Up- (green) and down (red) -regulation of genes after initiation of myelination with ascorbate in Schwann cell/ dorsal root ganglion co-cultures.

The development of myelinated axons in the PNS is mediated by complex Schwann cell-neuronal interactions. Key molecules in the pathways related to Schwann cell development, myelin biogenesis, and neuronal regulation have been studied extensively by members of the Strickland Laboratory as well as at other institutions. These studies have generally employed single gene knock-out in mice to elucidate the role of the relevant protein in these pathways. While this research has yielded valuable information, the complexity of biological network interactions within and between Schwann cells and neuronal cells remains unclear.

In the DRG co-culture system introduced above, DRGs containing primary Schwann cells and neurons are dissected from E13.5 mice homozygous fLAMγ1 allele (F/F). The resulting Schwann cell/ neuronal cultures undergo myelination in a controlled, timed manner. This system is ideal for the study of complex network interactions between these two cell types by taking advantage of temporally-dependent microarray data. RNA will be obtained from the myelinating co-cultures over time, so the resultant changes in gene expression profile will include information about Schwann cell/ neuronal interactions.

Members of the Strickland Laboratory have obtained RNA samples from the onset of myelination, which is triggered by the addition of ascorbic acid, until myelination is readily visible by a fluorescent stain for myelin after eight days. Microarrays performed in triplicate at each time point, each including >20,000 genes, will be mined for information about genetic interactions. Furthermore, the use adeno-virus Cre infected F/F co-cultures will allow the role of laminin to be examined in this context. Previous mathematical methods have provided correlation or cluster analyses; however, lab members intend to infer the networks of genetic interactions from the temporal gene expression data in the process of myelination. The approach biomedical fellow Jot Dhadialla and Sidney Strickland will employ, termed “entropy maximization,” has been valuable for modeling equilibrium situations as resting yeast metabolic states as well as non-equilibrium situations such as neural networks and global climates.

::: Back to Top     ::: Back to List of Projects