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1.
Cell Mol Life Sci ; 80(3): 61, 2023 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-36763212

RESUMO

BRAF mutations have been found in gliomas which exhibit abnormal electrophysiological activities, implying their potential links with the ion channel functions. In this study, we identified the Drosophila potassium channel, Slowpoke (Slo), the ortholog of human KCNMA1, as a critical factor involved in dRafGOF glioma progression. Slo was upregulated in dRafGOF glioma. Knockdown of slo led to decreases in dRafGOF levels, glioma cell proliferation, and tumor-related phenotypes. Overexpression of slo in glial cells elevated dRaf expression and promoted cell proliferation. Similar mutual regulations of p-BRAF and KCNMA1 levels were then recapitulated in human glioma cells with the BRAF mutation. Elevated p-BRAF and KCNMA1 were also observed in HEK293T cells upon the treatment of 20 mM KCl, which causes membrane depolarization. Knockdown KCNMA1 in these cells led to a further decrease in cell viability. Based on these results, we conclude that the levels of p-BRAF and KCNMA1 are co-dependent and mutually regulated. We propose that, in depolarized glioma cells with BRAF mutations, high KCNMA1 levels act to repolarize membrane potential and facilitate cell growth. Our study provides a new strategy to antagonize the progression of gliomas as induced by BRAF mutations.


Assuntos
Glioma , Subunidades alfa do Canal de Potássio Ativado por Cálcio de Condutância Alta , Proteínas Proto-Oncogênicas B-raf , Animais , Humanos , Drosophila/metabolismo , Glioma/genética , Células HEK293 , Subunidades alfa do Canal de Potássio Ativado por Cálcio de Condutância Alta/genética , Subunidades alfa do Canal de Potássio Ativado por Cálcio de Condutância Alta/metabolismo , Canais de Potássio/genética , Proteínas Proto-Oncogênicas B-raf/genética , Proteínas Proto-Oncogênicas B-raf/metabolismo
2.
Nucleic Acids Res ; 49(22): 13108-13121, 2021 12 16.
Artigo em Inglês | MEDLINE | ID: mdl-34878141

RESUMO

Mutations in genes encoding mitochondrial aminoacyl-tRNA synthetases are linked to diverse diseases. However, the precise mechanisms by which these mutations affect mitochondrial function and disease development are not fully understood. Here, we develop a Drosophila model to study the function of dFARS2, the Drosophila homologue of the mitochondrial phenylalanyl-tRNA synthetase, and further characterize human disease-associated FARS2 variants. Inactivation of dFARS2 in Drosophila leads to developmental delay and seizure. Biochemical studies reveal that dFARS2 is required for mitochondrial tRNA aminoacylation, mitochondrial protein stability, and assembly and enzyme activities of OXPHOS complexes. Interestingly, by modeling FARS2 mutations associated with human disease in Drosophila, we provide evidence that expression of two human FARS2 variants, p.G309S and p.D142Y, induces seizure behaviors and locomotion defects, respectively. Together, our results not only show the relationship between dysfunction of mitochondrial aminoacylation system and pathologies, but also illustrate the application of Drosophila model for functional analysis of human disease-causing variants.


Assuntos
Deficiências do Desenvolvimento/genética , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Proteínas Mitocondriais/genética , Mutação , Fenilalanina-tRNA Ligase/genética , RNA de Transferência/genética , Convulsões/genética , Animais , Linhagem Celular , Deficiências do Desenvolvimento/enzimologia , Modelos Animais de Doenças , Proteínas de Drosophila/deficiência , Drosophila melanogaster/enzimologia , Técnicas de Silenciamento de Genes , Humanos , Microscopia Eletrônica de Transmissão , Mitocôndrias/genética , Mitocôndrias/metabolismo , Mitocôndrias/ultraestrutura , Proteínas Mitocondriais/deficiência , Fosforilação Oxidativa , Fenilalanina-tRNA Ligase/deficiência , RNA de Transferência/metabolismo , Convulsões/enzimologia , Aminoacilação de RNA de Transferência
3.
J Biol Chem ; 294(14): 5666-5676, 2019 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-30760524

RESUMO

Atg101 is an autophagy-related gene identified in worms, flies, mice, and mammals, which encodes a protein that functions in autophagosome formation by associating with the ULK1-Atg13-Fip200 complex. In the last few years, the critical role of Atg101 in autophagy has been well-established through biochemical studies and the determination of its protein structure. However, Atg101's physiological role, both during development and in adulthood, remains less understood. Here, we describe the generation and characterization of an Atg101 loss-of-function mutant in Drosophila and report on the roles of Atg101 in maintaining tissue homeostasis in both adult brains and midguts. We observed that homozygous or hemizygous Atg101 mutants were semi-lethal, with only some of them surviving into adulthood. Both developmental and starvation-induced autophagy processes were defective in the Atg101 mutant animals, and Atg101 mutant adult flies had a significantly shorter lifespan and displayed a mobility defect. Moreover, we observed the accumulation of ubiquitin-positive aggregates in Atg101 mutant brains, indicating a neuronal defect. Interestingly, Atg101 mutant adult midguts were shorter and thicker and exhibited abnormal morphology with enlarged enterocytes. Detailed analysis also revealed that the differentiation from intestinal stem cells to enterocytes was impaired in these midguts. Cell type-specific rescue experiments disclosed that Atg101 had a function in enterocytes and limited their growth. In summary, the results of our study indicate that Drosophila Atg101 is essential for tissue homeostasis in both adult brains and midguts. We propose that Atg101 may have a role in age-related processes.


Assuntos
Proteínas Relacionadas à Autofagia/metabolismo , Proteínas de Drosophila/metabolismo , Enterócitos/metabolismo , Homeostase , Intestinos , Longevidade , Neurônios/metabolismo , Animais , Proteínas Relacionadas à Autofagia/genética , Proteínas de Drosophila/genética , Drosophila melanogaster , Mutação com Perda de Função
4.
J Biol Chem ; 294(50): 19292-19305, 2019 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-31685661

RESUMO

Nuclear modifier genes have been proposed to modify the phenotypic expression of mitochondrial DNA mutations. Using a targeted exome-sequencing approach, here we found that the p.191Gly>Val mutation in mitochondrial tyrosyl-tRNA synthetase 2 (YARS2) interacts with the tRNASer(UCN) 7511A>G mutation in causing deafness. Strikingly, members of a Chinese family bearing both the YARS2 p.191Gly>Val and m.7511A>G mutations displayed much higher penetrance of deafness than those pedigrees carrying only the m.7511A>G mutation. The m.7511A>G mutation changed the A4:U69 base-pairing to G4:U69 pairing at the aminoacyl acceptor stem of tRNASer(UCN) and perturbed tRNASer(UCN) structure and function, including an increased melting temperature, altered conformation, instability, and aberrant aminoacylation of mutant tRNA. Using lymphoblastoid cell lines derived from symptomatic and asymptomatic members of these Chinese families and control subjects, we show that cell lines harboring only the m.7511A>G or p.191Gly>Val mutation revealed relatively mild defects in tRNASer(UCN) or tRNATyr metabolism, respectively. However, cell lines harboring both m.7511A>G and p.191Gly>Val mutations displayed more severe defective aminoacylations and lower tRNASer(UCN) and tRNATyr levels, aberrant aminoacylation, and lower levels of other tRNAs, including tRNAThr, tRNALys, tRNALeu(UUR), and tRNASer(AGY), than those in the cell lines carrying only the m.7511A>G or p.191Gly>Val mutation. Furthermore, mutant cell lines harboring both m.7511A>G and p.191Gly>Val mutations exhibited greater decreases in the levels of mitochondrial translation, respiration, and mitochondrial ATP and membrane potentials, along with increased production of reactive oxygen species. Our findings provide molecular-level insights into the pathophysiology of maternally transmitted deafness arising from the synergy between tRNASer(UCN) and mitochondrial YARS mutations.


Assuntos
Mitocôndrias/enzimologia , Mutação , RNA de Transferência de Serina/genética , Tirosina-tRNA Ligase/genética , Povo Asiático , Células Cultivadas , DNA Mitocondrial/genética , DNA Mitocondrial/metabolismo , Feminino , Humanos , Masculino , Linhagem , Fenótipo , Tirosina-tRNA Ligase/metabolismo
5.
FASEB J ; 33(2): 2646-2658, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30307770

RESUMO

CD133 (AC133/prominin-1) has been identified as a stem cell marker and a putative cancer stem cell marker in many solid tumors. Its biologic function and molecular mechanisms remain largely elusive. Here, we show that a fly mutant for prominin-like, a homolog of mammalian CD133, shows a larger body size and excess weight accompanied with higher fat deposits as compared with the wild type. The expression levels of prominin-like are mediated by ecdysone signaling where its protein levels increase dramatically in the fat body during metamorphosis. Prominin-like mutants exhibit higher Drosophila insulin-like peptide 6 (di lp6) levels during nonfeeding stages and increased Akt/ Drosophila target of rapamycin (dTOR) signaling. On an amino acid-restricted diet, prominin-like mutants exhibit a significantly larger body size than the wild type does, similar to that which occurs upon the activation of the dTOR pathway in the fat body. Our data suggest that prominin-like functions by suppressing TOR and dilp6 signaling to control body size and weight. The identification of the physiologic function of prominin-like in Drosophila may provide valuable insight into the understanding of the metabolic function of CD133 in mammals.-Zheng, H., Zhang, Y., Chen, Y., Guo, P., Wang, X., Yuan, X., Ge, W., Yang, R., Yan, Q., Yang, X., Xi, Y. Prominin-like, a homolog of mammalian CD133, suppresses di lp6 and TOR signaling to maintain body size and weight in Drosophila.


Assuntos
Antígeno AC133/metabolismo , Tamanho Corporal , Peso Corporal , Proteínas de Drosophila/antagonistas & inibidores , Drosophila melanogaster/fisiologia , Regulação da Expressão Gênica no Desenvolvimento , Receptores Proteína Tirosina Quinases/antagonistas & inibidores , Somatomedinas/antagonistas & inibidores , Antígeno AC133/genética , Animais , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Mutação , Receptores Proteína Tirosina Quinases/genética , Receptores Proteína Tirosina Quinases/metabolismo , Transdução de Sinais , Somatomedinas/genética , Somatomedinas/metabolismo
6.
RNA Biol ; 17(9): 1277-1283, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32397794

RESUMO

Maintenance of motor neuron structure and function is crucial in development and motor behaviour. However, the genetic regulatory mechanism of motor neuron function remains less well understood. In the present study, we identify a novel neuroprotective role of the microRNA miR-969 in Drosophila motor neurons. miR-969 is highly expressed in motor neurons. Loss of miR-969 results in early-onset and age-progressive locomotion impairment. Flies lacking miR-969 also exhibit shortened lifespan. Moreover, miR-969 is required in motor neurons. We further identify kay as a functionally important target of miR-969. Together, our results indicate that miR-969 can protect motor neuron function by limiting kay activity in Drosophila.


Assuntos
Regulação da Expressão Gênica , MicroRNAs/genética , Neurônios Motores/metabolismo , Fatores de Transcrição/metabolismo , Regiões 3' não Traduzidas , Animais , Sobrevivência Celular/genética , Drosophila/genética , Imunofluorescência , Modelos Biológicos , Mutação , Interferência de RNA , RNA Mensageiro/genética
7.
Biochem J ; 476(4): 759-768, 2019 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-30733258

RESUMO

Control of organ size is a fundamental aspect in biology and plays important roles in development. The Hippo pathway is a conserved signaling cascade that controls tissue and organ size through the regulation of cell proliferation and apoptosis. Here, we report on the roles of Hcf (host cell factor), the Drosophila homolog of Host cell factor 1, in regulating the Hippo signaling pathway. Loss-of-Hcf function causes tissue undergrowth and the down-regulation of Hippo target gene expression. Genetic analysis reveals that Hcf is required for Hippo pathway-mediated overgrowth. Mechanistically, we show that Hcf associates with the histone H3 lysine-4 methyltransferase Trithorax-related (Trr) to maintain H3K4 mono- and trimethylation. Thus, we conclude that Hcf positively regulates Hippo pathway activity through forming a complex with Trr and controlling H3K4 methylation.


Assuntos
Proteínas de Drosophila/metabolismo , Histona-Lisina N-Metiltransferase/metabolismo , Histonas/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Transdução de Sinais , Animais , Linhagem Celular , Proteínas de Drosophila/genética , Drosophila melanogaster , Histona-Lisina N-Metiltransferase/genética , Histonas/genética , Peptídeos e Proteínas de Sinalização Intracelular/genética , Metilação , Proteínas Serina-Treonina Quinases/genética
8.
Development ; 143(1): 35-44, 2016 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-26586222

RESUMO

The mechanism for the basal targeting of the Miranda (Mira) complex during the asymmetric division of Drosophila neuroblasts (NBs) is yet to be fully understood. We have identified conserved Phosphotyrosyl phosphatase activator (PTPA) as a novel mediator for the basal localization of the Mira complex in larval brain NBs. In mutant Ptpa NBs, Mira remains cytoplasmic during early mitosis and its basal localization is delayed until anaphase. Detailed analyses indicate that PTPA acts independent of and before aPKC to localize Mira. Mechanistically, our data show that the phosphorylation status of the T591 residue determines the subcellular localization of Mira and that PTPA facilitates the dephosphorylation of T591. Furthermore, PTPA associates with the Protein phosphatase 4 complex to mediate localization of Mira. On the basis of these results, a two-step process for the basal localization of Mira during NB division is revealed: cortical association of Mira mediated by the PTPA-PP4 complex is followed by apical aPKC-mediated basal restriction.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila/embriologia , Células-Tronco Neurais/metabolismo , Neurogênese/fisiologia , Proteína Quinase C/metabolismo , Animais , Divisão Celular Assimétrica/fisiologia , Linhagem Celular , Fosfoproteínas Fosfatases/metabolismo , Fosforilação
9.
FASEB J ; 31(5): 1964-1975, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28126734

RESUMO

In Drosophila, fat-body remodeling accompanied with fat mobilization is an ecdysone-induced dynamic process that only occurs during metamorphosis. Here, we show that the activated Drosophila platelet-derived growth factor/VEGF receptor (PVR) is sufficient to induce shape changes in the fat body, from thin layers of tightly conjugated polygonal cells to clusters of disaggregated round-shaped cells. These morphologic changes are reminiscent of those seen during early pupation upon initiation of fat-body remodeling. Activation of PVR also triggers an early onset of lipolysis and mobilization of internal storage, as revealed by the appearance of small lipid droplets and up-regulated lipolysis-related genes. We found that PVR displays a dynamic expression pattern in the fat body and peaks at the larval-prepupal transition under the control of ecdysone signaling. Removal of PVR, although it does not prevent ecdysone-induced fat-body remodeling, causes ecdysone signaling to be up-regulated. Our data reveal that PVR is active in a dual-secured mechanism that involves an ecdysone-induced fat-body remodeling pathway and a reinforced PVR pathway for effective lipid mobilization. Ectopic expression of activated c-kit-the mouse homolog of PVR in the Drosophila fat body-also results in a similar phenotype. This may suggest a novel function of c-kit as it relates to lipid metabolism in mammals.-Zheng, H., Wang, X., Guo, P., Ge, W., Yan, Q., Gao, W., Xi, Y., Yang, X. Premature remodeling of fat body and fat mobilization triggered by platelet-derived growth factor/VEGF receptor in Drosophila.


Assuntos
Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Corpo Adiposo/metabolismo , Regulação da Expressão Gênica no Desenvolvimento/genética , Receptores Proteína Tirosina Quinases/metabolismo , Animais , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Genes de Insetos/genética , Metamorfose Biológica/fisiologia , Proteínas Proto-Oncogênicas c-kit/metabolismo , Receptores Proteína Tirosina Quinases/genética , Ativação Transcricional/genética
10.
J Mol Cell Biol ; 2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38719542

RESUMO

Defects in the FAcilitates Chromatin Transcription (FACT) complex, a histone chaperone composed of SSRP1 and SUPT16H, are implicated in intellectual disability. Here, we reveal that the FACT complex promotes glycolysis and sustains the correct cell fate of neural stem cells/neuroblasts in the Drosophila 3rd instar larval central brain. We show that the FACT complex binds to the promoter region of the estrogen-related receptor (ERR) gene and positively regulates ERR expression. ERR is known to act as an aerobic glycolytic switch by upregulating the enzymes required for glycolysis. Dysfunction of the FACT complex leads to the downregulation of ERR transcription, resulting in a decreased ratio of glycolysis to oxidative phosphorylation (G/O) in neuroblasts. Consequently, neuroblasts exhibit smaller cell sizes, lower proliferation potential, and altered cell fates. Overexpression of ERR or suppression of mitochondrial oxidative phosphorylation in neuroblasts increases the relative G/O ratio and rescues defective phenotypes caused by dysfunction of the FACT complex. Thus, the G/O ratio, mediated by the FACT complex, plays a crucial role in neuroblast cell fate maintenance. Our study may shed light on the mechanism by which mutations in the FACT complex lead to intellectual disability in humans.

11.
Cell Death Differ ; 30(7): 1811-1828, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37322264

RESUMO

Persistent R-loop accumulation can cause DNA damage and lead to genome instability, which contributes to various human diseases. Identification of molecules and signaling pathways in controlling R-loop homeostasis provide important clues about their physiological and pathological roles in cells. Here, we show that NKAP (NF-κB activating protein) is essential for preventing R-loop accumulation and maintaining genome integrity through forming a protein complex with HDAC3. NKAP depletion causes DNA damage and genome instability. Aberrant accumulation of R-loops is present in NKAP-deficient cells and leads to DNA damage and DNA replication fork progression defects. Moreover, NKAP depletion induced R-loops and DNA damage are dependent on transcription. Consistently, the NKAP interacting protein HDAC3 exhibits a similar role in suppressing R-loop associated DNA damage and replication stress. Further analysis uncovers that HDAC3 functions to stabilize NKAP protein, independent of its deacetylase activity. In addition, NKAP prevents R-loop formation by maintaining RNA polymerase II pausing. Importantly, R-loops induced by NKAP or HDAC3 depletion are processed into DNA double-strand breaks by XPF and XPG endonucleases. These findings indicate that both NKAP and HDAC3 are novel key regulators of R-loop homeostasis, and their dysregulation might drive tumorigenesis by causing R-loop associated genome instability.


Assuntos
Instabilidade Genômica , Estruturas R-Loop , Humanos , Dano ao DNA , Quebras de DNA de Cadeia Dupla , Replicação do DNA , Proteínas Repressoras/genética
12.
Biomark Res ; 11(1): 12, 2023 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-36717926

RESUMO

BACKGROUND: Epithelial ovarian cancer (EOC) is a highly prevalent disease that rapidly metastasizes and has poor prognosis. Most women are in the middle or late stages when diagnosed and have low survival rates. Recently, long non-coding RNAs (lncRNAs) were recognized to play pivotal roles in the development of EOC. METHODS: The expression of SLC25A21 antisense RNA 1 (SLC25A21-AS1) and Polypyrimidine Tract Binding Protein 3 (PTBP3) in EOC cells was assessed via qPCR. The proliferation activity of these cells was detected by EdU and Cell counting kit-8 (CCK8) assays, while the death rate of apoptotic cells and the cell cycle were detected by flow cytometry. Detection of cell transfer rate by transwell assay. Protein expression was measured through western blotting. Interactions between SLC25A21-AS1 and PTBP3 were detected through RNA immunoprecipitation (RIP), IF-FISH co-localization experiments and electrophoretic mobility shift assay (EMSA). The in vivo importance of SLC25A21-AS1 as a tumor suppressor modulator was assessed using murine xenograft models. RESULTS: The lncRNA SLC25A21-AS1 has negligible expression in ovarian cancer tissues compared with that in normal ovarian tissues. A series of functional experiments revealed that the upregulation of SLC25A21-AS1 markedly blocked the proliferation and metastasis of EOC cells in vitro, while its downregulation had the opposite effect. Overexpression of SLC25A21-AS1 in a nude mouse model of EOC in vivo resulted in slower tumor growth and weakened metastatic potential. Moreover, SLC25A21-AS1 reduced the protein stability of PTBP3 and promoted its degradation. A series of subsequent experiments found that SLC25A21-AS1 inhibits EOC cell proliferation and metastasis by modulating PTBP3 through the ubiquitin-proteasome pathway and that the combination of SLC25A21-AS1 and PTBP3 provides the necessary conditions for the for the function to be realized. CONCLUSIONS: Our research reveals the effect of SLC25A21-AS1 in EOC development and suggests SLC25A21-AS1 can serve as a prognostic target by promoting the degradation of PTBP3 to improve patient survival.

13.
Cell Death Discov ; 9(1): 288, 2023 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-37543696

RESUMO

Regulation of protein translation initiation is tightly associated with cell growth and survival. Here, we identify Paip1, the Drosophila homolog of the translation initiation factor PAIP1, and analyze its role during development. Through genetic analysis, we find that loss of Paip1 causes reduced protein translation and pupal lethality. Furthermore, tissue specific knockdown of Paip1 results in apoptotic cell death in the wing imaginal disc. Paip1 depletion leads to increased proteotoxic stress and activation of the integrated stress response (ISR) pathway. Mechanistically, we show that loss of Paip1 promotes phosphorylation of eIF2α via the kinase PERK, leading to apoptotic cell death. Moreover, Paip1 depletion upregulates the transcription factor gene Xrp1, which contributes to apoptotic cell death and eIF2α phosphorylation. We further show that loss of Paip1 leads to an increase in Xrp1 translation mediated by its 5'UTR. These findings uncover a novel mechanism that links translation impairment to tissue homeostasis and establish a role of ISR activation and Xrp1 in promoting cell death.

14.
J Mol Cell Biol ; 2023 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-38059855

RESUMO

Mutations or dysregulated expression of NF-kappaB activating protein (NKAP) family genes have been found in human cancers. How NKAP family gene mutations promote tumor initiation and progression remains to be determined. Here, we characterized dNKAP, the Drosophila homolog of NKAP, and showed that impaired dNKAP function causes genome instability and tumorigenic growth in a Drosophila epithelial tumor model. dNKAP-knockdown wing imaginal discs exhibit tumorigenic characteristics, including tissue overgrowth, cell invasive behavior, abnormal cell polarity, and cell adhesion defects. dNKAP knockdown causes both R-loop accumulation and DNA damage, indicating the disruption of genome integrity. Further analysis showed that dNKAP knockdown induces c-Jun N-terminal kinase (JNK)-dependent apoptosis and causes changes in cell proliferation in distinct cell populations. Activation of the Notch and JAK/STAT signaling pathways contributes to the tumorigenic growth of dNKAP-knockdown tissues. Furthermore, JNK signaling is essential for dNKAP depletion-mediated cell invasion. Transcriptome analysis of dNKAP-knockdown tissues confirmed the misregulation of signaling pathways involved in promoting tumorigenesis and revealed abnormal regulation of metabolic pathways. dNKAP knockdown and oncogenic Ras, Notch, or Yki mutations show synergies in driving tumorigenesis, further supporting the tumor-suppressive role of dNKAP. In summary, this study demonstrates that dNKAP plays a tumor-suppressive role by preventing genome instability in Drosophila epithelia and thus provides novel insights into the roles of human NKAP family genes in tumor initiation and progression.

15.
Dev Cell ; 12(6): 987-96, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17543869

RESUMO

Correct positioning of the cell-division plane is crucial for cell function in all organisms. The fission yeast Schizosaccharomyces pombe divides by utilizing an actomyosin-based contractile ring and is an attractive model for the study of cytokinesis. The metazoan anillin-related protein Mid1p stimulates medial assembly of the division septum by recruiting actomyosin-ring components to the medial cortex. Here, we describe an inhibitory mechanism, involving the cell-end-localized polarity determinants Tea1p, Tea4p/Wsh3p, and Pom1p (tip complex), which prevents division-septum assembly at the cell ends. While Mid1p and the tip complex are dispensable for cell viability, their simultaneous loss leads to lethality. The FER/CIP homology protein Cdc15p, which organizes the actomyosin ring and cell membranes during cytokinesis, is a candidate for regulation by the tip complex. Since dual regulation of division-site placement is also seen in nematodes, such regulation might be a general feature of eukaryotic cytokinesis.


Assuntos
Polaridade Celular , Citocinese , Proteínas Associadas aos Microtúbulos/metabolismo , Proteínas Quinases/metabolismo , Proteínas de Schizosaccharomyces pombe/metabolismo , Schizosaccharomyces/metabolismo , Actomiosina/metabolismo , Proteínas de Ciclo Celular/metabolismo , Divisão Celular , Proteínas de Ligação ao GTP/metabolismo , Proteínas de Choque Térmico/metabolismo , Proteínas de Filamentos Intermediários/metabolismo , Schizosaccharomyces/crescimento & desenvolvimento
16.
J Ovarian Res ; 15(1): 48, 2022 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-35477477

RESUMO

BACKGROUND: Taxol resistance in serous ovarian cancer is responsible for its poor prognosis, yet the underlying mechanism is still poorly understood. Thus, we probed the mechanism of Taxol resistance in serous ovarian cancer with multiple bioinformatic methods to provide novel insights into potential therapies. METHODS: The differentially expressed genes (DEGs) in Taxol-sensitive and Taxol-resistant cell lines and their relationship with the overall survival (OS) and progression-free interval (PFI) of ovarian cancer patients were analyzed using gene expression datasets from the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO). The role of receptor interacting serine/threonine kinase 2 (RIPK2) was validated via identification of its coexpressed genes, functional analysis and generation of a protein-protein interaction (PPI) network. The single sample gene set enrichment analysis (ssGSEA) was used to explore immune infiltration, and genomic alterations of RIPK2 were also analyzed via cBio Cancer Genomics Portal (cBioProtal). RESULTS: RIPK2 was highly expressed in Taxol resistant ovarian cancer cell lines, and its high expression was also linked with shorter OS and PFI in serous ovarian cancer patients. The PPI network analysis and pathway analysis demonstrated that RIPK2 might participate in the positive regulation of NF-κB transcription factor activity. RIPK2 expression was related to tumor microenvironment alterations, which might participate in the formation of Taxol resistance. CONCLUSIONS: Our studies suggested that high expression of RIPK2 is related to Taxol resistance in serous ovarian cancer, and that RIPK2 induces Taxol resistance through NOD1/RIPK2/NF-κB inflammatory pathway activation and tumor microenvironment changes.


Assuntos
Cistadenocarcinoma Seroso , Neoplasias Ovarianas , Carcinoma Epitelial do Ovário , Cistadenocarcinoma Seroso/tratamento farmacológico , Cistadenocarcinoma Seroso/genética , Cistadenocarcinoma Seroso/patologia , Feminino , Humanos , NF-kappa B/metabolismo , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/metabolismo , Paclitaxel/farmacologia , Paclitaxel/uso terapêutico , Proteína Serina-Treonina Quinase 2 de Interação com Receptor/genética , Proteína Serina-Treonina Quinase 2 de Interação com Receptor/metabolismo , Microambiente Tumoral/genética
17.
Cell Biosci ; 12(1): 78, 2022 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-35642004

RESUMO

BACKGROUND: Mental retardation is a complex neurodevelopmental disorder. NPAT, a component of the histone locus body (HLB), has been implicated as a candidate gene for mental retardation, with a mechanism yet to be elucidated. RESULTS: We identified that mxc, the Drosophila ortholog of NPAT, is required for the development of nervous system. Knockdown of mxc resulted in a massive loss of neurons and locomotion dysfunction in adult flies. In the mxc mutant or RNAi knockdown larval brains, the neuroblast (NB, also known as neural stem cell) cell fate is prematurely terminated and its proliferation potential is impeded concurrent with the blocking of the differentiation process of ganglion mother cells (GMCs). A reduction of transcription levels of histone genes was shown in mxc knockdown larval brains, accompanied by DNA double-strand breaks (DSBs). The subsidence of histone transcription levels leads to prematurely termination of NB cell fate and blockage of the GMC differentiation process. Our data also show that the increase in autophagy induced by mxc knockdown in NBs could be a defense mechanism in response to abnormal HLB assembly and premature termination of NB cell fate. CONCLUSIONS: Our study demonstrate that Mxc plays a critical role in maintaining neural stem cell fate and GMC differentiation in the Drosophila larval brain. This discovery may shed light on the understanding of the pathogenesis of NPAT-related mental retardation in humans.

18.
Nat Commun ; 13(1): 2484, 2022 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-35513466

RESUMO

m5C is one of the longest-known RNA modifications, however, its developmental dynamics, functions, and evolution in mRNAs remain largely unknown. Here, we generate quantitative mRNA m5C maps at different stages of development in 6 vertebrate and invertebrate species and find convergent and unexpected massive methylation of maternal mRNAs mediated by NSUN2 and NSUN6. Using Drosophila as a model, we reveal that embryos lacking maternal mRNA m5C undergo cell cycle delays and fail to timely initiate maternal-to-zygotic transition, implying the functional importance of maternal mRNA m5C. From invertebrates to the lineage leading to humans, two waves of m5C regulatory innovations are observed: higher animals gain cis-directed NSUN2-mediated m5C sites at the 5' end of the mRNAs, accompanied by the emergence of more structured 5'UTR regions; humans gain thousands of trans-directed NSUN6-mediated m5C sites enriched in genes regulating the mitotic cell cycle. Collectively, our studies highlight the existence and regulatory innovations of a mechanism of early embryonic development and provide key resources for elucidating the role of mRNA m5C in biology and disease.


Assuntos
RNA Mensageiro Estocado , Zigoto , Animais , Drosophila/genética , Desenvolvimento Embrionário/genética , Regulação da Expressão Gênica no Desenvolvimento , Metilação , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Mensageiro Estocado/genética , RNA Mensageiro Estocado/metabolismo , Zigoto/metabolismo
19.
J Ovarian Res ; 14(1): 38, 2021 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-33627162

RESUMO

OBJECTIVE: To investigate the detailed roles and mechanisms of tumor-derived exosomes in progression and metastasis of ovarian cancer in vitro. METHODS: Exosomes were isolated by differential centrifugation method; the morphology, size and biological markers of exosomes were separately defined by transmission electron microscopy, nanoS90 and Western blotting; Trans-well chambers assay was used to assess the ability of migration and invasion of recipient cells uptaking the exosomes from HO8910PM cells. The downstream molecule was screened by mass spectrometry.CD44 was identified by western blotting and the function of CD44 was identified by trans-well chambers assay and CCK8 assay. RESULTS: Exosomes derived from HO8910PM cells could be transferred to HO8910 cells and promote cell migration and invasion in the recipient cells of ovarian cancer. And CD44 could be transferred to the HO8910 cells through exosomes from HO8910PM cells and influence the migration and invasion ability of HO8910 cells. CONCLUSION: The more aggressive subpopulation can transfer a metastatic phenotype to the less one via secreting exosomes within a heterogeneous tumor. CD44 may be a potential therapeutic approach for ovarian cancer.


Assuntos
Carcinoma Epitelial do Ovário/genética , Movimento Celular/genética , Exossomos/metabolismo , Receptores de Hialuronatos/metabolismo , Neoplasias Ovarianas/genética , Carcinoma Epitelial do Ovário/metabolismo , Carcinoma Epitelial do Ovário/secundário , Linhagem Celular Tumoral , Feminino , Humanos , Receptores de Hialuronatos/genética , Espectrometria de Massas , Microscopia Eletrônica de Transmissão , Metástase Neoplásica/genética , Neoplasias Ovarianas/metabolismo , Neoplasias Ovarianas/patologia , Fenótipo
20.
Cell Death Differ ; 28(2): 764-779, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-32913227

RESUMO

Increasing evidence suggests that miRNAs play important regulatory roles in the nervous system. However, the molecular mechanisms of how specific miRNAs affect neuronal development and functions remain less well understood. In the present study, we provide evidence that the conserved microRNA miR-210 regulates lipid metabolism and prevents neurodegeneration in the Drosophila retina. miR-210 is specifically expressed in the photoreceptor neurons and other sensory organs. Genetic deletion of miR-210 leads to lipid droplet accumulation and photoreceptor degeneration in the retina. These effects are associated with abnormal activation of the Drosophila sterol regulatory element-binding protein signaling. We further identify the acetyl-coenzyme A synthetase (ACS) as one functionally important target of miR-210 in this context. Reduction of ACS in the miR-210 mutant background suppresses the neurodegeneration defects, suggesting that miR-210 acts through regulation of the ACS transcript. Together, these results reveal an unexpected role of miR-210 in controlling lipid metabolism and neuronal functions.


Assuntos
Drosophila melanogaster/genética , Metabolismo dos Lipídeos/genética , MicroRNAs/genética , Degeneração Retiniana/genética , Animais , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Homeostase , MicroRNAs/metabolismo , Neurogênese , Neurônios/metabolismo , Transdução de Sinais
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