Almost all organisms exhibit ~24-h rhythms, or circadian rhythms, in a plentitude of biological processes.These rhythms are driven by endogenous molecular clocks consisting of a series of transcriptional and translati...Almost all organisms exhibit ~24-h rhythms, or circadian rhythms, in a plentitude of biological processes.These rhythms are driven by endogenous molecular clocks consisting of a series of transcriptional and translational feedback loops. Previously, we have shown that the inner nuclear membrane protein MAN1 regulates this clock and thus the locomotor rhythm in flies, but the mechanism remains unclear. Here, we further confirmed the previous findings and found that knocking down MAN1 in the pacemaker neurons of adult flies is sufficient to lengthen the period of the locomotor rhythm. Molecular analysis revealed that knocking down MAN1 led to reduced m RNA and protein levels of the core clock gene period(per),likely by reducing its transcription. Over-expressing per rescued the long period phenotype caused by MAN1 deficiency whereas per mutation had an epistatic effect on MAN1, indicating that MAN1 sets the pace of the clock by targeting per.展开更多
The nuclear envelope(NE)is a dynamic,mechanosensitive structure that functions as a protective barrier for the genome and serves as a checkpoint responding to external stimuli.It plays a critical role in maintaining g...The nuclear envelope(NE)is a dynamic,mechanosensitive structure that functions as a protective barrier for the genome and serves as a checkpoint responding to external stimuli.It plays a critical role in maintaining genomic stability and regulating cell fate.This review synthesizes recent research highlighting the role of NE as a me-chanical checkpoint in ensuring accurate chromosome segregation,regulating cell cycle progression,and contributing to cancer development.Chromosome mis-segregation during cell division is a major driver of aneuploidy,a condition closely associated with genomic instability and cellular transformation.The role of NE in chromatin organization and gene expression regulation is also discussed,underscoring its importance in cell differentiation and identity.展开更多
Microtubules grow not only from the centrosome but also from various noncentrosomal microtubule-organizing centers(MTOCs),including the nuclear envelope(NE)and pre-existing microtubules.The evolutionarily conserved pr...Microtubules grow not only from the centrosome but also from various noncentrosomal microtubule-organizing centers(MTOCs),including the nuclear envelope(NE)and pre-existing microtubules.The evolutionarily conserved proteins Mtol/CDK5RAP2 and Alpl4/TOG/XMAP215 have been shown to be involved in promoting microtubule nucleation.However,it has remained elusive as to how the microtubule nucleation promoting factors are specified to various noncentrosomal MTOCs,particularly the NE,and how these proteins coordinate to organize microtubule assembly.Here,we demonstrate that in the fission yeast Schizosaccharomyces pombe,efficient interphase microtubule growth from the NE requires Alp7/TACC,Alpl4/TOG/XMAP215,and Mtol/CDK5RAP2.The absence of Alp7,A lp l4 t or Mtol compromises microtubule regrowth on the NE in cells undergoing microtubule repolymerization.We further demonstrate that Alp7 and Mtol interdependently localize to the NE in cells without microtubules and that A lp l4 localizes to the NE in an Alp7 and Mtol-dependent manner.Tethering Mtol to the NE in cells lacking Alp7 partially restores microtubule number and the efficiency of microtubule generation from the NE.Hence,our study delineates that Alp7,A lpl4,and Mtol work in concert to regulate interphase microtubule regrowth on the NE.展开更多
Taxanes,including paclitaxel,docetaxel,and cabazitaxel,are key agents in cancer treatment,often used as frontline chemotherapy drugs in combination with other agent(s)(commonly carboplatin)and as second-line treatment...Taxanes,including paclitaxel,docetaxel,and cabazitaxel,are key agents in cancer treatment,often used as frontline chemotherapy drugs in combination with other agent(s)(commonly carboplatin)and as second-line treatments alone.Generally,taxanes are highly effective,but drug resistance unavoidably develops following repeated treatment.Taxanes work by binding to and stabilizing microtubules,leading to mitotic arrest,mitotic catastrophe,and micronucleation.The long-recognized mechanisms of drug resistance generally can be classified into three categories:drug efflux,microtubule polymerization,and apoptotic pathway.A recent new addition to this list is a mechanism related to the nuclear envelope,as cancer cells undergo micronucleation and nuclear membrane rupture when treated with taxanes.All these mechanismsmay operate simultaneously as taxane resistance is multi-factorial.Here,we review the cell biology understanding of nuclear envelope breaking in production of micronucleation,and nuclear membrane rupture and repair,and propose that these processes are involved in taxane resistance.展开更多
The link of the metazoan nucleus to the actin cytoskeleton is highly important for actin polymerization and migration of multiple cell types as well as for mechanotransduction and even affects the cellular transcripto...The link of the metazoan nucleus to the actin cytoskeleton is highly important for actin polymerization and migration of multiple cell types as well as for mechanotransduction and even affects the cellular transcriptome.Several mechanisms of organization of actin filaments next to the nuclear envelope have been identified.Among these mechanisms the most studied one is the Linker of nucleoskeleton and cytoskeleton(LINC)complex-dependent perinuclear actin organization.However,recently additional mechanisms have been identified:an Actin-related protein-2/3(Arp2/3)-dependent perinuclear actin polymerization during migration of dendritic cells and a perinuclear actin rim that is formed in response to external force application or migration cues.In parallel,there are also reports on cancer cells that migrate in a LINC complex independent manner and on cancers with reduced expression of the LINC complex components.Thus,suggesting that LINC complex independent migration may be associated with tumour formation.展开更多
AIM: To study the mechanism underlying carbon tetrachloride (CCl4)-induced alterations of protein synthesis in liver. METHODS: Male Sprague-Dawley rats were given CCl4 (1 mL/100 g body weight) and 3H-leucine incorpora...AIM: To study the mechanism underlying carbon tetrachloride (CCl4)-induced alterations of protein synthesis in liver. METHODS: Male Sprague-Dawley rats were given CCl4 (1 mL/100 g body weight) and 3H-leucine incorporation. Malondialdehyde (MDA) level in the liver, in vitro response of hepatocyte nuclei nucleotide triphosphatase (NTPase) to free radicals, and nuclear export of total mRNA with 3'-poly A+ were measured respectively. Survival response of HepG2 cells to CCl4 treatment was assessed by methyl thiazolyl tetrazolium. Km and Vmax values of nuclear envelope NTPase activity in liver of rats treated with CCl4 were assayed by a double-reciprocal plot. RESULTS: The protein synthesis was inhibited while the MDA level was signif icantly increased in liver of rats treated with CCl4. In addition, CCl4 decreased the NTPase binding capacity of nuclear envelope (Km value) in cultured HepG2 cells. Moreover, in vitro ferrous radicals from Fenton's system suppressed the NTPase activity of liver nuclear envelope in a dose-dependent manner. Down-regulation of the nuclear envelope NTPase activity indicated a lower energy provision for nucleocytoplasmic transport of mRNA molecules, an evidence in CCl4-treated HepG2 cells correspondingly supported by the nuclear sequestration of poly (A)+ mRNA molecules in morphological hybridization research. CONCLUSION: Inhibition of mRNA transport, suggestive of decreased NTPase activity of the nuclear envelope, may be involved in carbon tetrachloride-inhibited protein synthesis in liver.展开更多
The three-dimensional organization of the genome is closely related to its functioning. Interactions between parts of the genome located at large distances from each other have been detected within the chromosomes of ...The three-dimensional organization of the genome is closely related to its functioning. Interactions between parts of the genome located at large distances from each other have been detected within the chromosomes of different organisms, which led to the discovery of topologically associated domains (TADs). Methods that reveal such interactions between chromosomal loci imply detection of both protein-protein and protein-DNA interactions. We investigated the possibility of involvement of the direct DNA-DNA interactions in the structural and functional organization of Drosophila melanogaster chromosomal 87A7 locus, containing genes hsp70Aa and hsp70Ab, with the sequence analysis method. Our results indicate that the functional organization of 87A7 locus may involve different elements: chromosomal DNA fragments that attach chromosomes to the nuclear envelope, short polypurine/polypyrimidine tracts, insulators and their proteins. The combination of interactions of these elements may cause different functional states of 87A7 locus.展开更多
The endoplasmic reticulum(ER),which is composed of a continuous network of tubules and sheets,forms the most widely distributed membrane system in eukaryotic cells.As a result,it engages a variety of organelles by est...The endoplasmic reticulum(ER),which is composed of a continuous network of tubules and sheets,forms the most widely distributed membrane system in eukaryotic cells.As a result,it engages a variety of organelles by establishing membrane contact sites(MCSs).These contacts regulate organelle positioning and remodeling,including fusion and fission,facilitate precise lipid exchange,and couple vital signaling events.Here,we systematically review recent advances and converging themes on ER-involved organellar contact.The molecular basis,cellular influence,and potential physiological functions for ER/nuclear envelope contacts with mitochondria,Golgi,endosomes,lysosomes,lipid droplets,autophagosomes,and plasma membrane are summarized.展开更多
Bidirectional trafficking of macromolecules between the cytoplasm and the nucleus is mediated by the nuclear pore complexes(NPCs)embedded in the nuclear envelope(NE)of eukaryotic cell.The NPC functions as the sole pat...Bidirectional trafficking of macromolecules between the cytoplasm and the nucleus is mediated by the nuclear pore complexes(NPCs)embedded in the nuclear envelope(NE)of eukaryotic cell.The NPC functions as the sole pathway to allow for the passive diffusion of small molecules and the facilitated translocation of larger molecules.Evidence shows that these two transport modes and the conformation of NPC can be regulated by calcium stored in the lumen of nuclear envelope and endoplasmic reticulum.However,the mechanism of calcium regulation remains poorly understood.In this review,we integrate data on the observations of calciumregulated structure and function of the NPC over the past years.Furthermore,we highlight challenges in the measurements of dynamic conformational changes and transient transport kinetics in the NPC.Finally,an innovative imaging approach,single-molecule superresolution fluorescence microscopy,is introduced and expected to provide more insights into the mechanism of calcium-regulated nucleocytoplasmic transport.展开更多
Super-resolution imaging techniques have broken the diffraction-limited resolution of light microscopy.However,acquiring three-dimensional(3D)super-resolution information about structures and dynamic processes in live...Super-resolution imaging techniques have broken the diffraction-limited resolution of light microscopy.However,acquiring three-dimensional(3D)super-resolution information about structures and dynamic processes in live cells at high speed remains challenging.Recently,the development of high-speed single-point edge-excitation subdiffraction(SPEED)microscopy,along with its 2D-to-3D transformation algorithm,provides a practical and effective approach to achieving 3D subdiffraction-limit information in subcellular structures and organelles with rotational symmetry.One of the major benefits of SPEED microscopy is that it does not rely on complex optical components and can be implemented on a standard,inverted epifluorescence microscope,simplifying the process of sample preparation and the expertise requirement.SPEED microscopy is specifically designed to obtain 2D spatial locations of individual immobile or moving fluorescent molecules inside submicrometer biological channels or cavities at high spatiotemporal resolution.The collected data are then subjected to postlocalization 2D-to-3D transformation to obtain 3D super-resolution structural and dynamic information.In recent years,SPEED microscopy has provided significant insights into nucleocytoplasmic transport across the nuclear pore complex(NPC)and cytoplasm-cilium trafficking through the ciliary transition zone.This Review focuses on the applications of SPEED microscopy in studying the structure and function of nuclear pores.展开更多
基金supported by grants from the National Natural Science Foundation of China (31471125 and 31671215)‘‘1000 Talents’’ Program of China
文摘Almost all organisms exhibit ~24-h rhythms, or circadian rhythms, in a plentitude of biological processes.These rhythms are driven by endogenous molecular clocks consisting of a series of transcriptional and translational feedback loops. Previously, we have shown that the inner nuclear membrane protein MAN1 regulates this clock and thus the locomotor rhythm in flies, but the mechanism remains unclear. Here, we further confirmed the previous findings and found that knocking down MAN1 in the pacemaker neurons of adult flies is sufficient to lengthen the period of the locomotor rhythm. Molecular analysis revealed that knocking down MAN1 led to reduced m RNA and protein levels of the core clock gene period(per),likely by reducing its transcription. Over-expressing per rescued the long period phenotype caused by MAN1 deficiency whereas per mutation had an epistatic effect on MAN1, indicating that MAN1 sets the pace of the clock by targeting per.
基金supported by the National Natural Science Foundation of China(grants 12422212,11902121,and 32071306 to JC,11902122 to FW)the Fundamental Research Funds for the Central Universities(2024BRB004 to JC)the Huazhong University of Science and Technology Program for Academic Frontier Youth Team(2018QYTD01 to JC).
文摘The nuclear envelope(NE)is a dynamic,mechanosensitive structure that functions as a protective barrier for the genome and serves as a checkpoint responding to external stimuli.It plays a critical role in maintaining genomic stability and regulating cell fate.This review synthesizes recent research highlighting the role of NE as a me-chanical checkpoint in ensuring accurate chromosome segregation,regulating cell cycle progression,and contributing to cancer development.Chromosome mis-segregation during cell division is a major driver of aneuploidy,a condition closely associated with genomic instability and cellular transformation.The role of NE in chromatin organization and gene expression regulation is also discussed,underscoring its importance in cell differentiation and identity.
基金the National Key Research and Development Program of China(2017YFA0503600)the National Natural Science Foundation of China(91754106,31871350,31671406,31601095,and 31621002)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB19040101)the Major/lnnovative Program of Development Foundation of Hefei Center for Physical Science and Technology(2017FXCX008)China’s 1000 Young Talents Recruitment Program.
文摘Microtubules grow not only from the centrosome but also from various noncentrosomal microtubule-organizing centers(MTOCs),including the nuclear envelope(NE)and pre-existing microtubules.The evolutionarily conserved proteins Mtol/CDK5RAP2 and Alpl4/TOG/XMAP215 have been shown to be involved in promoting microtubule nucleation.However,it has remained elusive as to how the microtubule nucleation promoting factors are specified to various noncentrosomal MTOCs,particularly the NE,and how these proteins coordinate to organize microtubule assembly.Here,we demonstrate that in the fission yeast Schizosaccharomyces pombe,efficient interphase microtubule growth from the NE requires Alp7/TACC,Alpl4/TOG/XMAP215,and Mtol/CDK5RAP2.The absence of Alp7,A lp l4 t or Mtol compromises microtubule regrowth on the NE in cells undergoing microtubule repolymerization.We further demonstrate that Alp7 and Mtol interdependently localize to the NE in cells without microtubules and that A lp l4 localizes to the NE in an Alp7 and Mtol-dependent manner.Tethering Mtol to the NE in cells lacking Alp7 partially restores microtubule number and the efficiency of microtubule generation from the NE.Hence,our study delineates that Alp7,A lpl4,and Mtol work in concert to regulate interphase microtubule regrowth on the NE.
基金partially supported by NIH funding R01 CA095071,CA79716,and CA75389 to XX from NCI,NIHseed funding from Sylvester Comprehensive Cancer Center,University of Miami.
文摘Taxanes,including paclitaxel,docetaxel,and cabazitaxel,are key agents in cancer treatment,often used as frontline chemotherapy drugs in combination with other agent(s)(commonly carboplatin)and as second-line treatments alone.Generally,taxanes are highly effective,but drug resistance unavoidably develops following repeated treatment.Taxanes work by binding to and stabilizing microtubules,leading to mitotic arrest,mitotic catastrophe,and micronucleation.The long-recognized mechanisms of drug resistance generally can be classified into three categories:drug efflux,microtubule polymerization,and apoptotic pathway.A recent new addition to this list is a mechanism related to the nuclear envelope,as cancer cells undergo micronucleation and nuclear membrane rupture when treated with taxanes.All these mechanismsmay operate simultaneously as taxane resistance is multi-factorial.Here,we review the cell biology understanding of nuclear envelope breaking in production of micronucleation,and nuclear membrane rupture and repair,and propose that these processes are involved in taxane resistance.
基金This research was funded by the Israel Cancer Association,Grant No.20190028 and Ariel University.
文摘The link of the metazoan nucleus to the actin cytoskeleton is highly important for actin polymerization and migration of multiple cell types as well as for mechanotransduction and even affects the cellular transcriptome.Several mechanisms of organization of actin filaments next to the nuclear envelope have been identified.Among these mechanisms the most studied one is the Linker of nucleoskeleton and cytoskeleton(LINC)complex-dependent perinuclear actin organization.However,recently additional mechanisms have been identified:an Actin-related protein-2/3(Arp2/3)-dependent perinuclear actin polymerization during migration of dendritic cells and a perinuclear actin rim that is formed in response to external force application or migration cues.In parallel,there are also reports on cancer cells that migrate in a LINC complex independent manner and on cancers with reduced expression of the LINC complex components.Thus,suggesting that LINC complex independent migration may be associated with tumour formation.
基金Supported by The National Natural Science Foundation of China,No.30470846
文摘AIM: To study the mechanism underlying carbon tetrachloride (CCl4)-induced alterations of protein synthesis in liver. METHODS: Male Sprague-Dawley rats were given CCl4 (1 mL/100 g body weight) and 3H-leucine incorporation. Malondialdehyde (MDA) level in the liver, in vitro response of hepatocyte nuclei nucleotide triphosphatase (NTPase) to free radicals, and nuclear export of total mRNA with 3'-poly A+ were measured respectively. Survival response of HepG2 cells to CCl4 treatment was assessed by methyl thiazolyl tetrazolium. Km and Vmax values of nuclear envelope NTPase activity in liver of rats treated with CCl4 were assayed by a double-reciprocal plot. RESULTS: The protein synthesis was inhibited while the MDA level was signif icantly increased in liver of rats treated with CCl4. In addition, CCl4 decreased the NTPase binding capacity of nuclear envelope (Km value) in cultured HepG2 cells. Moreover, in vitro ferrous radicals from Fenton's system suppressed the NTPase activity of liver nuclear envelope in a dose-dependent manner. Down-regulation of the nuclear envelope NTPase activity indicated a lower energy provision for nucleocytoplasmic transport of mRNA molecules, an evidence in CCl4-treated HepG2 cells correspondingly supported by the nuclear sequestration of poly (A)+ mRNA molecules in morphological hybridization research. CONCLUSION: Inhibition of mRNA transport, suggestive of decreased NTPase activity of the nuclear envelope, may be involved in carbon tetrachloride-inhibited protein synthesis in liver.
文摘The three-dimensional organization of the genome is closely related to its functioning. Interactions between parts of the genome located at large distances from each other have been detected within the chromosomes of different organisms, which led to the discovery of topologically associated domains (TADs). Methods that reveal such interactions between chromosomal loci imply detection of both protein-protein and protein-DNA interactions. We investigated the possibility of involvement of the direct DNA-DNA interactions in the structural and functional organization of Drosophila melanogaster chromosomal 87A7 locus, containing genes hsp70Aa and hsp70Ab, with the sequence analysis method. Our results indicate that the functional organization of 87A7 locus may involve different elements: chromosomal DNA fragments that attach chromosomes to the nuclear envelope, short polypurine/polypyrimidine tracts, insulators and their proteins. The combination of interactions of these elements may cause different functional states of 87A7 locus.
基金supported by the National Natural Science Foundation of China(92254305)supported by the National Natural Science Foundation of China(92254305,91854204,32130026)+20 种基金supported by National Natural Science Foundation of China(92254302,32225013,32130023)supported by the National Natural Science Foundation of China(91954201,31971289)supported by grants from the National Natural Science Foundation of China(91954207)supported by the National Natural Science Foundation of China(32170753)supported by the National Natural Science Foundation of China(32170692,92154001)supported by grants from the National Natural Science Foundation of China(92254303,32170701)supported by grants from the National Natural Science Foundation of China(32101000,32271273)the Strategic Priority Research Program(XDB39000000)Project for Young Scientists in Basic Research(YSBR-075)of the Chinese Academy of Sciencesthe National Key Research and Development Program of China(2021YFA1300800)National Key Research and Development Program of China(2021YFA0804802,2019YFA0508602)Beijing Natural Science Foundation(JQ20028)New Cornerstone Science Foundation(Xplorer Prize)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB37020304)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB37040402)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA24030205)the National Key Research and Development Program of China(2021YFA1300301)the National Key Research and Development Program of China(2018YFA0506902)the Fundamental Research Funds for the Central Universities(63213104,63223043)the Talent Training Project at Nankai University(035-BB042112)supported by the Beijing Municipal Science&Technology Commission(5202022)。
文摘The endoplasmic reticulum(ER),which is composed of a continuous network of tubules and sheets,forms the most widely distributed membrane system in eukaryotic cells.As a result,it engages a variety of organelles by establishing membrane contact sites(MCSs).These contacts regulate organelle positioning and remodeling,including fusion and fission,facilitate precise lipid exchange,and couple vital signaling events.Here,we systematically review recent advances and converging themes on ER-involved organellar contact.The molecular basis,cellular influence,and potential physiological functions for ER/nuclear envelope contacts with mitochondria,Golgi,endosomes,lysosomes,lipid droplets,autophagosomes,and plasma membrane are summarized.
基金We thank the grant support from National Institutes of Health(GM094041-01)the Research Capacity Enhancement Grant(Bowling Green State University).
文摘Bidirectional trafficking of macromolecules between the cytoplasm and the nucleus is mediated by the nuclear pore complexes(NPCs)embedded in the nuclear envelope(NE)of eukaryotic cell.The NPC functions as the sole pathway to allow for the passive diffusion of small molecules and the facilitated translocation of larger molecules.Evidence shows that these two transport modes and the conformation of NPC can be regulated by calcium stored in the lumen of nuclear envelope and endoplasmic reticulum.However,the mechanism of calcium regulation remains poorly understood.In this review,we integrate data on the observations of calciumregulated structure and function of the NPC over the past years.Furthermore,we highlight challenges in the measurements of dynamic conformational changes and transient transport kinetics in the NPC.Finally,an innovative imaging approach,single-molecule superresolution fluorescence microscopy,is introduced and expected to provide more insights into the mechanism of calcium-regulated nucleocytoplasmic transport.
基金supported by grants from the US NIH(NIH GM097037,GM116204 and GM122552 to W.Y.).
文摘Super-resolution imaging techniques have broken the diffraction-limited resolution of light microscopy.However,acquiring three-dimensional(3D)super-resolution information about structures and dynamic processes in live cells at high speed remains challenging.Recently,the development of high-speed single-point edge-excitation subdiffraction(SPEED)microscopy,along with its 2D-to-3D transformation algorithm,provides a practical and effective approach to achieving 3D subdiffraction-limit information in subcellular structures and organelles with rotational symmetry.One of the major benefits of SPEED microscopy is that it does not rely on complex optical components and can be implemented on a standard,inverted epifluorescence microscope,simplifying the process of sample preparation and the expertise requirement.SPEED microscopy is specifically designed to obtain 2D spatial locations of individual immobile or moving fluorescent molecules inside submicrometer biological channels or cavities at high spatiotemporal resolution.The collected data are then subjected to postlocalization 2D-to-3D transformation to obtain 3D super-resolution structural and dynamic information.In recent years,SPEED microscopy has provided significant insights into nucleocytoplasmic transport across the nuclear pore complex(NPC)and cytoplasm-cilium trafficking through the ciliary transition zone.This Review focuses on the applications of SPEED microscopy in studying the structure and function of nuclear pores.
