scholarly journals CHO1, a mammalian kinesin-like protein, interacts with F-actin and is involved in the terminal phase of cytokinesis

2002 ◽  
Vol 156 (5) ◽  
pp. 783-790 ◽  
Author(s):  
Ryoko Kuriyama ◽  
Charles Gustus ◽  
Yasuhiko Terada ◽  
Yumi Uetake ◽  
Jurgita Matuliene
Keyword(s):  
Alternative Splicing ◽  
Single Cell ◽  
Mammalian Cells ◽  
Genomic Sequence ◽  
Terminal Phase ◽  
Inhibitory Effects ◽  
Contractile Ring ◽  
Specific Antibodies ◽  
Daughter Cells ◽  
Tail Analysis

CHO1 is a kinesin-like protein of the mitotic kinesin-like protein (MKLP)1 subfamily present in central spindles and midbodies in mammalian cells. It is different from other subfamily members in that it contains an extra ∼300 bp in the COOH-terminal tail. Analysis of the chicken genomic sequence showed that heterogeneity is derived from alternative splicing, and exon 18 is expressed in only the CHO1 isoform. CHO1 and its truncated isoform MKLP1 are coexpressed in a single cell. Surprisingly, the sequence encoded by exon 18 possesses a capability to interact with F-actin, suggesting that CHO1 can associate with both microtubule and actin cytoskeletons. Microinjection of exon 18–specific antibodies did not result in any inhibitory effects on karyokinesis and early stages of cytokinesis. However, almost completely separated daughter cells became reunited to form a binulceate cell, suggesting that the exon 18 protein may not have a role in the formation and ingression of the contractile ring in the cortex. Rather, it might be involved directly or indirectly in the membrane events necessary for completion of the terminal phase of cytokinesis.

scholarly journals An Essential Role for a Membrane Lipid in Cytokinesis

2000 ◽  
Vol 149 (6) ◽  
pp. 1215-1224 ◽  
Author(s):  
Kazuo Emoto ◽  
Masato Umeda
Keyword(s):  
Cell Surface ◽  
Mammalian Cells ◽  
Mutant Cell ◽  
Myosin Ii ◽  
Membrane Lipid ◽  
Cleavage Furrow ◽  
Contractile Ring ◽  
Cytoplasmic Bridge ◽  
Daughter Cells

Phosphatidylethanolamine (PE) is a major membrane phospholipid that is mainly localized in the inner leaflet of the plasma membrane. We previously demonstrated that PE was exposed on the cell surface of the cleavage furrow during cytokinesis. Immobilization of cell surface PE by a PE-binding peptide inhibited disassembly of the contractile ring components, including myosin II and radixin, resulting in formation of a long cytoplasmic bridge between the daughter cells. This blockade of contractile ring disassembly was reversed by removal of the surface-bound peptide, suggesting that the PE exposure plays a crucial role in cytokinesis. To further examine the role of PE in cytokinesis, we established a mutant cell line with a specific decrease in the cellular PE level. On the culture condition in which the cell surface PE level was significantly reduced, the mutant ceased cell growth in cytokinesis, and the contractile ring remained in the cleavage furrow. Addition of PE or ethanolamine, a precursor of PE synthesis, restored the cell surface PE on the cleavage furrow and normal cytokinesis. These findings provide the first evidence that PE is required for completion of cytokinesis in mammalian cells, and suggest that redistribution of PE on the cleavage furrow may contribute to regulation of contractile ring disassembly.

Mammalian cells have two functional RCC1 proteins produced by alternative splicing

1994 ◽  
Vol 107 (8) ◽  
pp. 2203-2208 ◽  
Author(s):  
J. Miyabashira ◽  
T. Sekiguchi ◽  
T. Nishimoto
Keyword(s):  
Amino Acids ◽  
Alternative Splicing ◽  
Nucleotide Sequence ◽  
Cell Line ◽  
Mammalian Cells ◽  
Genomic Sequence ◽  
Terminal Region ◽  
Noncoding Region ◽  
Coding Region

Previously we cloned two human RCC1 cDNAs that differed in their noncoding region. In this study, we have found new human and hamster RCC1 cDNAs, which have an even more different coding region from that of the previously cloned RCC1 cDNAs yet can complement the RCC1 mutation in the tsBN2 cell line. The newly found RCC1 cDNAs encode a protein (designated as RCC1-I) that has an insertion of 31 (human) and 13 (hamster) amino acids at valine25 in the N-terminal region outside the RCC1-seven repeat. The inserted nucleotide sequence was searched for, within the human RCC1 genomic sequence that had already been determined, and was found to be located between the 6th and 7th exons, designated as the 6′ exon. Both the 5′ and 3′ ends of the 6′ exon correspond to the GT-AG rules for splicing, indicating that human RCC1-I mRNAs are produced by alternative splicing. The finding that both humans and hamsters have the insertion at the same RCC1 site suggests that the pattern of alternative splicing in the RCC1 gene has been conserved through evolution.

Membrane traffic in cytokinesis

2005 ◽  
Vol 33 (6) ◽  
pp. 1290-1294 ◽  
Author(s):  
J. Matheson ◽  
X. Yu ◽  
A.B. Fielding ◽  
G.W. Gould
Keyword(s):  
Plasma Membrane ◽  
Membrane Trafficking ◽  
Mammalian Cells ◽  
Membrane Traffic ◽  
Protein Composition ◽  
Early Event ◽  
Contractile Ring ◽  
Purse String ◽  
Daughter Cells ◽  
Spatial Coordinates

A crucial facet of mammalian cell division is the separation of two daughter cells by a process known as cytokinesis. An early event in cytokinesis is the formation of an actomyosis contractile ring, which functions like a purse string in the constriction of the forming furrow between the cells. Far less well characterized are the membrane-trafficking steps which deliver new membrane to the cell surface during the plasma membrane expansion known to accompany furrow formation. It is now clearly established that the plasma membrane at the cleavage furrow of mammalian cells has a distinct lipid and protein composition from the rest of the plasma membrane. This may reflect a requirement for both increased surface area during furrowing and for the co-ordinated delivery of intracellular signalling or membrane re-modelling activities to the correct spatial coordinates during cleavage. In this review, we discuss recent work within the area of membrane traffic and cytokinesis.

scholarly journals Antiviral Compounds for Blocking Arboviral Transmission in Mosquitoes

Viruses ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 108
Author(s):  
Shengzhang Dong ◽  
George Dimopoulos
Keyword(s):  
High Throughput Screening ◽  
Mammalian Cells ◽  
Symbiotic Bacterium ◽  
Screening Methods ◽  
Human Pathogens ◽  
Inhibitory Effects ◽  
Antiviral Compounds ◽  
Mosquito Cells ◽  
Recent Emergence ◽  
Arboviral Transmission

Mosquito-borne arthropod-borne viruses (arboviruses) such as the dengue virus (DENV), Zika virus (ZIKV), and chikungunya virus (CHIKV) are important human pathogens that are responsible for significant global morbidity and mortality. The recent emergence and re-emergence of mosquito-borne viral diseases (MBVDs) highlight the urgent need for safe and effective vaccines, therapeutics, and vector-control approaches to prevent MBVD outbreaks. In nature, arboviruses circulate between vertebrate hosts and arthropod vectors; therefore, disrupting the virus lifecycle in mosquitoes is a major approach for combating MBVDs. Several strategies were proposed to render mosquitoes that are refractory to arboviral infection, for example, those involving the generation of genetically modified mosquitoes or infection with the symbiotic bacterium Wolbachia. Due to the recent development of high-throughput screening methods, an increasing number of drugs with inhibitory effects on mosquito-borne arboviruses in mammalian cells were identified. These antivirals are useful resources that can impede the circulation of arboviruses between arthropods and humans by either rendering viruses more vulnerable in humans or suppressing viral infection by reducing the expression of host factors in mosquitoes. In this review, we summarize recent advances in small-molecule antiarboviral drugs in mammalian and mosquito cells, and discuss how to use these antivirals to block the transmission of MBVDs.

scholarly journals Adhesion-dependent and Contractile Ring-independent Equatorial Furrowing during Cytokinesis in Mammalian Cells

2005 ◽  
Vol 16 (8) ◽  
pp. 3865-3872 ◽  
Author(s):  
Masamitsu Kanada ◽  
Akira Nagasaki ◽  
Taro Q.P. Uyeda
Keyword(s):  
Mammalian Cells ◽  
Rat Kidney ◽  
Myosin Ii ◽  
Rho Kinase ◽  
Cellular Slime Mold ◽  
Animal Cells ◽  
Contractile Ring ◽  
Normal Rat ◽  
Cellular Slime ◽  
Coated Surfaces

Myosin II-dependent contraction of the contractile ring drives equatorial furrowing during cytokinesis in animal cells. Nonetheless, myosin II-null cells of the cellular slime mold Dictyostelium divide efficiently when adhering to substrates by making use of polar traction forces. Here, we show that in the presence of 30 μM blebbistatin, a potent myosin II inhibitor, normal rat kidney (NRK) cells adhering to fibronectin-coated surfaces formed equatorial furrows and divided in a manner strikingly similar to myosin II-null Dictyostelium cells. Such blebbistatin-resistant cytokinesis was absent in partially detached NRK cells and was disrupted in adherent cells if the advance of their polar lamellipodia was disturbed by neighboring cells. Y-27632 (40 μM), which inhibits Rho-kinase, was similar to 30 μM blebbistatin in that it inhibited cytokinesis of partially detached NRK cells but only prolonged furrow ingression in attached cells. In the presence of 100 μM blebbistatin, most NRK cells that initiated anaphase formed tight furrows, although scission never occurred. Adherent HT1080 fibrosarcoma cells also formed equatorial furrows efficiently in the presence of 100 μM blebbistatin. These results provide direct evidence for adhesion-dependent, contractile ring-independent equatorial furrowing in mammalian cells and demonstrate the importance of substrate adhesion for cytokinesis.

scholarly journals Expression of Alternatively Spliced Sodium Channel α-Subunit Genes

2004 ◽  
Vol 279 (44) ◽  
pp. 46234-46241 ◽  
Author(s):  
Christopher K. Raymond ◽  
John Castle ◽  
Philip Garrett-Engele ◽  
Christopher D. Armour ◽  
Zhengyan Kan ◽  
...  
Keyword(s):  
Alternative Splicing ◽  
Sodium Channel ◽  
Dorsal Root Ganglia ◽  
Dorsal Root ◽  
Genomic Sequence ◽  
Molecular Medicine ◽  
Primate Model ◽  
Α Subunit ◽  
Alternatively Spliced ◽  
Splicing Patterns

Molecular medicine requires the precise definition of drug targets, and tools are now in place to provide genome-wide information on the expression and alternative splicing patterns of any known gene. DNA microarrays were used to monitor transcript levels of the nine well-characterized α-subunit sodium channel genes across a broad range of tissues from cynomolgus monkey, a non-human primate model. Alternative splicing of human transcripts for a subset of the genes that are expressed in dorsal root ganglia, SCN8A (Nav1.6), SCN9A (Nav1.7), and SCN11A (Nav1.9) was characterized in detail. Genomic sequence analysis among gene family paralogs and between cross-species orthologs suggested specific alternative splicing events within transcripts of these genes, all of which were experimentally confirmed in human tissues. Quantitative PCR revealed that certain alternative splice events are uniquely expressed in dorsal root ganglia. In addition to characterization of human transcripts, alternatively spliced sodium channel transcripts were monitored in a rat model for neuropathic pain. Consistent down-regulation of all transcripts was observed, as well as significant changes in the splicing patterns of SCN8A and SCN9A.

scholarly journals Single-cell Differential Splicing Analysis Reveals High Heterogeneity of Liver Tumor-infiltrating T Cells

2020 ◽  
Author(s):  
Shang Liu ◽  
Biaofeng Zhou ◽  
Liang Wu ◽  
Yan Sun ◽  
Jie Chen ◽  
...  
Keyword(s):  
T Cells ◽  
Alternative Splicing ◽  
T Cell ◽  
Single Cell ◽  
Regulatory Factor ◽  
Differential Splicing ◽  
Cell Level ◽  
Comprehensive Investigation ◽  
Cancer Initiation ◽  
Cell Groups

Abstract Recent advances in single-cell RNA sequencing (scRNA-seq) have improved our understanding of the association between tumor-infiltrating lymphocyte (TILs) heterogeneity and cancer initiation and progression. However, studies investigating alternative splicing (AS) as an important regulatory factor of heterogeneity remain limited. Here, we developed a new computational tool, DESJ-detection, which accurately detects differentially expressed splicing junctions (DESJs) between cell groups at the single-cell level. We analyzed 5,063 T cells of hepatocellular carcinoma (HCC) and identified 1,176 DESJs across 11 T cell subtypes. Interestingly, DESJs were enriched in UTRs, and have putative effects on heterogeneity. Cell subtypes with a similar function closely clustered together at the AS level. Meanwhile, we identified two novel cell states, pre-exhaustion and pre-activation with the isoform markers CD103-201 and ARHGAP15-205. In summary, we present a comprehensive investigation of alternative splicing differences, which provided novel insights into T cell heterogeneity and can be applied to other full-length scRNA-seq datasets.

A centrosome-associated antibody from Drosophila melanogaster reveals a new microtubule-dependent structure in the equatorial zone of Parascaris univalens embryos

1993 ◽  
Vol 106 (3) ◽  
pp. 719-730
Author(s):  
M. Jimenez ◽  
C. Goday
Keyword(s):  
Drosophila Melanogaster ◽  
Cytochalasin B ◽  
Cell Communication ◽  
Equatorial Zone ◽  
Contractile Ring ◽  
Daughter Cells ◽  
Ring Assembly ◽  
Single Body ◽  
A Cell ◽  
Cycle Dependent

The distribution of antigens to two antibodies (Bx63 and Rb188) that associate to Drosophila melanogaster centrosomes has been investigated in the nematode Parascaris. By western blot analysis both antibodies identify in Parascaris polypeptides of the same molecular mass as in Drosophila (Rb188 a 185 kDa antigen and Bx63 185 kDa and 66 kDa antigens). By immunocytochemistry we show that the centrosomes of Parascaris contain the 185 kDa antigen recognized by polyclonal Rb188 and monoclonal Bx63 antibodies. In addition, Bx63 reveals cytoplasmic midzone structures, not found in Drosophila, that display a cell cycle-dependent organization in embryos. These structures, which most probably contain the 66 kDa antigen revealed by Bx63, appear at the onset of anaphase as fibrillar-like structures that during anaphase form a ring-like structure encircling the equatorial plane of the blastomere. Before furrowing, the antigen participates in the formation of the midbody and associates with convergent polar microtubules. After blastomere division, Bx63 signal persists as a single body between the daughter cells. The analysis of chilled and nocodazole-treated embryos suggests that the localization of the midzone Bx63 antigen is dependent on non-kinetochore microtubules. Inhibition of furrowing by cytochalasin B shows that the antigen persists after the disassembly of microfilaments. Cytological observations of contractile ring and Bx63 ring assembly indicate that both structures do not simultaneously colocalize at the equatorial zone. The data suggest a spindle-dependent distribution of the Bx63 antigen during cytokinesis. We discuss the participation of this antigen in the organization of the midbody before furrowing, and consider the possible relevance of the midbody with respect to cell to cell communication during early development in nematodes.

Mapping replication timing domains genome wide in single mammalian cells with single-cell DNA replication sequencing

2020 ◽  
Vol 15 (12) ◽  
pp. 4058-4100
Author(s):  
Hisashi Miura ◽  
Saori Takahashi ◽  
Takahiro Shibata ◽  
Koji Nagao ◽  
Chikashi Obuse ◽  
...  
Keyword(s):  
Dna Replication ◽  
Single Cell ◽  
Mammalian Cells ◽  
Replication Timing ◽  
Genome Wide
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