Short- and long-term mechanisms of tau regulation in PC12 cells

1995 ◽  
Vol 108 (8) ◽  
pp. 2857-2864 ◽  
Author(s):  
E. Sadot ◽  
J. Barg ◽  
D. Rasouly ◽  
P. Lazarovici ◽  
I. Ginzburg
Keyword(s):  
Nerve Growth Factor ◽  
Growth Factor ◽  
Pc12 Cells ◽  
Tau Protein ◽  
Immunoblot Analysis ◽  
Term Treatment ◽  
Mrna Levels ◽  
Short Term Treatment ◽  
Nerve Growth ◽  
Protein Levels

Induction by nerve growth factor of neurite outgrowth in PC12 cells is transcription-dependent and is associated with the accumulation of tau protein. It was recently shown that short-term treatment with staurosporine, a protein kinase alkaloid inhibitor, induced an elevation of tau protein levels and outgrowth of stable neurites. In this study, we analyzed the mechanism(s) by which nerve growth factor and staurosporine exert their effects on tau levels. We demonstrate that nerve growth factor affects tau mRNA stability, thus contributing to the observed increase in tau mRNA levels. On the other hand, tau mRNA levels were not affected by the treatment with staurosporine. We also demonstrate that the phosphorylation of tau protein was reduced after treatment of PC12 cells with nerve growth factor or staurosporine, as shown by immunoblot analysis using specific antibodies and alkaline phosphatase treatment. Thus, regulation of tau levels by nerve growth factor appears to be mediated by transcriptional, post-transcriptional and posttranslational steps, whereas the effect of staurosporine on tau levels may be attributed to its effect on the state of phosphorylation of the protein.

Effect of protein synthesis inhibitors on growth factor activation of c-fos, c-myc, and actin gene transcription

1986 ◽  
Vol 6 (4) ◽  
pp. 1050-1057
Author(s):  
M E Greenberg ◽  
A L Hermanowski ◽  
E B Ziff
Keyword(s):  
Protein Synthesis ◽  
Nerve Growth Factor ◽  
Growth Factor ◽  
Pc12 Cells ◽  
Gene Transcription ◽  
Actin Gene ◽  
Mrna Levels ◽  
Protein Synthesis Inhibitors ◽  
3T3 Cells ◽  
Nerve Growth

Stimulation of quiescent 3T3 cells with purified growth factors or of the pheochromocytoma cell line PC12 with nerve growth factor results in the rapid transient induction of c-fos, c-myc, and actin gene transcription (M.E. Greenberg and E.B. Ziff, Nature [London] 312:711-716; M.E. Greenberg, L.A. Greene, and E.B. Ziff, J. Biol. Chem. 26:14101-14110). We used protein synthesis inhibitors to investigate whether synthesis of new proteins plays a role in the rapid induction and subsequent repression of the transcription of these genes. Pretreatment of quiescent 3T3 cells with the inhibitor anisomycin before growth factor stimulation caused a superinduction of c-fos and c-myc mRNA levels upon growth factor addition. Nuclear runoff transcription analyses of 3T3 cells indicated that anisomycin potentiated c-fos, c-myc, and also actin expression at the transcriptional level, possibly by inhibiting transcriptional repression. Somewhat different results were obtained when PC12 cells were incubated with either anisomycin or cycloheximide. In PC12 cells protein synthesis inhibitors superinduced nerve growth factor activation of c-fos mRNA production but completely abolished the activation of c-myc. The results suggest that in PC12 cells c-fos transcription is activated by a protein-synthesis-independent mechanism, whereas c-myc stimulation requires new protein synthesis. The difference in the effect of anisomycin on growth factor activation of c-myc expression in 3T3 versus PC12 cells may be due to differential stringency of protein synthesis inhibition in the two cells or could reflect cell type differences in c-myc regulation.

Nerve growth factor (NGF) induces neuronal differentiation in neuroblastoma cells transfected with the NGF receptor cDNA

1990 ◽  
Vol 10 (9) ◽  
pp. 5015-5020
Author(s):  
H Matsushima ◽  
E Bogenmann
Keyword(s):  
Nerve Growth Factor ◽  
Growth Factor ◽  
Neuroblastoma Cell ◽  
Neuroblastoma Cells ◽  
Neuroblastoma Cell Line ◽  
Term Treatment ◽  
Short Term Treatment ◽  
Nerve Growth ◽  
Ngf Receptor ◽  
Long Term Treatment

Human nerve growth factor (NGF) receptor (NGFR) cDNA was transfected into a neuroblastoma cell line (HTLA 230) which does not express a functional NGF-NGFR signal transduction cascade. Short-term treatment of stably transfected cells (98-3) expressing membrane-bound NGF receptor molecules resulted in a cell cycle-dependent, transient expression of the c-fos gene upon treatment with NGF, suggesting the presence of functional high-affinity NGFR. Extensive outgrowth of neurites and cessation of DNA synthesis occurred in transfectants grown on an extracellular matrix after long-term treatment with NGF, suggesting terminal differentiation. Our data support the idea that introduction of a constitutively expressed NGFR cDNA into cells with neuronal background results in the assembly of a functional NGF-NGFR signal cascade in a permissive extracellular environment.

scholarly journals Effect of protein synthesis inhibitors on growth factor activation of c-fos, c-myc, and actin gene transcription.

1986 ◽  
Vol 6 (4) ◽  
pp. 1050-1057 ◽  
Author(s):  
M E Greenberg ◽  
A L Hermanowski ◽  
E B Ziff
Keyword(s):  
Protein Synthesis ◽  
Nerve Growth Factor ◽  
Growth Factor ◽  
Pc12 Cells ◽  
Gene Transcription ◽  
Actin Gene ◽  
Mrna Levels ◽  
Protein Synthesis Inhibitors ◽  
3T3 Cells ◽  
Nerve Growth

Stimulation of quiescent 3T3 cells with purified growth factors or of the pheochromocytoma cell line PC12 with nerve growth factor results in the rapid transient induction of c-fos, c-myc, and actin gene transcription (M.E. Greenberg and E.B. Ziff, Nature [London] 312:711-716; M.E. Greenberg, L.A. Greene, and E.B. Ziff, J. Biol. Chem. 26:14101-14110). We used protein synthesis inhibitors to investigate whether synthesis of new proteins plays a role in the rapid induction and subsequent repression of the transcription of these genes. Pretreatment of quiescent 3T3 cells with the inhibitor anisomycin before growth factor stimulation caused a superinduction of c-fos and c-myc mRNA levels upon growth factor addition. Nuclear runoff transcription analyses of 3T3 cells indicated that anisomycin potentiated c-fos, c-myc, and also actin expression at the transcriptional level, possibly by inhibiting transcriptional repression. Somewhat different results were obtained when PC12 cells were incubated with either anisomycin or cycloheximide. In PC12 cells protein synthesis inhibitors superinduced nerve growth factor activation of c-fos mRNA production but completely abolished the activation of c-myc. The results suggest that in PC12 cells c-fos transcription is activated by a protein-synthesis-independent mechanism, whereas c-myc stimulation requires new protein synthesis. The difference in the effect of anisomycin on growth factor activation of c-myc expression in 3T3 versus PC12 cells may be due to differential stringency of protein synthesis inhibition in the two cells or could reflect cell type differences in c-myc regulation.

scholarly journals Nerve growth factor (NGF) induces neuronal differentiation in neuroblastoma cells transfected with the NGF receptor cDNA.

1990 ◽  
Vol 10 (9) ◽  
pp. 5015-5020 ◽  
Author(s):  
H Matsushima ◽  
E Bogenmann
Keyword(s):  
Nerve Growth Factor ◽  
Growth Factor ◽  
Neuroblastoma Cell ◽  
Neuroblastoma Cells ◽  
Neuroblastoma Cell Line ◽  
Term Treatment ◽  
Short Term Treatment ◽  
Nerve Growth ◽  
Ngf Receptor ◽  
Long Term Treatment

Human nerve growth factor (NGF) receptor (NGFR) cDNA was transfected into a neuroblastoma cell line (HTLA 230) which does not express a functional NGF-NGFR signal transduction cascade. Short-term treatment of stably transfected cells (98-3) expressing membrane-bound NGF receptor molecules resulted in a cell cycle-dependent, transient expression of the c-fos gene upon treatment with NGF, suggesting the presence of functional high-affinity NGFR. Extensive outgrowth of neurites and cessation of DNA synthesis occurred in transfectants grown on an extracellular matrix after long-term treatment with NGF, suggesting terminal differentiation. Our data support the idea that introduction of a constitutively expressed NGFR cDNA into cells with neuronal background results in the assembly of a functional NGF-NGFR signal cascade in a permissive extracellular environment.

scholarly journals Regulation of microtubule protein levels during cellular morphogenesis in nerve growth factor-treated PC12 cells.

1988 ◽  
Vol 106 (5) ◽  
pp. 1583-1591 ◽  
Author(s):  
D Drubin ◽  
S Kobayashi ◽  
D Kellogg ◽  
M Kirschner
Keyword(s):  
Protein Synthesis ◽  
Nerve Growth Factor ◽  
Growth Factor ◽  
Pc12 Cells ◽  
Feedback Regulation ◽  
The State ◽  
Mrna Levels ◽  
Microtubule Depolymerization ◽  
Nerve Growth ◽  
Microtubule Polymerization

Nerve growth factor induces neurite process formation in pheochromacytoma (PC12) cells and causes the parallel increase in levels of the microtubule-associated proteins, tau and MAP1, as well as increases in tubulin levels. Mechanisms to insure balanced accumulation of microtubule proteins and make their levels highly responsive to nerve growth factor were investigated. The effects on tau, MAP1, and tubulin are due to changes in protein synthesis rates, which for tau and tubulin we could show are due in part to changes in the mRNA levels. Whereas tubulin shows feedback regulation to modulate synthesis up or down, tau protein synthesis is not affected in a straightforward way by microtubule polymerization and depolymerization. The degradation of tau, MAP1, and both tubulin polypeptides, however, are stimulated by microtubule depolymerization caused by colchicine, or nerve growth factor removal. Combined feedback on synthesis and stability make tubulin levels highly responsive to assembly states. In addition, the linkage of tau and MAP1 turnover with the state of microtubule polymerization amplifies any change in their rate of synthesis, since tau and MAP1 promote microtubule polymerization. This linkage lends itself to rapid changes in the state of the system in response to nerve growth factor.

scholarly journals Induction of neuron-specific tropomyosin mRNAs by nerve growth factor is dependent on morphological differentiation.

1993 ◽  
Vol 120 (1) ◽  
pp. 205-215 ◽  
Author(s):  
R P Weinberger ◽  
R C Henke ◽  
O Tolhurst ◽  
P L Jeffrey ◽  
P Gunning
Keyword(s):  
Nerve Growth Factor ◽  
Growth Factor ◽  
Pc12 Cells ◽  
Critical Role ◽  
Morphological Differentiation ◽  
Mrna Levels ◽  
Neuronal Phenotype ◽  
Nerve Growth ◽  
Cellular Expression

We have examined the expression of brain-specific tropomyosins during neuronal differentiation. Both TmBr-1 and TmBr-3 were shown to be neuron specific. TmBr-1 and TmBr-3 mRNA levels increased during the most active phase of neurite outgrowth in the developing rat cerebellum. In PC12 cells stimulated by nerve growth factor (NGF) to differentiate to the neuronal phenotype, TmBr-1 and TmBr-3 levels increased with an increasing degree of morphological differentiation. Induction of TmBr-1 and TmBr-3 expression only occurred under conditions where PC12 cells were permitted to extend neurites. NGF was unable to maintain levels of TmBr-1 and TmBr-3 with the loss of neuronal phenotype by resuspension of differentiated PC12 cells. The unique cellular expression and regulation in vivo and in vitro of TmBr-1 and TmBr-3 strongly suggests a critical role of these tropomyosins in neuronal microfilament function. The findings reveal that the induction and maintenance of the neuronal tropomyosins is dependent on morphological differentiation and the maintenance of the neuronal phenotype.

Sign in / Sign up

Export Citation Format

Share Document