View Project Tourtellotte-5R01NS040748-03-2

Project Summary
Status:	Public
Publications:	1 Published 1 In Preparation
Project Detail		Data Detail
Platform:	Affymetrix	MIAME Areas	Compliance
Species:	Mouse	Array Design Detail	true
Organ/Tissue Type:	spinal cord	Experiment Detail	false
Organ Region:	spinal cord	Sample Detail	true
Cell Type:	fusimotor neurons	Hybridization Detail	false
Study Type:	subclassification	Measurement Detail	false
Disease/Condition:	sensory ataxia
Replicates:	2
Expected Samples:

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Investigator Contact Detail
Name	Warren G Tourtellotte
Street Address:	303 E. Chicago Ave.
City, State/Province:	Chicago , IL
Zip/Postal Code:	60611
Country:	United States
Work Phone:	312-503-2415
Fax:	312-503-2459
E-mail:	warren@northwestern.edu

Proposal Detail

Grant:

5R01NS040748-03

Status:

Public

Service Type:

Start to Finish Profiling

IACUC:

2003-0054

IACUC date:

2003-12-05

Study Relevance:

Egr3 is a zinc-finger transcription factor involved in growth and development. Egr3-deficient mice have severe sensory ataxia due to failed development of muscle spindle stretch receptors. Sensory and motor neurons that normally innervate spindles are absent in Egr3-deficient mice, presumably as a secondary consequence to the loss of trophic signals produced by spindles during development that are required for innervation and neuron survival. The molecular mechanisms involving motor neuron fate specification, target derived growth factor dependencies, and specification of target innervation have been difficult to study since select markers for functionally specific motor neurons are very poorly characterized. A more thorough understanding of the molecular mediators of motor neuron biology will be important to evaluate the efficacy of new strategies devised to thwart neuron death that occurs in a variety of human motor neuronopathies and neuropathies.

Hypothesis:

We hypothesize that fusimotor neurons can be distinguished in the spinal cord by characterizing fusimotor neuron specific gene expression. Once fusimotor neuron specific genes are identified, they will be used as markers to identify fusimotor neurons in complex neuroglial cell populations in vivo and in vitro. We hypothesize that by characterizing fusimotor neuron specific genes, unique marker molecules will be identified for in vivo and in vitro study of this functionally distinct and important motor neuron subtype. Moreover, we hypothesize that many of the genes that are specifically expressed by fusimotor neurons will be involved in mechanisms related to their fate specification, target innervation and growth factor dependent biology.

Specific Aim:

To identify genes specifically expressed by spinal cord fusimotor neurons: Many motor neuron specific genes have been described over the years. However, none have been described that distinguish fusimotor neurons from skeletomotor neurons despite the fact that they have distinct muscle targets (muscle spindle stretch receptors) and comprise 25-30% of the spinal motor neuron populations. Since these motor neurons have remarkably different target innervation and function, we hypothesize that they express genes that establish their specific phenotypes during development.

Experimental Procedure and Design:

We will use the Affymetrix microarray platform to identify genes that are specifically expressed by fusimotor neurons in mouse spinal cord. The differential expression analysis will be performed on microdissected segments of spinal cord (L3-L5) from wild type and Egr3-deficient mice. Postnatal Egr3-deficient mice lack muscle spindles and fusimotor neurons in their spinal cords. By comparing gene expression from microdissected segments of spinal cord (L3-L5) between wild type and Egr3-deficient mice, we hypothesize that fusimotor neuron selective genes can be identified. We will microdissect L3-L5 segments of spinal cord using precise anatomical landmarks to ensure that comparable spinal cord regions are anlayzed from each animal. For each microarray experiment, total RNA will be extracted from L3-L5 cords (approximately 2 mm length of spinal cord). The integrity of each RNA sample will be verified by gel electrophoresis. The intact RNA samples from mice of similar genotype will be pooled from three (3) 27-day old animals. The intact cord dissection is easier in young animals (eg: 27-day old) and the phenotype is known to exist at this developmental stage. The RNA from each animal of a similar genotype will be pooled into a single sample to minimize false positive gene calls that may represent genes related to the specific state of vigilance of a particular animal at the time of sacrifice (eg: activity dependent genes). Thus, each of the two RNA samples to be analyzed for a particular microarray experiment will represent RNA from three (3) spinal cords of each genotype. RNA amplification for probe synthesis should not be necessary since we will provide 7 ug of intact pooled total RNA for each sample. For statistical analysis, the experiment will be performed twice. Since the RNA samples are precious, they will be provided to the Array Consortium in two shipments with each of the experiments performed independently.

Experimental Factors:

Conditions that are tested in the experiment. At least one is required. Experimental factors are the independent variables in the experiment.


Experimental Factors is empty.

Project Samples

Samples associated with this project.

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Name	Description	Bio-Source	Extracts
RNA450	Pooled total RNA from (3) P...	RNA450	1
RNA 500	Pooled total RNA from (3) P...	RNA 500	1
RNA 499	Pooled total RNA from (3) P...	RNA 499	1
RNA 449	Pooled total RNA from (3) P...	RNA 449	1
RNA 650	Pooled total RNA from (3) P...	RNA 650	1
RNA 649	Pooled total RNA from (3) P...	RNA 649	1

Project Hybridizations

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Name	Array	Labeled Extract	Hybridization Protocol
Hybridization3	Mouse Expression Set 430 Array MOE430A_1	RNA450_e1_le1	Affymetrix
Hybridization4	Mouse Expression Set 430 Array MOE430A_2	RNA 500_e1_le1	Affymetrix
Hybridization5	Mouse Expression Set 430 Array MOE430A_3	RNA 499_e1_le1	Affymetrix
Mouse Expression Set 430 Array MOE430B_1_hyb	Mouse Expression Set 430 Array MOE430B_1	RNA450_e1_le2	Affymetrix
Mouse Expression Set 430 Array MOE430B_2_hyb	Mouse Expression Set 430 Array MOE430B_2	RNA 500_e1_le2	Affymetrix
Mouse Expression Set 430 Array MOE430B_3_hyb	Mouse Expression Set 430 Array MOE430B_3	RNA 499_e1_le2	Affymetrix
Mouse Expression Set 430 Array MOE430A_4_hyb	Mouse Expression Set 430 Array MOE430A_4	Sample4_e1_le1
Mouse Expression Set 430 Array MOE430B_4_hyb	Mouse Expression Set 430 Array MOE430B_4	Sample4_e1_le2

Project Reference Files

File Name	Size
NINDS-TMN-Egr3deficientFN-1aMOEA.CEL	4.83 Mb
NINDS-TMN-Egr3deficientFN-1aMOEA.CHP	4.86 Mb
NINDS-TMN-Egr3deficientFN-1aMOEA.DAT	57.13 Mb
NINDS-TMN-Egr3deficientFN-1aMOEB.CEL	4.83 Mb
NINDS-TMN-Egr3deficientFN-1aMOEB.CHP	4.83 Mb
NINDS-TMN-Egr3deficientFN-1aMOEB.DAT	57.11 Mb
NINDS-TMN-Egr3deficientFN-2aMOEA.CEL	11.44 Mb
NINDS-TMN-Egr3deficientFN-2aMOEA.CHP	13.87 Mb
NINDS-TMN-Egr3deficientFN-2aMOEA.dat	56.82 Mb
NINDS-TMN-Egr3deficientFN-2aMOEB.CEL	11.37 Mb
NINDS-TMN-Egr3deficientFN-2aMOEB.CHP	13.80 Mb
NINDS-TMN-Egr3deficientFN-2aMOEB.DAT	56.86 Mb
NINDS-TMN-wtFN-1aMOEA.CEL	11.54 Mb
NINDS-TMN-wtFN-1aMOEA.CHP	13.86 Mb
NINDS-TMN-wtFN-1aMOEA.DAT	56.25 Mb
NINDS-TMN-wtFN-1aMOEB.CEL	11.49 Mb
NINDS-TMN-wtFN-1aMOEB.CHP	13.79 Mb
NINDS-TMN-wtFN-1aMOEB.DAT	56.79 Mb
NINDS-TMN-wtFN-2aMOEA.CEL	11.47 Mb
NINDS-TMN-wtFN-2aMOEA.CHP	13.87 Mb
NINDS-TMN-wtFN-2aMOEA.DAT	56.59 Mb
NINDS-TMN-wtFN-2aMOEB.CEL	11.35 Mb
NINDS-TMN-wtFN-2aMOEB.CHP	13.80 Mb
NINDS-TMN-wtFN-2aMOEB.DAT	57.48 Mb
Pivot RNA649 WT.txt	6.17 Mb
Pivot RNA650 KO.txt	6.17 Mb
Signal Values all four arrays MOEA.TXT	6.44 Mb
Signal Values all four arrays MOEB.TXT	5.35 Mb
Tourtellotte RNA649 WT.CEL	12.32 Mb
Tourtellotte RNA650 KO.CEL	12.38 Mb

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