synchronous pollen mitosis and the formation of the generative cell
... to those Unking the meiocytes in non-massulate angiosperms and they are of comparable dimensions (Heslop-Harrison, 1964, 19666). In non-massulate species, the links between the meiocytes are normally eliminated before meiosis II, and none is formed at all between the sister spores of a tetrad, but i ...
... to those Unking the meiocytes in non-massulate angiosperms and they are of comparable dimensions (Heslop-Harrison, 1964, 19666). In non-massulate species, the links between the meiocytes are normally eliminated before meiosis II, and none is formed at all between the sister spores of a tetrad, but i ...
DNA polymerase alpha, a component of the replication initiation
... the assembly of a replication initiation complex in vitro involves binding of an origin-binding protein to a site of initiation, or origin (Dean et al., 1987), followed by binding of RP-A, which facilitates origin unwinding (reviewed by Stillman, 1989), and DNA polymerase alpha/primase, which is req ...
... the assembly of a replication initiation complex in vitro involves binding of an origin-binding protein to a site of initiation, or origin (Dean et al., 1987), followed by binding of RP-A, which facilitates origin unwinding (reviewed by Stillman, 1989), and DNA polymerase alpha/primase, which is req ...
IUG - CELL BIO - E
... has been discovered that many membranes, including the plasma membrane, have a complex internal structure. The small globular particles seen in these membranes are thought to be membrane proteins that lie within the membrane lipid bilayer .The most widely accepted current model for membrane structur ...
... has been discovered that many membranes, including the plasma membrane, have a complex internal structure. The small globular particles seen in these membranes are thought to be membrane proteins that lie within the membrane lipid bilayer .The most widely accepted current model for membrane structur ...
Chromosomes with Two Intact Axial Cores Are Induced by G2
... et al., 1994). A drug block with any of several agents that interfere with topo II enzyme activity, such as VM-26 and ICRF-193, imposes a checkpoint on cell cycle progression in which the cell arrests in G2 with undecatenated DNA. We have demonstrated, in a previous study, that when mammalian cells ...
... et al., 1994). A drug block with any of several agents that interfere with topo II enzyme activity, such as VM-26 and ICRF-193, imposes a checkpoint on cell cycle progression in which the cell arrests in G2 with undecatenated DNA. We have demonstrated, in a previous study, that when mammalian cells ...
Making parallel lines meet
... to spaces both fascinating and useful. A contemporary case of parallel lines whose meeting is impossible but informative is offered by the humble vascular plant. Perhaps of doubtful utility for readers of Cell Adhesion and Migration, this case nevertheless could fascinate them, concerning as it does ...
... to spaces both fascinating and useful. A contemporary case of parallel lines whose meeting is impossible but informative is offered by the humble vascular plant. Perhaps of doubtful utility for readers of Cell Adhesion and Migration, this case nevertheless could fascinate them, concerning as it does ...
Inductive asymmetric cell division
... and low in the posterior sister E,20,21 while WRM-1 is low in MS cortex of the dividing EMS blastomere. APR-1, a worm homolog and high in E.22 wrm-1 and pop-1 mutants also exhibit opposite of APC (adenomatous polyposis coli protein), is also recruited to endoderm induction phenotypes; in wrm-1 mutan ...
... and low in the posterior sister E,20,21 while WRM-1 is low in MS cortex of the dividing EMS blastomere. APR-1, a worm homolog and high in E.22 wrm-1 and pop-1 mutants also exhibit opposite of APC (adenomatous polyposis coli protein), is also recruited to endoderm induction phenotypes; in wrm-1 mutan ...
Micromechanical studies of mitotic chromosomes
... diameter, possibly with a helical structure. However, little else about supranucleosomal organization (‘higherorder chromatin structure’) is solidly understood. This is a result of the relative softness of chromatin fiber, which leads to chromatin’s apparent flexible-polymer properties (Cui and Bustam ...
... diameter, possibly with a helical structure. However, little else about supranucleosomal organization (‘higherorder chromatin structure’) is solidly understood. This is a result of the relative softness of chromatin fiber, which leads to chromatin’s apparent flexible-polymer properties (Cui and Bustam ...
Two Microtubule-Associated Proteins of the
... polymerization. It also induced the formation of large microtubule bundles by forming cross-bridges between microtubules evenly along the whole length of microtubules. In the presence of AtMAP65-1, microtubule bundles were more resistant to cold and dilution treatments. AtMAP65-6, however, demonstra ...
... polymerization. It also induced the formation of large microtubule bundles by forming cross-bridges between microtubules evenly along the whole length of microtubules. In the presence of AtMAP65-1, microtubule bundles were more resistant to cold and dilution treatments. AtMAP65-6, however, demonstra ...
The Myriad Roles of Anillin during Cytokinesis Alisa J. Piekny1 and
... throughout the cellularization front ([8]; Fig. 1). Depletion of Drosophila or human Anillin from cultured cells perturbs the temporal and spatial stability of myosin at the cell equator during cytokinesis [12, 13, 18, 20-22]. C. elegans Anillin (ANI-1) organizes myosin into dynamic foci during pola ...
... throughout the cellularization front ([8]; Fig. 1). Depletion of Drosophila or human Anillin from cultured cells perturbs the temporal and spatial stability of myosin at the cell equator during cytokinesis [12, 13, 18, 20-22]. C. elegans Anillin (ANI-1) organizes myosin into dynamic foci during pola ...
Expansion of the phragmoplast during plant cytokinesis: a MAPK
... vesicles is the phragmoplast, whose formation is initiated during late anaphase [1]. A phragmoplast complex is composed of two bundles of anti-parallel microtubules (MTs) and actin filaments. MTs are, in general, orientated and consist of a plus end and a minus end. The MTs overlap at their plus end ...
... vesicles is the phragmoplast, whose formation is initiated during late anaphase [1]. A phragmoplast complex is composed of two bundles of anti-parallel microtubules (MTs) and actin filaments. MTs are, in general, orientated and consist of a plus end and a minus end. The MTs overlap at their plus end ...
The roles of microtubules in tropisms
... possible locations. Shoots grow towards light, maximizing photosynthetic activity. Roots point down along the gravity vector and can be attracted to areas of higher moisture or nutrient content in the soil. When conditions change, plants respond by redirecting their growth in accordance with the new ...
... possible locations. Shoots grow towards light, maximizing photosynthetic activity. Roots point down along the gravity vector and can be attracted to areas of higher moisture or nutrient content in the soil. When conditions change, plants respond by redirecting their growth in accordance with the new ...
Coordination of Cell Cycle Progression and Mitotic
... yeast. In human cells it is well established that E2F transcription factors employ Set1 and MLL1 H3K4 methyltransferases during the G1-S transition (Tyagi et al. 2007). Interestingly, the Set1C complex has been involved in the regulation of chromosome segregation during mitosis (Zhang et al. 2005). ...
... yeast. In human cells it is well established that E2F transcription factors employ Set1 and MLL1 H3K4 methyltransferases during the G1-S transition (Tyagi et al. 2007). Interestingly, the Set1C complex has been involved in the regulation of chromosome segregation during mitosis (Zhang et al. 2005). ...
A Cytochemical Study of the Stem Cell Concept in Specimens o£ a
... in the continuation of definitive genotypes which may or may not contain the chromosome number characteristic of the species. The genetic aspect of this concept concerns itself with the selective action of the environment upon the cell population. The concept states that the conditions of growth inf ...
... in the continuation of definitive genotypes which may or may not contain the chromosome number characteristic of the species. The genetic aspect of this concept concerns itself with the selective action of the environment upon the cell population. The concept states that the conditions of growth inf ...
Plk4/SAK/ZYG-1 in the regulation of centriole
... studies describing the regulation and a downstream target of Plk4/SAK/ZYG-1 protein kinases has begun to describe the complexity of this process. Perhaps the most intriguing feature of these studies is the observation that Plk4/SAK activity peaks at mitosis and promotes maintenance of Sas6 during th ...
... studies describing the regulation and a downstream target of Plk4/SAK/ZYG-1 protein kinases has begun to describe the complexity of this process. Perhaps the most intriguing feature of these studies is the observation that Plk4/SAK activity peaks at mitosis and promotes maintenance of Sas6 during th ...
The Cortical Microtubule Array: From Dynamics to
... (A) Microtubules are composed of a/b-tubulin heterodimers that are assembled in a head-to-tail fashion to form linear protofilaments that associate laterally within the typical 13-protofilament, 25-nm microtubule. The b-tubulin end is fast growing and the more dynamic end (1end), whereas the a-tubul ...
... (A) Microtubules are composed of a/b-tubulin heterodimers that are assembled in a head-to-tail fashion to form linear protofilaments that associate laterally within the typical 13-protofilament, 25-nm microtubule. The b-tubulin end is fast growing and the more dynamic end (1end), whereas the a-tubul ...
Adenomatous polyposis coli - Journal of Cell Science
... transcriptional repressor C-terminal binding protein (CtBP) and forms a stable complex with additional co-repressors TLE1 and HDAC1 (Hamada and Bienz, 2004; Sierra et al., 2006). Because APC interacts with TrCP at the MYC enhancer, it may facilitate CtBP-mediated repression of Wnt-target genes (Ham ...
... transcriptional repressor C-terminal binding protein (CtBP) and forms a stable complex with additional co-repressors TLE1 and HDAC1 (Hamada and Bienz, 2004; Sierra et al., 2006). Because APC interacts with TrCP at the MYC enhancer, it may facilitate CtBP-mediated repression of Wnt-target genes (Ham ...
Cell Cycle in the Fucus Zygote Parallels a Somatic Cell
... in each lane, and RNA integrity was checked by staining with ethidium bromide (data not shown). Corresponding quantifications (right) were performed with a phosphorimager in control zygotes (open circles) as well as in zygotes treated from 3 hr AF with either 20 M aphidicolin (closed squares) or 10 ...
... in each lane, and RNA integrity was checked by staining with ethidium bromide (data not shown). Corresponding quantifications (right) were performed with a phosphorimager in control zygotes (open circles) as well as in zygotes treated from 3 hr AF with either 20 M aphidicolin (closed squares) or 10 ...
Detergentsalt resistance of LAP2 in interphase nuclei and
... findings suggest that at least some of these proteins might also be directly involved in chromatin organization. p58/ LBR and LAP2 have been shown to associate with chromosomes and chromatin in vitro (Foisner and Gerace, 1993; Pyrpasopoulou et al., 1996), and might provide essential chromatin dockin ...
... findings suggest that at least some of these proteins might also be directly involved in chromatin organization. p58/ LBR and LAP2 have been shown to associate with chromosomes and chromatin in vitro (Foisner and Gerace, 1993; Pyrpasopoulou et al., 1996), and might provide essential chromatin dockin ...
Expression of a Nondegradable Cyclin B1 Affects
... subcellular localizations, as well as their stabilities during the cell cycle are only poorly understood (Criqui and Genschik, 2002). We have previously demonstrated in synchronized Nicotiana tabacum (tobacco) BY2 cells that endogenous cyclin B1;1 protein undergoes cell cycle–dependent proteolysis a ...
... subcellular localizations, as well as their stabilities during the cell cycle are only poorly understood (Criqui and Genschik, 2002). We have previously demonstrated in synchronized Nicotiana tabacum (tobacco) BY2 cells that endogenous cyclin B1;1 protein undergoes cell cycle–dependent proteolysis a ...
Expression of a Nondegradable Cyclin B1 Affects
... subcellular localizations, as well as their stabilities during the cell cycle are only poorly understood (Criqui and Genschik, 2002). We have previously demonstrated in synchronized Nicotiana tabacum (tobacco) BY2 cells that endogenous cyclin B1;1 protein undergoes cell cycle–dependent proteolysis a ...
... subcellular localizations, as well as their stabilities during the cell cycle are only poorly understood (Criqui and Genschik, 2002). We have previously demonstrated in synchronized Nicotiana tabacum (tobacco) BY2 cells that endogenous cyclin B1;1 protein undergoes cell cycle–dependent proteolysis a ...
Mitotic replication initiation proteins are not required for pre
... Assaying S phase in pat1 mutants To facilitate the study of genes involved in meiS phase, we used a temperature-sensitive mutation in the essential Pat1p protein kinase10,11. If shifted to the restrictive temperature, pat1 mutants proceed through meiotic DNA replication and both meiotic divisions in ...
... Assaying S phase in pat1 mutants To facilitate the study of genes involved in meiS phase, we used a temperature-sensitive mutation in the essential Pat1p protein kinase10,11. If shifted to the restrictive temperature, pat1 mutants proceed through meiotic DNA replication and both meiotic divisions in ...
Metaplastic carcinoma of the breast: A clinicopathological review
... spindle cell carcinomas to arise from pre-existing lesions, including Papillomas, Complex sclerosing lesions and nipple adenomas (3,4). Metaplastic or Spindle cell carcinoma arising from such lesions can show a varying degree of malignancy, ranging fromlow to high grade. This type of lesion should a ...
... spindle cell carcinomas to arise from pre-existing lesions, including Papillomas, Complex sclerosing lesions and nipple adenomas (3,4). Metaplastic or Spindle cell carcinoma arising from such lesions can show a varying degree of malignancy, ranging fromlow to high grade. This type of lesion should a ...
The Distribution of Polycomb-Group Proteins During Cell Division
... 1991). It may be assumed that a better understanding of the mechanism of PcG-mediated repression in Drosophila will have broad ramifications with respect to the problem of developmental control in higher eukaryotes. However, neither a description of the molecular interactions by which PcG repression ...
... 1991). It may be assumed that a better understanding of the mechanism of PcG-mediated repression in Drosophila will have broad ramifications with respect to the problem of developmental control in higher eukaryotes. However, neither a description of the molecular interactions by which PcG repression ...
Imaging the fate of histone Cse4 reveals de novo replacement in S
... eLife digest When cells multiply, it is essential for each new cell to get a copy of the organism's genetic blueprint. If an error occurs during cell division, and one of the daughter cells ends up with too many or too few copies of a chromosome, the cell can die or malfunction. Errors during cell d ...
... eLife digest When cells multiply, it is essential for each new cell to get a copy of the organism's genetic blueprint. If an error occurs during cell division, and one of the daughter cells ends up with too many or too few copies of a chromosome, the cell can die or malfunction. Errors during cell d ...
Spindle checkpoint
During the process of cell division, the spindle checkpoint prevents separation of the duplicated chromosomes until each chromosome is properly attached to the spindle apparatus. In order to preserve the cell's identity and proper function, it is necessary to maintain the appropriate number of chromosomes after each cell division. An error in generating daughter cells with fewer or greater number of chromosomes than expected (a situation termed aneuploidy), may lead in best case to cell death, or alternatively it may generate catastrophic phenotypic results. Examples include: In cancer cells, aneuploidy is a frequent event, indicating that these cells present a defect in the machinery involved in chromosome segregation, as well as in the mechanism ensuring that segregation is correctly performed. In humans, Down syndrome appears in children carrying in their cells one extra copy of chromosome 21, as a result of a defect in chromosome segregation during meiosis in one of the progenitors. This defect will generate a gamete (spermatozoide or oocyte) with an extra chromosome 21. After fecundation, this gamete will generate an embryo with three copies of chromosome 21.The mechanisms verifying that all the requirements to pass to the next phase in the cell cycle have been fulfilled are called checkpoints. All along the cell cycle, there are different checkpoints. The checkpoint ensuring that chromosome segregation is correct is termed spindle assembly checkpoint (SAC), spindle checkpoint or mitotic checkpoint. During mitosis or meiosis, the spindle checkpoint prevents anaphase onset until all chromosomes are properly attached to the spindle. To achieve proper segregation, the two kinetochores on the sister chromatids must be attached to opposite spindle poles (bipolar orientation). Only this pattern of attachment will ensure that each daughter cell receives one copy of the chromosome.