WT vs Hypomethylated DRG Gene Expression

Although DNA methylation plays a critical role in the development and function of mammalian central nervous system (CNS), its role in peripheral neurons has not been elucidated. To address this issue, we produced conditional knockout mice (CKO) specifically deleting the gene for maintenance DNA methyltransferase 1 (Dnmt1) during the development of neural crest cells. Despite global hypomethylation in the embryonic dorsal root ganglion (DRG) of the CKO mice, the number of sensory neurons was relatively unaffected. However, expression of many genes required for sensory neuron development was altered in embryonic mutant DRG, including down-regulation of Runx1 and TrkA genes as well as up-regulation of Id1 and Dtx1, two negative regulators for neurogenesis. Accompanied with the downregulation of an NGF receptor TrkA, the peripheral axonal projection and the branching of sensory neurons were impaired. Furthermore, the expression of the neuropeptide Galanin and several vanilloid receptors such as TrpV1 and TrpM8 were not detected in the DRG of the CKO mice during late embryonic and neonatal stages, suggesting that DNA methylation regulates the differentiation program for a subset of nociceptive sensory neurons. Taken together, our findings suggest that through transcriptional regulation of key developmental genes in sensory neurons, DNA methylation play a key role in the control of the axonal projection and fate specification of peripheral sensory neurons. We compared gene expression patterns in Wildtype and DNA methylation deficient (Wnt1-cre; Dnmt1 mutant) mouse dorsal cortex. We performed 4 replicates using different each individual mouse strain. The Sample GSM565172 table is the average log ratio for the 4 replicatesArrays were performed.