Laser capture microdissection and cDNA array analysis for identification of mouse KIAA/FLJ genes differentially expressed in the embryonic dorsal spinal cord.

During early development, centrally projecting dorsal root ganglion (DRG) neurons extend their axons toward the dorsal spinal cord. We previously reported that this projection is achieved by dorsal spinal cord-derived chemoattraction. However, the molecular nature of the chemotrophic cue is not yet fully understood. To identify novel genes differentially expressed in the dorsal spinal cord in the embryonic day 10.5 mouse, we used the Kazusa cDNA array system comprising approximately 1700 mouse KIAA/FLJ (mKIAA/mFLJ) cDNA clones and laser capture microdissection (LCM) in combination with PCR-based cDNA amplification. We observed that a certain population of genes showed significantly increased expression in the dorsal spinal cord. In situ hybridization analysis verified the expression of mRNAs of 6 genes (Hip1r, Nav2, Fstl5, Cacna1h, Bcr, and Bmper) in the cells that constitute the dorsal spinal cord. The dorsal spinal cord-specific genes identified in this study provide a basis for studying the molecular nature of the neural development including the axonal guidance of DRG neurons. These results also demonstrate that the combined use of LCM coupled with the Kazusa cDNA array technology will be useful for the identification of large proteins expressed in the restricted small regions of embryos.