NOVEL GENE TRANSCRIPTS EXPRESSED IN DEVELOPING SENSORY NEOCORTEX IN THE MOUSE
1. Picower Center for Learning and Memory, 2. Brain and Cognitive Sciences, 3. Biology, MIT, Cambridge, MA, USA
The connective patterns of mammalian neocortical areas play a fundamental role in defining their characteristic functions. The mechanisms that underlie the development of these connectivity patterns are not well understood however. We are interested in identifying novel genes and gene products that may be involved in the development of neocortical areas. To do this we used a high-density DNA microarray to detect expressed sequence tags (ESTs) that are differentially expressed between the somatosensory and visual cortices in early postnatal mice. Total RNA was extracted from tissue removed from the presumptive somatosensory and visual cortices of postnatal day (P)0-1 Black 6 mice. Biotinylated cRNA was then produced via cDNA synthesis and in vitro transcription reactions. Four separately prepared samples from each area were hybridized to a microarray containing multiple oligos corresponding to 12,000 ESTs. In analysis of the results, we identified ESTs that fulfilled 3 criteria: apppropriate absence/presence call, difference call, and had a fold change greater than 2 for at least 3 of the 4 pairs of samples examined. We found 19 ESTs in which these criteria were met, 10 of which are more highly expressed in the visual cortex than in the somatosensory cortex, and 9 of which are more highly expressed in the somatosensory cortex than in the visual cortex. The differential expression of many of these genes between the cortical regions has been confirmed by semi-quantitative PCR. We are currently examining the temporal and areal expression patterns of the genes by in situ hybridization.
Supported by: NIH EY11512 and NS39022 to MS and MH58880 and NS32925 to ST.