Biochimica et Biophysica Acta-Gene Regulatory Mechanisms最新文献

{"title":"Influence of cell volume on the gene transcription rate","authors":"José E. Pérez-Ortín ,&nbsp;María J. García-Marcelo ,&nbsp;Irene Delgado-Román ,&nbsp;María C. Muñoz-Centeno ,&nbsp;Sebastián Chávez","doi":"10.1016/j.bbagrm.2024.195008","DOIUrl":"10.1016/j.bbagrm.2024.195008","url":null,"abstract":"<div><p><span>Cells vary in volume throughout their life cycle and in many other circumstances, while their genome remains identical. Hence, the RNA production factory must adapt to changing needs, while maintaining the same production lines. This paradox is resolved by different mechanisms in distinct cells and circumstances. RNA polymerases have evolved to cope with the particular circumstances of each case and the different characteristics of the several RNA molecule types, especially their stabilities. Here we review current knowledge on these issues. We focus on the yeast </span><span><em>Saccharomyces cerevisiae</em></span>, where many of the studies have been performed, although we compare and discuss the results obtained in other eukaryotes and propose several ideas and questions to be tested and solved in the future.</p></div><div><h3>Take away</h3><p></p><ul><li><span>−</span><span><p>The mRNA synthesis rate can be influenced by cell volume, and vice versa</p></span></li><li><span>−</span><span><p>Transcription and degradation rates must compensate reciprocally to maintain RNA homeostasis</p></span></li><li><span>−</span><span><p>Different cells and RNAs with diverse stabilities use distinct regulatory mechanisms</p></span></li><li><span>−</span><span><p>Asymmetrical division requires alternative transcription rate regulation with volume</p></span></li></ul></div>","PeriodicalId":55382,"journal":{"name":"Biochimica et Biophysica Acta-Gene Regulatory Mechanisms","volume":"1867 1","pages":"Article 195008"},"PeriodicalIF":4.7,"publicationDate":"2024-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139514307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Post-translational regulation of the mTORC1 pathway: A switch that regulates metabolism-related gene expression","authors":"Yitao Wang ,&nbsp;Tobias Engel ,&nbsp;Xinchen Teng","doi":"10.1016/j.bbagrm.2024.195005","DOIUrl":"10.1016/j.bbagrm.2024.195005","url":null,"abstract":"<div><p><span><span><span><span>The mechanistic target of rapamycin complex 1 (mTORC1) is a kinase complex that plays a crucial role in coordinating cell growth in response to various signals, including </span>amino acids, growth factors, oxygen, and ATP. Activation of mTORC1 promotes cell growth and </span>anabolism, while its suppression leads to catabolism and inhibition of cell growth, enabling cells to withstand nutrient scarcity and stress. Dysregulation of mTORC1 activity is associated with numerous diseases, such as cancer, </span>metabolic disorders<span>, and neurodegenerative conditions. This review focuses on how post-translational modifications, particularly phosphorylation and ubiquitination, modulate mTORC1 </span></span>signaling pathway and their consequential implications for pathogenesis. Understanding the impact of phosphorylation and ubiquitination on the mTORC1 signaling pathway provides valuable insights into the regulation of cellular growth and potential therapeutic targets for related diseases.</p></div>","PeriodicalId":55382,"journal":{"name":"Biochimica et Biophysica Acta-Gene Regulatory Mechanisms","volume":"1867 1","pages":"Article 195005"},"PeriodicalIF":4.7,"publicationDate":"2024-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139500071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Targeting ‘histone mark’: Advanced approaches in epigenetic regulation of telomere dynamics in cancer","authors":"Ankita Das ,&nbsp;Ashok K. Giri ,&nbsp;Pritha Bhattacharjee","doi":"10.1016/j.bbagrm.2024.195007","DOIUrl":"10.1016/j.bbagrm.2024.195007","url":null,"abstract":"<div><p><span><span>Telomere integrity is required for the maintenance of </span>genome stability<span> and prevention of oncogenic transformation of cells. Recent evidence suggests the presence of epigenetic modifications<span> as an important regulator of mammalian telomeres. Telomeric and subtelomeric regions are rich in epigenetic marks that regulate </span></span></span>telomere length<span><span> majorly through DNA methylation and post-translational histone modifications. Specific </span>histone modifying enzymes<span><span> play an integral role in establishing telomeric histone codes<span> necessary for the maintenance of structural integrity. Alterations of crucial histone moieties and histone modifiers cause deregulations in the telomeric chromatin leading to carcinogenic manifestations. This review delves into the significance of histone modifications and their influence on telomere dynamics concerning cancer. Additionally, it highlights the existing research gaps that hold the potential to drive the development of therapeutic interventions targeting the telomere </span></span>epigenome.</span></span></p></div>","PeriodicalId":55382,"journal":{"name":"Biochimica et Biophysica Acta-Gene Regulatory Mechanisms","volume":"1867 1","pages":"Article 195007"},"PeriodicalIF":4.7,"publicationDate":"2024-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139492283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prospects and challenges of noncoding-RNA-mediated inhibition of heat shock protein 90 for cancer therapy","authors":"Shria Mattoo ,&nbsp;Abha Gupta ,&nbsp;Manvee Chauhan ,&nbsp;Akshi Agrawal ,&nbsp;Subrata Kumar Pore","doi":"10.1016/j.bbagrm.2024.195006","DOIUrl":"10.1016/j.bbagrm.2024.195006","url":null,"abstract":"<div><p><span><span>Heat Shock Protein 90 (HSP90) is a potential drug target for cancer therapy as it is often dysregulated in several cancers, including lung, breast, pancreatic, and prostate cancers. In cancer, HSP90 fails to maintain the structural and functional integrity of its several client proteins which are involved in the hallmarks of cancer such as </span>cell proliferation<span><span>, invasion, migration, angiogenesis, and apoptosis. Several </span>small molecule<span><span> inhibitors of HSP90 have been shown to exhibit anticancer effects in vitro and in vivo </span>animal models. However, a few of them are currently under clinical studies. The status and potential limitations of these inhibitors are discussed here. Studies demonstrate that several noncoding </span></span></span>RNAs<span> (ncRNAs) such as microRNAs<span> (miRNAs) and long noncoding RNAs<span> (lncRNAs) regulate HSP90 and its client proteins to modulate cellular processes to exhibit oncogenic or tumor suppressing properties. Over the last decade, miRNAs and lncRNAs have drawn significant interest from the scientific community as therapeutic agents or targets for clinical applications. Here, we discuss the detailed mechanistic regulation of HSP90 and its client proteins by ncRNAs. Moreover, we highlight the significance of these ncRNAs as potential therapeutic agents/targets, and the challenges associated with ncRNA-based therapies. This article aims to provide a holistic view on HSP90-regulating ncRNAs for the development of novel therapeutic strategies to combat cancer.</span></span></span></p></div>","PeriodicalId":55382,"journal":{"name":"Biochimica et Biophysica Acta-Gene Regulatory Mechanisms","volume":"1867 1","pages":"Article 195006"},"PeriodicalIF":4.7,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139465448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Insight into the mechanism of AML del(9q) progression: hnRNP K targets the myeloid master regulators CEBPA (C/EBPα) and SPI1 (PU.1)","authors":"Kerstin Rahn ,&nbsp;Ali T. Abdallah ,&nbsp;Lin Gan ,&nbsp;Shelley Herbrich ,&nbsp;Roland Sonntag ,&nbsp;Oscar Benitez ,&nbsp;Prerna Malaney ,&nbsp;Xiaorui Zhang ,&nbsp;Ashely G. Rodriguez ,&nbsp;Jared Brottem ,&nbsp;Gernot Marx ,&nbsp;Tim H. Brümmendorf ,&nbsp;Dirk H. Ostareck ,&nbsp;Antje Ostareck-Lederer ,&nbsp;Martina Crysandt ,&nbsp;Sean M. Post ,&nbsp;Isabel S. Naarmann-de Vries","doi":"10.1016/j.bbagrm.2023.195004","DOIUrl":"10.1016/j.bbagrm.2023.195004","url":null,"abstract":"<div><p><span>Deletions on the long arm of chromosome 9 (del(9q)) are recurrent abnormalities in about 2 % of acute myeloid leukemia cases, which usually involve </span><em>HNRNPK</em> and are frequently associated with other known aberrations. Based on an <em>Hnrnpk</em> haploinsufficient mouse model, a recent study demonstrated a function of hnRNP K in pathogenesis of myeloid malignancies <em>via</em><span><span> the regulation of cellular proliferation<span> and myeloid differentiation programs. Here, we provide evidence that reduced hnRNP K expression results in the dysregulated expression of C/EBPα and additional transcription factors. CyTOF analysis revealed monocytic skewing with increased levels of mature myeloid cells. To explore the role of hnRNP K during normal and pathological myeloid differentiation in humans, we characterized hnRNP K-interacting </span></span>RNAs<span> in human AML cell lines. Notably, RNA-sequencing revealed several mRNAs encoding key transcription factors involved in the regulation of myeloid differentiation as targets of hnRNP K. We showed that specific sequence motifs confer the interaction of </span></span><span><em>SPI1</em></span> and <span><em>CEBPA</em></span><span> 5′ and 3′UTRs with hnRNP K. The siRNA mediated reduction of hnRNP K in human AML cells resulted in an increase of PU.1 and C/EBPα that is most pronounced for the p30 isoform. The combinatorial treatment with the inducer of myeloid differentiation valproic acid resulted in increased C/EBPα expression and myeloid differentiation. Together, our results indicate that hnRNP K post-transcriptionally regulates the expression of myeloid master transcription factors. These novel findings can inaugurate novel options for targeted treatment of AML del(9q) by modulation of hnRNP K function.</span></p></div>","PeriodicalId":55382,"journal":{"name":"Biochimica et Biophysica Acta-Gene Regulatory Mechanisms","volume":"1867 1","pages":"Article 195004"},"PeriodicalIF":4.7,"publicationDate":"2023-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138441701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modulation of Krüppel-like factors (KLFs) interaction with their binding partners in cancers through acetylation and phosphorylation","authors":"Kanupriya Jha ,&nbsp;Amit Kumar ,&nbsp;Kartik Bhatnagar ,&nbsp;Anupam Patra ,&nbsp;Neel Sarovar Bhavesh ,&nbsp;Bipin Singh ,&nbsp;Sarika Chaudhary","doi":"10.1016/j.bbagrm.2023.195003","DOIUrl":"10.1016/j.bbagrm.2023.195003","url":null,"abstract":"<div><p><span>Post-translational modifications (PTMs) of transcription factors regulate transcriptional activity and play a key role in essentially all biological processes<span><span> and generate indispensable insight towards biological function including activity state, subcellular localization, protein solubility, protein folding, substrate trafficking, and protein-protein interactions. </span>Amino acids modified chemically via PTMs, function as molecular switches and affect the protein function and characterization and increase the </span></span>proteome<span><span> complexity. Krüppel-like transcription factors (KLFs) control essential cellular processes including proliferation, differentiation, migration, programmed cell death and various cancer-relevant processes. We investigated the interactions of KLF group-2 members with their binding partners to assess the role of acetylation and phosphorylation in KLFs on their </span>binding affinity. It was observed that acetylation and phosphorylation at different positions in KLFs have a variable effect on binding with specific partners. KLF2-EP300, KLF4-SP1, KLF6-ATF3, KLF6-JUN, and KLF7-JUN show stabilization upon acetylation or phosphorylation at variable positions. On the other hand, KLF4-CBP, KLF4-EP300, KLF5-CBP, KLF5-WWP1, KLF6-SP1, and KLF7-ATF3 show stabilization or destabilization due to acetylation or phosphorylation at variable positions in KLFs. This provides a molecular explanation of the experimentally observed dual role of KLF group-2 members as a suppressor or activator of cancers in a PTM-dependent manner.</span></p></div>","PeriodicalId":55382,"journal":{"name":"Biochimica et Biophysica Acta-Gene Regulatory Mechanisms","volume":"1867 1","pages":"Article 195003"},"PeriodicalIF":4.7,"publicationDate":"2023-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138296626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The association of the RSC remodeler complex with chromatin is influenced by the prefoldin-like Bud27 and determines nucleosome positioning and polyadenylation sites usage in Saccharomyces cerevisiae","authors":"Abel Cuevas-Bermúdez ,&nbsp;Verónica Martínez-Fernández ,&nbsp;Ana I. Garrido-Godino ,&nbsp;Antonio Jordán-Pla ,&nbsp;Xenia Peñate ,&nbsp;Manuel Martín-Expósito ,&nbsp;Gabriel Gutiérrez ,&nbsp;Chhabi K. Govind ,&nbsp;Sebastián Chávez ,&nbsp;Vicent Pelechano ,&nbsp;Francisco Navarro","doi":"10.1016/j.bbagrm.2023.194995","DOIUrl":"10.1016/j.bbagrm.2023.194995","url":null,"abstract":"<div><p><span>The tripartite interaction between the chromatin remodeler complex RSC, RNA<span><span> polymerase subunit Rpb5 and prefoldin-like Bud27 is necessary for proper RNA pol II elongation. Indeed lack of Bud27 alters this association and affects transcription elongation. This work investigates the consequences of lack of Bud27 on the chromatin association of RSC and RNA pol II, and on </span>nucleosome positioning. Our results demonstrate that RSC binds chromatin in gene bodies and lack of Bud27 alters this association, mainly around polyA sites. This alteration impacts chromatin organization and leads to the accumulation of RNA pol II molecules around polyA sites, likely due to pausing or arrest. Our data suggest that RSC is necessary to maintain chromatin organization around those sites, and any alteration of this organization results in the widespread use of alternative polyA sites. Finally, we also find a similar molecular phenotype that occurs upon TOR inhibition with rapamycin, which suggests that alternative </span></span>polyadenylation observed upon TOR inhibition is likely Bud27-dependent.</p></div>","PeriodicalId":55382,"journal":{"name":"Biochimica et Biophysica Acta-Gene Regulatory Mechanisms","volume":"1867 1","pages":"Article 194995"},"PeriodicalIF":4.7,"publicationDate":"2023-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134650487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A poly-histidine motif of HOXA1 is involved in regulatory interactions with cysteine-rich proteins","authors":"Damien Marchese,&nbsp;Florent Guislain,&nbsp;Tamara Pringels,&nbsp;Laure Bridoux,&nbsp;René Rezsohazy","doi":"10.1016/j.bbagrm.2023.194993","DOIUrl":"10.1016/j.bbagrm.2023.194993","url":null,"abstract":"<div><p><span>Homopolymeric amino acid repeats<span> are found in about 24 % of human proteins and are over-represented in transcriptions factors and kinases. Although relatively rare, homopolymeric histidine repeats (polyH) are more significantly found in proteins involved in the regulation of </span></span>embryonic development<span>. To gain a better understanding of the role of polyH in these proteins, we used a bioinformatic approach to search for shared features in the interactomes of polyH-containing proteins in human. Our analysis revealed that polyH protein interactomes are enriched in cysteine-rich proteins and in proteins containing (a) cysteine repeat(s). Focusing on HOXA1, a HOX transcription factor displaying one long polyH motif, we identified that the polyH motif is required for the HOXA1 interaction with such cysteine-rich proteins. We observed a correlation between the length of the polyH repeat and the strength of the HOXA1 interaction with one Cys-rich protein, MDFI. We also found that metal ion chelators disrupt the HOXA1-MDFI interaction supporting that such metal ions are required for the interaction. Furthermore, we identified three polyH interactors which down-regulate the transcriptional activity of HOXA1. Taken together, our data point towards the involvement of polyH and cysteines in regulatory interactions between proteins, notably transcription factors like HOXA1.</span></p></div>","PeriodicalId":55382,"journal":{"name":"Biochimica et Biophysica Acta-Gene Regulatory Mechanisms","volume":"1867 1","pages":"Article 194993"},"PeriodicalIF":4.7,"publicationDate":"2023-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89720656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Isolation and characterisation of promoters from mouse genome to drive post-meiotic germ cell-specific robust gene expression for functional genomics studies","authors":"Abhishek Das ,&nbsp;Srimoyee Koner ,&nbsp;Subeer S. Majumdar ,&nbsp;Nirmalya Ganguli","doi":"10.1016/j.bbagrm.2023.194994","DOIUrl":"10.1016/j.bbagrm.2023.194994","url":null,"abstract":"<div><p><span>The generation of spermatozoa from developing germ cells through mitotic and meiotic divisions is a highly regulated and complex process. Any defect in this process, may lead to subfertility/infertility. The role of different transcripts (mRNA/miRNA/lncRNA) in regulation of the pre-meiotic, meiotic, and post-meiotic stages of spermatogenesis<span> are being proposed based on various multiomics based approaches. Such differential gene-expression is regulated by promoter elements that are activated in a stage specific manner. To determine the role of these differentially expressed transcripts in the process of meiosis, a robust post-meiotic germ cell specific promoter is required. In the present study, we have isolated and characterized the expression of the mouse Proacrosin, SP10, and ELP<span> promoters for driving post-meiotic germ cell specific gene-expression. Promoter regions of all these 3 genes were isolated and cloned to generate mammalian expression vector. The transgene expression in post-meiotic germ cells was assessed in mice using the testicular electroporation method </span></span></span><em>in vitro</em> as well as <em>in vivo</em><span>, using above promoters. It was also validated in goat seminiferous tubules, </span><em>in vitro</em>. We have also carried out a comparative analysis of the strength of these promoters to confirm their robustness that indicated Proacrosin to be the most robust promoter that can be useful for diving post-meiotic germ cells specific gene-expression. These promoters can be used to alter gene-expression specifically in post-meiotic germ cells for deciphering the role(s) of germ cell genes in spermatogenic progression or for expressing various genome editing tools for engineering the germ cell genome to understand basis of subfertility/infertility.</p></div>","PeriodicalId":55382,"journal":{"name":"Biochimica et Biophysica Acta-Gene Regulatory Mechanisms","volume":"1867 1","pages":"Article 194994"},"PeriodicalIF":4.7,"publicationDate":"2023-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92157398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The functions of FOXP transcription factors and their regulation by post-translational modifications","authors":"Congwen Gao ,&nbsp;Honglin Zhu ,&nbsp;Peng Gong ,&nbsp;Chen Wu ,&nbsp;Xingzhi Xu ,&nbsp;Xuefei Zhu","doi":"10.1016/j.bbagrm.2023.194992","DOIUrl":"10.1016/j.bbagrm.2023.194992","url":null,"abstract":"<div><p><span><span>The forkhead box subfamily P (FOXP) of transcription factors, consisting of FOXP1, </span>FOXP2, </span>FOXP3<span><span>, and FOXP4, is involved in the regulation of multisystemic functioning. Disruption of the transcriptional activity of FOXP proteins leads to neurodevelopmental disorders and immunological diseases, as well as the suppression or promotion of carcinogenesis. The transcriptional activities of FOXP proteins are directly or indirectly regulated by diverse post-translational modifications, including phosphorylation, ubiquitination, </span>SUMOylation<span><span>, acetylation, O-GlcNAcylation, and </span>methylation. Here, we discuss how post-translational modifications modulate the multiple functions of FOXP proteins and examine the implications for tumorigenesis and cancer therapy.</span></span></p></div>","PeriodicalId":55382,"journal":{"name":"Biochimica et Biophysica Acta-Gene Regulatory Mechanisms","volume":"1866 4","pages":"Article 194992"},"PeriodicalIF":4.7,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41156288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}