scholarly journals Comparison of the generic neuronal differentiation and neuron subtype specification functions of mammalian achaete-scute and atonal homologs in cultured neural progenitor cells

Development ◽  
2002 ◽  
Vol 129 (7) ◽  
pp. 1553-1567 ◽  
Author(s):  
Liching Lo ◽  
Emma Dormand ◽  
Amy Greenwood ◽  
David J. Anderson
Keyword(s):  
Cell Cycle ◽  
Neuronal Differentiation ◽  
Neural Progenitor Cells ◽  
Proneural Genes ◽  
Neural Crest Stem Cells ◽  
Cycle Arrest ◽  
Bhlh Factors ◽  
High Concentrations ◽  
Autonomic Markers ◽  
Dependent Lineages

In the vertebrate peripheral nervous system, the proneural genes neurogenin 1 and neurogenin 2 (Ngn1 and Ngn2), and Mash1 are required for sensory and autonomic neurogenesis, respectively. In cultures of neural tube-derived, primitive PNS progenitors NGNs promote expression of sensory markers and MASH1 that of autonomic markers. These effects do not simply reflect enhanced neuronal differentiation, suggesting that both bHLH factors also specify neuronal identity like their Drosophila counterparts. At high concentrations of BMP2 or in neural crest stem cells (NCSCs), however, NGNs like MASH1 promote only autonomic marker expression. These data suggest that that the identity specification function of NGNs is more sensitive to context than is that of MASH1. In NCSCs, MASH1 is more sensitive to Notch-mediated inhibition of neurogenesis and cell cycle arrest, than are the NGNs. Thus, the two proneural genes differ in other functional properties besides the neuron subtype identities they can promote. These properties may explain cellular differences between MASH1- and NGN-dependent lineages in the timing of neuronal differentiation and cell cycle exit.

scholarly journals Omega-3 Polyunsaturated Fatty Acids Enhance Neuronal Differentiation in Cultured Rat Neural Stem Cells

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Masanori Katakura ◽  
Michio Hashimoto ◽  
Toshiyuki Okui ◽  
Hossain Md Shahdat ◽  
Kentaro Matsuzaki ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Fatty Acids ◽  
Stem Cells ◽  
Polyunsaturated Fatty Acids ◽  
Neural Stem Cells ◽  
Cell Cycle Arrest ◽  
Neuronal Differentiation ◽  
Mrna Levels ◽  
Cycle Arrest ◽  
Hes1 Expression

Polyunsaturated fatty acids (PUFAs) can induce neurogenesis and recovery from brain diseases. However, the exact mechanisms of the beneficial effects of PUFAs have not been conclusively described. We recently reported that docosahexaenoic acid (DHA) induced neuronal differentiation by decreasing Hes1 expression and increasingp27kip1expression, which causes cell cycle arrest in neural stem cells (NSCs). In the present study, we examined the effect of eicosapentaenoic acid (EPA) and arachidonic acid (AA) on differentiation, expression of basic helix-loop-helix transcription factors (Hes1, Hes6, and NeuroD), and the cell cycle of cultured NSCs. EPA also increased mRNA levels of Hes1, an inhibitor of neuronal differentiation, Hes6, an inhibitor of Hes1, NeuroD, and Map2 mRNA and Tuj-1-positive cells (a neuronal marker), indicating that EPA induced neuronal differentiation. EPA increased the mRNA levels ofp21cip1andp27kip1, a cyclin-dependent kinase inhibitor, which indicated that EPA induced cell cycle arrest. Treatment with AA decreased Hes1 mRNA but did not affect NeuroD and Map2 mRNA levels. Furthermore, AA did not affect the number of Tuj-1-positive cells or cell cycle progression. These results indicated that EPA could be involved in neuronal differentiation by mechanisms alternative to those of DHA, whereas AA did not affect neuronal differentiation in NSCs.

scholarly journals Basic Helix-Loop-Helix Proteins Bind to TrkB and p21Cip1 Promoters Linking Differentiation and Cell Cycle Arrest in Neuroblastoma Cells

2004 ◽  
Vol 24 (7) ◽  
pp. 2662-2672 ◽  
Author(s):  
Yuhui Liu ◽  
Mario Encinas ◽  
Joan X. Comella ◽  
Martí Aldea ◽  
Carme Gallego
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Neuronal Differentiation ◽  
Ectopic Expression ◽  
Neurotrophin Receptor ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
Cycle Arrest ◽  
E Box ◽  
Bhlh Proteins

ABSTRACT Differentiation of precursor into specialized cells involves an increasing restriction in proliferative capacity, culminating in cell cycle exit. In this report we used a human neuroblastoma cell line to study the molecular mechanisms that coordinate cell cycle arrest and neuronal differentiation. Exposure to retinoic acid (RA), a differentiation agent in many cell types, causes an upregulation of neurotrophin receptor TrkB and the cyclin kinase inhibitor p21Cip1 at a transcriptional level. Full transcriptional activation of these two genes requires canonical E-box sequences found in the TrkB and p21Cip1 promoters. As reported for other E-box-regulated promoters, ectopic expression of E47 and E12 basic helix-loop-helix (bHLH) proteins enhances RA-dependent expression of TrkB and p21Cip1 , whereas the inhibitory HLH Id2 exerts opposite effects. In addition, ectopic expression of E47 and NeuroD, a neuronal bHLH protein, is able to activate TrkB transcription in the absence of RA. More importantly, we show that E47 and NeuroD proteins bind the TrkB and p21Cip1 promoter sequences in vivo. Since they establish a direct transcriptional link between a cell cycle inhibitor, p21Cip1 , and a neurotrophic receptor, TrkB, bHLH proteins would play an important role in coordinating key events of cell cycle arrest and neuronal differentiation.

scholarly journals Cell Cycle Arrest in G2/M Promotes Early Steps of Infection by Human Immunodeficiency Virus

2005 ◽  
Vol 79 (9) ◽  
pp. 5695-5704 ◽  
Author(s):  
Bettina Groschel ◽  
Frederic Bushman
Keyword(s):  
Cell Cycle ◽  
Human Immunodeficiency Virus ◽  
Hiv Infection ◽  
Cell Cycle Arrest ◽  
Lung Fibroblasts ◽  
Serum Starvation ◽  
Cycle Arrest ◽  
Immunodeficiency Virus ◽  
High Concentrations ◽  
Transformed Cell Lines

ABSTRACT We have identified four small molecules that boost transduction of cells by human immunodeficiency virus (HIV) and investigated their mechanism of action. These molecules include etoposide and camptothecin, which induce DNA damage by inhibiting religation of cleaved topoisomerase-DNA complexes, taxol, which interferes with the function of microtubules, and aphidicolin, which inhibits DNA polymerases. All four compounds arrest the cell cycle at G2/M, though in addition high concentrations of aphidicolin arrest in G1. We find that early events of HIV replication, including synthesis of late reverse transcription products, two-long terminal repeat circles, and integrated proviruses, were increased after treatment of cells with concentrations of each compound that arrested in G2/M. Stimulation was seen for both transformed cell lines (293T and HeLa cells) and primary cells (IMR90 lung fibroblasts). Arrest in G1 with high concentrations of aphidicolin boosted transduction, though not much as with lower concentrations that arrested in G2/M. Arrest of IMR90 cells in G1 by serum starvation and contact inhibition reduced transduction. Previously, the proteasome inhibitor MG132 was reported to increase HIV infection—here we investigated the effects of combinations of the cell cycle inhibitors with MG132 and obtained data suggesting that MG132 may also boost transduction by causing G2/M cell cycle arrest. These data document that cell cycle arrest in G2/M boosts the early steps of HIV infection and suggests methods for increasing transduction with HIV-based vectors.

scholarly journals Two Related Kinesins,klp5+andklp6+, Foster Microtubule Disassembly and Are Required for Meiosis in Fission Yeast

2001 ◽  
Vol 12 (12) ◽  
pp. 3919-3932 ◽  
Author(s):  
Robert R. West ◽  
Terra Malmstrom ◽  
Cynthia L. Troxell ◽  
J. Richard McIntosh
Keyword(s):  
Cell Cycle ◽  
Fission Yeast ◽  
Amino Terminal ◽  
Cellular Processes ◽  
Cycle Arrest ◽  
Microtubule Motor ◽  
Cytoplasmic Microtubules ◽  
High Concentrations ◽  
Kinesin Superfamily ◽  
Mitosis And Meiosis

The kinesin superfamily of microtubule motor proteins is important in many cellular processes, including mitosis and meiosis, vesicle transport, and the establishment and maintenance of cell polarity. We have characterized two related kinesins in fission yeast,klp5+andklp6+, that are amino-terminal motors of the KIP3 subfamily. Analysis of null mutants demonstrates that neither klp5+norklp6+, individually or together, is essential for vegetative growth, although these mutants have altered microtubule behavior. klp5Δ and klp6Δ are resistant to high concentrations of the microtubule poison thiabendazole and have abnormally long cytoplasmic microtubules that can curl around the ends of the cell. This phenotype is greatly enhanced in the cell cycle mutant cdc25–22, leading to a bent, asymmetric cell morphology as cells elongate during cell cycle arrest. Klp5p-GFP and Klp6p-GFP both localize to cytoplasmic microtubules throughout the cell cycle and to spindles in mitosis, but their localizations are not interdependent. During the meiotic phase of the life cycle, both of these kinesins are essential. Spore viability is low in homozygous crosses of either null mutant. Heterozygous crosses of klp5Δ with klp6Δ have an intermediate viability, suggesting cooperation between these proteins in meiosis.

Helicobacter pylori induces cell cycle arrest of T-lymphocytes

2005 ◽  
Vol 43 (05) ◽  
Author(s):  
M Gerhard ◽  
C Schmees ◽  
R Rad ◽  
P Voland ◽  
T Treptau ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Helicobacter Pylori ◽  
T Lymphocytes ◽  
Cell Cycle Arrest ◽  
Cycle Arrest
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