Transcription profiling of mouse skeletal muscle to detect genes that regulate motor axon growth and differentiation

ABSTRACT: These experiments are designed to discover genes that are expressed selectively by synaptic nuclei in skeletal muscle with the particular goal of identifying genes that regulate motor axon growth and differentiation. We plan to isolate RNA from the dissected synaptic region of skeletal muscle and from the non-synaptic region of skeletal muscle and to identify the genes that are expressed at higher levels in the synaptic than non-synaptic region. Previously, we showed that motor axons fail to stop and differentiate in mice lacking MuSK, a receptor tyrosine kinase that is activated by motor neuron-derived Agrin. We hypothesize that MuSK activation normally leads to the production of a retrograde stop/differentiation signal that is encoded by a gene that is expressed preferentially in synaptic nuclei. In the absence of MuSK signaling, the retrograde signaling is not produced by synaptic nuclei, and consequently motor axons wander aimlessly over the muscle. We obtain 6 to 8 micrograms of total RNA from the dissected synaptic or non-synaptic region from a single P21 mouse diaphragm muscle. This is a standard procedure in the lab, and we have used these methods to analzye gene expression and to generate high-quality cDNA libraries. Because the synaptic zone is narrower in the left hemi-diaphragm, we will isolate RNA from this half of the diaphragm. In order to isolate sufficient RNA (5 micrograms from each sample), we will pool the synaptic and non-synaptic regions from two hemi-diaphragms. In order to reduce experimental variability, we wish to analzye expression in six samples: three samples of synaptic RNA and three samples of non-synaptic RNA. We will ship the isolated RNA samples to the Consortium in order to generate labeled cDNA, to screen Affymetrix mouse oligo arrays and to assist in the analysis. Several genes, including the subunits of the acetylcholine receptor, MuSK, acetylcholinesterase, and utrophin are known to be expressed preferentially in synaptic nuclei; thus, these genes serve as internal controls for the reliability and effectiveness of the screen. Most other genes, several of which we have analyzed in previous studies, including actin, GAPDH, runx1, nogoC, creatine kinase, etc. are expressed uniformly in skeletal muscle; thus, expression of these genes should be equally represented in synaptic and non-synaptic regions. Experiment Overall Design: as above

ORGANISM(S): Mus musculus

SUBMITTER: Elizabeth Salomon 

PROVIDER: E-GEOD-2873 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress