scholarly journals Conditional Genetic Transsynaptic Tracing in the Embryonic Mouse Brain

10.3791/52487 ◽  
2014 ◽  
Author(s):  
Devesh Kumar ◽  
Ulrich Boehm
Keyword(s):  
Mouse Brain ◽  
Embryonic Mouse ◽  
Transsynaptic Tracing

Myf5 is a novel early axonal marker in the mouse brain and is subjected to post-transcriptional regulation in neurons

Development ◽  
2000 ◽  
Vol 127 (2) ◽  
pp. 319-331 ◽  
Author(s):  
P. Daubas ◽  
S. Tajbakhsh ◽  
J. Hadchouel ◽  
M. Primig ◽  
M. Buckingham
Keyword(s):  
Transcription Factor ◽  
Mouse Brain ◽  
Mrna Translation ◽  
Adult Brain ◽  
Protein Accumulation ◽  
Embryonic Mouse ◽  
Signalling Molecules ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
The Brain

Myf5 is a key basic Helix-Loop-Helix transcription factor capable of converting many non-muscle cells into muscle. Together with MyoD it is essential for initiating the skeletal muscle programme in the embryo. We previously identified unexpected restricted domains of Myf5 transcription in the embryonic mouse brain, first revealed by Myf5-nlacZ(+/)(−) embryos (Tajbakhsh, S. and Buckingham, M. (1995) Development 121, 4077–4083). We have now further characterized these Myf5 expressing neurons. Retrograde labeling with diI, and the use of a transgenic mouse line expressing lacZ under the control of Myf5 regulatory sequences, show that Myf5 transcription provides a novel axonal marker of the medial longitudinal fasciculus (mlf) and the mammillotegmental tract (mtt), the earliest longitudinal tracts to be established in the embryonic mouse brain. Tracts projecting caudally from the developing olfactory system are also labelled. nlacZ and lacZ expression persist in the adult brain, in a few ventral domains such as the mammillary bodies of the hypothalamus and the interpeduncular nucleus, potentially derived from the embryonic structures where the Myf5 gene is transcribed. To investigate the role of Myf5 in the brain, we monitored Myf5 protein accumulation by immunofluorescence and immunoblotting in neurons transcribing the gene. Although Myf5 was detected in muscle myotomal cells, it was absent in neurons. This would account for the lack of myogenic conversion in brain structures and the absence of a neural phenotype in homozygous null mutants. RT-PCR experiments show that the splicing of Myf5 primary transcripts occurs correctly in neurons, suggesting that the lack of Myf5 protein accumulation is due to regulation at the level of mRNA translation or protein stability. In the embryonic neuroepithelium, Myf5 is transcribed in differentiated neurons after the expression of neural basic Helix-Loop-Helix transcription factors. The signalling molecules Wnt1 and Sonic hedgehog, implicated in the activation of Myf5 in myogenic progenitor cells in the somite, are also produced in the viscinity of the Myf5 expression domain in the mesencephalon. We show that cells expressing Wnt1 can activate neuronal Myf5-nlacZ gene expression in dissected head explants isolated from E9.5 embryos. Furthermore, the gene encoding the basic Helix-Loop-Helix transcription factor mSim1 is expressed in adjacent cells in both the somite and the brain, suggesting that signalling molecules necessary for the activation of mSim1 as well as Myf5 are present at these different sites in the embryo. This phenomenon may be widespread and it remains to be seen how many other potentially potent regulatory genes, in addition to Myf5, when activated do not accumulate protein at inappropriate sites in the embryo.

Inhibition of transient potassium current in cultured and acutely dissociated mouse hippocampal neurons by GABAA receptor activation

1996 ◽  
Vol 76 (2) ◽  
pp. 816-824
Author(s):  
R. L. Wu ◽  
M. E. Barish
Keyword(s):  
Mouse Brain ◽  
Hippocampal Neurons ◽  
Potassium Current ◽  
Receptor Activation ◽  
Gabab Receptors ◽  
Cell Swelling ◽  
Cultured Neurons ◽  
Embryonic Mouse ◽  
Voltage Gated ◽  
A Current

1. The regulation of A-current, one of several transient voltage-gated potassium currents, was studied using whole cell gigaohm seal voltage-clamp techniques on hippocampal pyramidal neurons that were either acutely dissociated from postnatal mouse brain or isolated from embryonic mouse brain and grown in dissociated culture. These neurons also express gamma-aminobutyric acid-A (GABAA) receptors, the activation of which can, under some circumstances, depolarize immature neurons and the dendrites of more mature neurons. 2. Application of GABA (50 microM) reduced the amplitude of A-current when potassium current amplitude was measured during a period of slow and incomplete desensitization of IGABA. A-current was reduced to 67 +/- 9% of control (mean +/- SD, n - 14) in acutely dissociated neurons, and to 64 +/- 11% of control (n = 15) in cultured neurons. Similar A-current reductions were seen in large outside-out membrane patches pulled from somata of cultured neurons, an observation suggesting that imperfect control of membrane voltage was not responsible for A-current inhibition. 3. A-current inhibition exhibited the sensitivity expected of a GABAA-sensitive process. It was mimicked by muscimol and blocked by bicuculline, picrotoxin, and reduction of [Cl-] in the external solution. Baclophen and phaclophen, effective as agonist and antagonist on GABAB receptors, did not affect A-currents or their inhibition. Reduction in extracellular osmolarity (to increase cell swelling as might occur with Cl- entry), or removal of external HCO3- (which might flow inward through GABAA channels and cause local external acidification), did not affect A-current or its inhibition. The mechanisms of inhibition is not clear at present. 4. We suggest that reduced A-current may favor GABA-induced depolarization and consequent activation of voltage-gated calcium channels.

scholarly journals A chronological expression profile of gene activity during embryonic mouse brain development

2013 ◽  
Vol 24 (11-12) ◽  
pp. 459-472 ◽  
Author(s):  
P. Goggolidou ◽  
S. Soneji ◽  
N. Powles-Glover ◽  
D. Williams ◽  
S. Sethi ◽  
...  
Keyword(s):  
Brain Development ◽  
Mouse Brain ◽  
Expression Profile ◽  
Gene Activity ◽  
Embryonic Mouse ◽  
Mouse Brain Development

scholarly journals Selective neuronal toxicity of cocaine in embryonic mouse brain cocultures.

1995 ◽  
Vol 92 (24) ◽  
pp. 11029-11033 ◽  
Author(s):  
M. C. Nassogne ◽  
P. Evrard ◽  
P. J. Courtoy
Keyword(s):  
Mouse Brain ◽  
Embryonic Mouse ◽  
Neuronal Toxicity
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