The expression data from mandibular arch and tongue primordia in mouse embryos.

The mouse hypoglossal nerve originates from the occipital motor nuclei and projects a long distance, reaching the vicinity of the tongue primordia, the lateral lingual swelling, at E11.5. However, the details of how the hypoglossal nerve correctly projects to the primordia are not well understood. To investigate the molecular basis of hypoglossal nerve elongation, we employed cDNA microarray technology and screened for candidate genes involved in the axon guidance event. Tissues were dissected and pooled together in a single tube for microarray analysis. The following were collected into single tubes: E9.5 median mandibular arches (E9.5-MMA; 12 embryos/tube), E11.5 lateral lingual swellings (E11.5-LLS; 4 embryos/tube), E11.5 lateral mandibular arches (E11.5-LMA; 4 embryos/tube) and E14.5 median tongue (E14.5-T; 4 embryos/tube). Each of these regions were regarded as an independent tissue unit. We applied the ROKU method, an algorithm that can detect tissue-specific genes by comparing expression patters across different time periods and tissue regions.