology and human health. This work identifies a novel step in the eukaryotic translation initiation pathway and assigns a biochemical function to a protein that is essential for growth and viability of eukaryotic cells.
| S-EPMC3724614 | biostudies-literature
Project description:To study the role of the exonuclease Xrn1 in translational control, we performed ribosome profiling and RNA-seq in Xrn1-depleted cells. By using an auxin-inducible degron, we were able to study immediate effects of Xrn1 depletion in translational control. Therefore, we could overcome experimental limitations associated to stable deletion mutants.
2019-02-08 | GSE109734 | GEO
Project description:In contrast to the deregulated hepatocellular division that is a feature of many hepatic diseases and malignancies, physiologic liver growth during embryonic development and after partial hepatectomy (PH) in adults is characterized by tightly controlled cell proliferation. We used forward genetic screening in zebrafish to test the hypothesis that a similar genetic program governs physiologic liver growth during hepatogenesis and regeneration after PH. We identified the uhrf1 gene, a cell cycle regulator and transcriptional activator of top2a expression, as required for hepatic outgrowth and embryonic survival. By developing a methodology to perform PH on adult zebrafish, we found that liver regeneration inuhrf1+/- adult animals is impaired.uhrf1 transcript levels dramatically increase after PH in both mice, and zebrafish and top2a is not up-regulated in uhrf1+/- livers after PH. This indicates that uhrf1 is required for physiologic liver growth in both embryos and adults and illustrates that zebrafish livers regenerate.
| S-EPMC1785278 | biostudies-literature
Project description:During mitosis, the genome is transformed from a decondensed, transcriptionally active state to a highly condensed, transcriptionally inactive state. Mitotic chromosome reorganization is marked by the general attenuation of transcription on chromosome arms, yet how the cell regulates nuclear and chromatin-associated RNAs after chromosome condensation and nuclear envelope breakdown is unknown. SAF-A/hnRNPU is an abundant nuclear protein with RNA-to-DNA tethering activity, coordinated by two spatially distinct nucleic acid-binding domains. Here we show that RNA is evicted from prophase chromosomes through Aurora-B-dependent phosphorylation of the SAF-A DNA-binding domain; failure to execute this pathway leads to accumulation of SAF-A-RNA complexes on mitotic chromosomes, defects in metaphase chromosome alignment, and elevated rates of chromosome missegregation in anaphase. This work reveals a role for Aurora-B in removing chromatin-associated RNAs during prophase and demonstrates that Aurora-B-dependent relocalization of SAF-A during cell division contributes to the fidelity of chromosome segregation.
| S-EPMC7549315 | biostudies-literature
Project description:Effects of aripiprazole on dopamine regulation are being tested as a treatment for patients with a dual diagnosis of schizophrenia and addictions, often cocaine dependence. Aripiprazole has one of the fewest side-effects among the second-generation antipsychotics. Nevertheless, severe aripiprazole hepatotoxicity was reported in persons with a history of cocaine and alcohol abuse. Here we report that therapeutically relevant aripiprazole concentrations, equal to laboratory alert levels in patients' serum, reduce the rate of hepatocytes' division. This could be an underlying mechanism of severe liver injury development in the patients with a history of alcohol and cocaine abuse, the two hepatotoxic agents that require increased ability of liver self-regeneration. Monitoring liver functions is, therefore, important in the cases when aripiprazole is co-prescribed or used with drugs with potential hepatotoxic effects.
| S-EPMC7588089 | biostudies-literature
Project description:Since cdc48 mutants were isolated by the first genetic screens for cell division cycle (cdc) mutants in yeast, the requirement of the chaperone-like ATPase Cdc48/p97 during cell division has remained unclear. Here, we discover an unanticipated function for Caenorhabditis elegans CDC-48 in DNA replication linked to cell cycle control. Our analysis of the CDC-48(UFD-1/NPL-4) complex identified a general role in S phase progression of mitotic cells essential for embryonic cell division and germline development of adult worms. These developmental defects result from activation of the DNA replication checkpoint caused by replication stress. Similar to loss of replication licensing factors, DNA content is strongly reduced in worms depleted for CDC-48, UFD-1, and NPL-4. In addition, these worms show decreased DNA synthesis and hypersensitivity toward replication blocking agents. Our findings identified a role for CDC-48(UFD-1/NPL-4) in DNA replication, which is important for cell cycle progression and genome stability.
| S-EPMC2529102 | biostudies-literature