Project description:To investigate the participation of deafness genes in the genetic program of the superior olivary complex (SOC), a prominent auditory brainstem center, we performed a comparative genome-wide microarray based gene expression analysis of the rat SOC and the rat brain at postnatal days (P) P4 and P25. Data were validated by qRT-PCR. Statistical analyses revealed 912 oligos up-regulated in the SOC at P4 and 1609 at P25. A total of 453 oligos were up-regulated in the SOC at both developmental stages. Subsequently, a list of 138 transcripts associated with hearing-impairment was extracted from publically available databases and literature. 26 of these transcripts were present in SOC-related gene signature lists, whereas only 11 were present in brain-related gene signature lists. Furthermore, in all 3 SOC-related gene signature lists, transcripts associated with hearing impairment were significantly enriched. Finally, there was a tendency of the SOC-related genes to map to human deafness loci with unknown etiology. Altogether, our study identified a tight genetic link between the SOC-related genetic program and deafness genes.
Project description:To investigate the participation of deafness genes in the genetic program of the superior olivary complex (SOC), a prominent auditory brainstem center, we performed a comparative genome-wide microarray based gene expression analysis of the rat SOC and the rat brain at postnatal days (P) P4 and P25. Data were validated by qRT-PCR. Statistical analyses revealed 912 oligos up-regulated in the SOC at P4 and 1609 at P25. A total of 453 oligos were up-regulated in the SOC at both developmental stages. Subsequently, a list of 138 transcripts associated with hearing-impairment was extracted from publically available databases and literature. 26 of these transcripts were present in SOC-related gene signature lists, whereas only 11 were present in brain-related gene signature lists. Furthermore, in all 3 SOC-related gene signature lists, transcripts associated with hearing impairment were significantly enriched. Finally, there was a tendency of the SOC-related genes to map to human deafness loci with unknown etiology. Altogether, our study identified a tight genetic link between the SOC-related genetic program and deafness genes. The genome wide expression during the postnatal development of the SOC and the brain was investigated at two different time points: at postnatal (P) day 4 (before hearing onset) and at P25 (after hearing onset). Samples were hybridized onto two color platforms. At least 6 up to nine biological replicates per sample were performed.
Project description:Oligodendrocytes undergo extensive changes as they differentiate from progenitors into myelinating cells. To better understand the; molecular mechanisms underlying this transformation, we performed a comparative analysis using gene expression profiling of A2B5+; oligodendrocyte progenitors and O4+ oligodendrocytes. Cells were sort-purified ex vivo from postnatal rat brain using flow cytometry. Using Affymetrix microarrays, 1707 transcripts were identified with a more than twofold increase in expression inO4+oligodendrocytes. Many genes required for oligodendrocyte differentiation were upregulated in O4+ oligodendrocytes, including numerous genes encoding; myelin proteins. Transcriptional changes included genes required for cell adhesion, actin cytoskeleton regulation, and fatty acid and; cholesterol biosynthesis. At the O4+ stage, there was an increase in expression of a novel proline-rich transmembrane protein (Prmp). Localized to the plasma membrane, Prmp displays adhesive properties that may be important for linking the extracellular matrix to the; actin cytoskeleton. Together, our results highlight the usefulness of this discovery-driven experimental strategy to identify genes relevant; to oligodendrocyte differentiation and myelination. Experiment Overall Design: Whole brain dissociates were prepared from one litter of 10 male postnatal day 7 rat pups for each of the 5 A2B5 bioligcal replicates and the 4 O4+ bioligical replicates. Total RNA was extracted from single A2B5+ and single O4+ cells sorted directly from postnatal day7 rat whole brain dissociates using flow cytometry.