By using the DNA specific cytochemical staining method (NAMA_Ur) and conventional electron microscopic technique, the authors examined the configuration of intranucleolar DNA in Allium cepa L. cells and found that...By using the DNA specific cytochemical staining method (NAMA_Ur) and conventional electron microscopic technique, the authors examined the configuration of intranucleolar DNA in Allium cepa L. cells and found that nucleolar DNA within the fibrillar center (FC) underwent a structural transformation process from condensed to extended state. The authors' observations also displayed a continuous arrangement process of nucleolar DNA, i.e., the extranucleolar DNA entered FC through the nucleolar organizer region (NOR) channel, then extended to the periphery of FC or to the border between FC and dense fibrillar component (DFC), and distributed along the periphery of FC. Thence, by passing through the NOR channel between FCs, the nucleolar DNA continued to transfer to other FCs and arranged in the same above_mentioned forms.展开更多
The effects of different concentrations of cadmium chloride ranging from 0.5 to 20 ppm on the nucleolus in root tip cells of Allium cepa were studied using the silver staining technique. The results indicated that aft...The effects of different concentrations of cadmium chloride ranging from 0.5 to 20 ppm on the nucleolus in root tip cells of Allium cepa were studied using the silver staining technique. The results indicated that after the treatment with Cd￣(2+),different changes in nucleolar morphology appeared. The nucleolar material was extruded from the nucleus into the cytoplasm,and the nucleoli at mitotic metaphase did not disappear. Apparently,cadmium showed a specific effects on the nucleoli in root tip cells of Allium cepa. The possible mechanism behind this phenomenon is also briefly discussed.展开更多
Processing of pre-rRNA is one of the major events taking place In the nucleolus. U3 snoRNA, an rRNA spliceosomal factor, is suggested to be essential in the first cleavage step of the 5' ETS sequence in the proces...Processing of pre-rRNA is one of the major events taking place In the nucleolus. U3 snoRNA, an rRNA spliceosomal factor, is suggested to be essential in the first cleavage step of the 5' ETS sequence in the processing of pre-rRNA. Identification of U3 in the nucleolus provides a piece of indirect evidence for pre-rRNA processing site and transportation of processing products. In the present study, subnucleolar distribution of U3 snoRNA in the nucleolus of Pisum sativum L. was studied by in situ hybridization with a U3 snoRNA probe. The results showed that the U3 labeling signals were distributed throughout dense fibrillar components (DFCs) and granular components (GCs), while no signal was found in fibrillar centers (FCs). When treated with actinomycine D (AMD), the labeling signals were decreased. Along with the increase of the AMD treatment time, the labeling signals became fewer and they were found in the distal regions of DFC and GC. Our results indicated that pre-rRNA splicing took place in the regions of DFC and GC, and the transportation of pre-rRNA processing products was from the regions around FCs towards the distal regions.展开更多
The nucleolus is the most prominent compartment in the nucleus and known as the site for ribosome biogenesis in eucaryotes. In contrast, there is no such equivalent structure for ribosome synthesis in procaryotes. Thi...The nucleolus is the most prominent compartment in the nucleus and known as the site for ribosome biogenesis in eucaryotes. In contrast, there is no such equivalent structure for ribosome synthesis in procaryotes. This raises two concerns that how does the nucleolus evolve and that whether the nucleolus remains playing a single role in ribosome biogenesis along the evolution. Increasing data support new nucleolus functions, including signal recognition particle assembly, small RNA modification, telomerase maturation, cell-cycle and aging control, and cell stress sensor. Multiple functions of the nucleolus possibly result from the plurifunctionality of nucleolar proteins, such as nucleolin and Nopp 140. Proteomic analyses of human and Arabidopsis nucleolus lead a remarkable progress in understanding the evolution and new functions of nucleoli. In this review, we present a brief history of nucleolus research and new concepts and unresolved questions. Also, we introduce hepatitis D virus for studying the communication between the nucleolus and other subnuclear compartments, and Caenorhabditis elegans for the role of nucleolus in the development and the epistatic control of nucleologenesis.展开更多
The nucleolus,as the‘nucleus of the nucleus’,is a prominent subcellular organelle in a eukaryocyte.The nucleolus serves as the centre for ribosome biogenesis,as well as an important site for cell-cycle regulation,ce...The nucleolus,as the‘nucleus of the nucleus’,is a prominent subcellular organelle in a eukaryocyte.The nucleolus serves as the centre for ribosome biogenesis,as well as an important site for cell-cycle regulation,cellular senescence,and stress response.The protein composition of the nucleolus changes dynamically through protein turnover to meet the needs of cellular activities or stress responses.Recent studies have identified a nucleolus-localized protein degradation pathway in zebrafish and humans,namely the Def-CAPN3 pathway,which is essential to ribosome production and cell-cycle progression,by controlling the turnover of multiple substrates(e.g.,ribosomal small-subunit[SSU]processome component Mpp10,transcription factor p53,check-point proteins Chk1 and Wee1).This pathway relies on the Ca2þ-dependent cysteine proteinase CAPN3 and is independent of the ubiquitin-mediated proteasome pathway.CAPN3 is recruited by nucleolar protein Def from cytoplasm to nucleolus,where it proteolyzes its substrates which harbor a CAPN3 recognition-motif.Def depletion leads to the exclusion of CAPN3 and accumulation of p53,Wee1,Chk1,and Mpp10 in the nucleolus that result in cell-cycle arrest and rRNA processing abnormality.Here,we summarize the discovery of the Def-CAPN3 pathway and propose its biological role in cell-cycle control and ribosome biogenesis.展开更多
The nucleolus is a subnuclear structure of eukaryocytes. It was thought that nucleolus only participates in the biogenesis and processing of rRNA. However, more and more evidence shows that it has many other functions...The nucleolus is a subnuclear structure of eukaryocytes. It was thought that nucleolus only participates in the biogenesis and processing of rRNA. However, more and more evidence shows that it has many other functions, such as tRNA precursor processing, stress sensing and it is also involved in gene silencing, senescence and cell cycle regulation. Here, we summarize the recent understandings about the nucleolar functions, the regulation of nucleolar localization of proteins and the role that the nucleolus plays in virus infection, in which some related studies of Herpes simplex virus type 1 (HSV-1) US11, UL24 and bovine herpesvirus-1 infected cell protein 27 (BICP27) carried out in our lab will also be included.展开更多
Mitochondrial damage is closely related to the occurrence of many diseases.However,accurate monitoring and reporting of mitochondrial damage are not easy.Here,we developed a small molecule fluorescent probe named CB-C...Mitochondrial damage is closely related to the occurrence of many diseases.However,accurate monitoring and reporting of mitochondrial damage are not easy.Here,we developed a small molecule fluorescent probe named CB-Cl,which has splendid spectral properties(large Stokes shift,strong affinity for RNA,etc.)and excellent targeting ability to intracellular mitochondria.After mitochondria were damaged by external stimuli,CB-Cl would light up the nucleolus as a signal reporter.The cascade imaging of mitochondria and nucleolus using CB-Cl can monitor and visualize the mitochondrial status in living cells in real-time.Based on the above advantages,the probe CB-Cl has reference significance for the related research of mitochondrial damage and the prevention and treatment of related diseases.展开更多
In our conversation with Prof.CHEN Lingling on the"dark mat ter"in the genome,namely the non-coding RNAs,we got to know two classes of long non-coding RNAs(lncRNAs)in close association with Prader-Willi synd...In our conversation with Prof.CHEN Lingling on the"dark mat ter"in the genome,namely the non-coding RNAs,we got to know two classes of long non-coding RNAs(lncRNAs)in close association with Prader-Willi syndrome(PWS).Each with a snoRNA cap on its either end,they fall in the sno-lncRNA family,a group of lncRNAs identified by CHEN’s group in their earlier research.Here we are meeting another member of the family,SLERT,a rescuer展开更多
The dynamic changes of nucleolar ultrastructure in the cell cycle of Physarum polycephalum Schw. were studied by an en bloc silver-staining method. The results showed that the nucleolus was large in size and situated ...The dynamic changes of nucleolar ultrastructure in the cell cycle of Physarum polycephalum Schw. were studied by an en bloc silver-staining method. The results showed that the nucleolus was large in size and situated in the center of the nucleus in late G(2)-phase, and the fibrillar centers, dense fibrillar components and granular components could be observed in the nucleolus. During prophase, the nucleolus moved towards the periphery of the nucleus and in late prophase disintegrated near the nuclear envelope. in metaphase, the disintegrated nucleolar components were dispersed in masses and located at the periphery of the chromosomal region of the nucleus. No specifically silver-stained area and argentophilic protein sheath were observed on the chromosomes, but there were some big dispersed silver particles within the chromosomes. During telophase the nucleolar components moved towards the two poles along with the chromosomes and co-existed with the decondensing chromatin in daughter nuclei. The nucleolar components then gradually converged with one another and separated from the chromatin. A big nucleolus was formed in the nucleus about 120 min after the completion of mitosis.展开更多
本文结合DEA(Data Envelopment Analysis)和联盟博弈理论研究了固定成本分摊问题。本文首先证明了在固定成本作为决策单元(Decision Making Unit,DMU)新投入要素的条件下,那么DMU个体和整体将同为DEA有效,在此结论的基础上,本文结合联...本文结合DEA(Data Envelopment Analysis)和联盟博弈理论研究了固定成本分摊问题。本文首先证明了在固定成本作为决策单元(Decision Making Unit,DMU)新投入要素的条件下,那么DMU个体和整体将同为DEA有效,在此结论的基础上,本文结合联盟博弈理论,定义了联盟博弈的特征函数,提出了基于核仁解的固定成本分摊模型,并给出了相应的求解算法,最终通过算例说明了本文方法的合理性和求解算法的可行性。展开更多
文摘By using the DNA specific cytochemical staining method (NAMA_Ur) and conventional electron microscopic technique, the authors examined the configuration of intranucleolar DNA in Allium cepa L. cells and found that nucleolar DNA within the fibrillar center (FC) underwent a structural transformation process from condensed to extended state. The authors' observations also displayed a continuous arrangement process of nucleolar DNA, i.e., the extranucleolar DNA entered FC through the nucleolar organizer region (NOR) channel, then extended to the periphery of FC or to the border between FC and dense fibrillar component (DFC), and distributed along the periphery of FC. Thence, by passing through the NOR channel between FCs, the nucleolar DNA continued to transfer to other FCs and arranged in the same above_mentioned forms.
文摘The effects of different concentrations of cadmium chloride ranging from 0.5 to 20 ppm on the nucleolus in root tip cells of Allium cepa were studied using the silver staining technique. The results indicated that after the treatment with Cd￣(2+),different changes in nucleolar morphology appeared. The nucleolar material was extruded from the nucleus into the cytoplasm,and the nucleoli at mitotic metaphase did not disappear. Apparently,cadmium showed a specific effects on the nucleoli in root tip cells of Allium cepa. The possible mechanism behind this phenomenon is also briefly discussed.
文摘Processing of pre-rRNA is one of the major events taking place In the nucleolus. U3 snoRNA, an rRNA spliceosomal factor, is suggested to be essential in the first cleavage step of the 5' ETS sequence in the processing of pre-rRNA. Identification of U3 in the nucleolus provides a piece of indirect evidence for pre-rRNA processing site and transportation of processing products. In the present study, subnucleolar distribution of U3 snoRNA in the nucleolus of Pisum sativum L. was studied by in situ hybridization with a U3 snoRNA probe. The results showed that the U3 labeling signals were distributed throughout dense fibrillar components (DFCs) and granular components (GCs), while no signal was found in fibrillar centers (FCs). When treated with actinomycine D (AMD), the labeling signals were decreased. Along with the increase of the AMD treatment time, the labeling signals became fewer and they were found in the distal regions of DFC and GC. Our results indicated that pre-rRNA splicing took place in the regions of DFC and GC, and the transportation of pre-rRNA processing products was from the regions around FCs towards the distal regions.
文摘The nucleolus is the most prominent compartment in the nucleus and known as the site for ribosome biogenesis in eucaryotes. In contrast, there is no such equivalent structure for ribosome synthesis in procaryotes. This raises two concerns that how does the nucleolus evolve and that whether the nucleolus remains playing a single role in ribosome biogenesis along the evolution. Increasing data support new nucleolus functions, including signal recognition particle assembly, small RNA modification, telomerase maturation, cell-cycle and aging control, and cell stress sensor. Multiple functions of the nucleolus possibly result from the plurifunctionality of nucleolar proteins, such as nucleolin and Nopp 140. Proteomic analyses of human and Arabidopsis nucleolus lead a remarkable progress in understanding the evolution and new functions of nucleoli. In this review, we present a brief history of nucleolus research and new concepts and unresolved questions. Also, we introduce hepatitis D virus for studying the communication between the nucleolus and other subnuclear compartments, and Caenorhabditis elegans for the role of nucleolus in the development and the epistatic control of nucleologenesis.
基金the National Key R&D Program of China and the Natural Science Foundation of China in the order of 2018YFA0800502,2017YFA0504501,31330050.
文摘The nucleolus,as the‘nucleus of the nucleus’,is a prominent subcellular organelle in a eukaryocyte.The nucleolus serves as the centre for ribosome biogenesis,as well as an important site for cell-cycle regulation,cellular senescence,and stress response.The protein composition of the nucleolus changes dynamically through protein turnover to meet the needs of cellular activities or stress responses.Recent studies have identified a nucleolus-localized protein degradation pathway in zebrafish and humans,namely the Def-CAPN3 pathway,which is essential to ribosome production and cell-cycle progression,by controlling the turnover of multiple substrates(e.g.,ribosomal small-subunit[SSU]processome component Mpp10,transcription factor p53,check-point proteins Chk1 and Wee1).This pathway relies on the Ca2þ-dependent cysteine proteinase CAPN3 and is independent of the ubiquitin-mediated proteasome pathway.CAPN3 is recruited by nucleolar protein Def from cytoplasm to nucleolus,where it proteolyzes its substrates which harbor a CAPN3 recognition-motif.Def depletion leads to the exclusion of CAPN3 and accumulation of p53,Wee1,Chk1,and Mpp10 in the nucleolus that result in cell-cycle arrest and rRNA processing abnormality.Here,we summarize the discovery of the Def-CAPN3 pathway and propose its biological role in cell-cycle control and ribosome biogenesis.
基金The Startup Fund of the Hundred Talents Program of the Chinese Academy of Science (20071010141)National Natural Science Foundation of China(30870120)+1 种基金Open Research Fund Program of the State Key Laboratory of Virology of China (2007003, 2009007)Hubei Province Natural Science Foundation of Innovation Groups Project (2008CDA013)
文摘The nucleolus is a subnuclear structure of eukaryocytes. It was thought that nucleolus only participates in the biogenesis and processing of rRNA. However, more and more evidence shows that it has many other functions, such as tRNA precursor processing, stress sensing and it is also involved in gene silencing, senescence and cell cycle regulation. Here, we summarize the recent understandings about the nucleolar functions, the regulation of nucleolar localization of proteins and the role that the nucleolus plays in virus infection, in which some related studies of Herpes simplex virus type 1 (HSV-1) US11, UL24 and bovine herpesvirus-1 infected cell protein 27 (BICP27) carried out in our lab will also be included.
基金the Shenzhen Science and Technology Research and Development Funds(No.JCYJ20190806155409104)National Natural Science Foundation of China(Nos.52150222,21672130 and 52073163)+1 种基金Guangdong Basic and Applied Basic Research Foundation(No.2019A1515110356)the Qilu Young Scholars Program of Shandong University.
文摘Mitochondrial damage is closely related to the occurrence of many diseases.However,accurate monitoring and reporting of mitochondrial damage are not easy.Here,we developed a small molecule fluorescent probe named CB-Cl,which has splendid spectral properties(large Stokes shift,strong affinity for RNA,etc.)and excellent targeting ability to intracellular mitochondria.After mitochondria were damaged by external stimuli,CB-Cl would light up the nucleolus as a signal reporter.The cascade imaging of mitochondria and nucleolus using CB-Cl can monitor and visualize the mitochondrial status in living cells in real-time.Based on the above advantages,the probe CB-Cl has reference significance for the related research of mitochondrial damage and the prevention and treatment of related diseases.
文摘In our conversation with Prof.CHEN Lingling on the"dark mat ter"in the genome,namely the non-coding RNAs,we got to know two classes of long non-coding RNAs(lncRNAs)in close association with Prader-Willi syndrome(PWS).Each with a snoRNA cap on its either end,they fall in the sno-lncRNA family,a group of lncRNAs identified by CHEN’s group in their earlier research.Here we are meeting another member of the family,SLERT,a rescuer
文摘The dynamic changes of nucleolar ultrastructure in the cell cycle of Physarum polycephalum Schw. were studied by an en bloc silver-staining method. The results showed that the nucleolus was large in size and situated in the center of the nucleus in late G(2)-phase, and the fibrillar centers, dense fibrillar components and granular components could be observed in the nucleolus. During prophase, the nucleolus moved towards the periphery of the nucleus and in late prophase disintegrated near the nuclear envelope. in metaphase, the disintegrated nucleolar components were dispersed in masses and located at the periphery of the chromosomal region of the nucleus. No specifically silver-stained area and argentophilic protein sheath were observed on the chromosomes, but there were some big dispersed silver particles within the chromosomes. During telophase the nucleolar components moved towards the two poles along with the chromosomes and co-existed with the decondensing chromatin in daughter nuclei. The nucleolar components then gradually converged with one another and separated from the chromatin. A big nucleolus was formed in the nucleus about 120 min after the completion of mitosis.
文摘本文结合DEA(Data Envelopment Analysis)和联盟博弈理论研究了固定成本分摊问题。本文首先证明了在固定成本作为决策单元(Decision Making Unit,DMU)新投入要素的条件下,那么DMU个体和整体将同为DEA有效,在此结论的基础上,本文结合联盟博弈理论,定义了联盟博弈的特征函数,提出了基于核仁解的固定成本分摊模型,并给出了相应的求解算法,最终通过算例说明了本文方法的合理性和求解算法的可行性。
