Abstract
Abstract: :
Purpose: To characterize the gene expression pattern in a mutant mouse line with abnormal retinal ribbon synapses and to identify the underlying molecular defect. Methods: Eye RNA from 6 mice (3 mutants and 3 wild types), was analysed separately on individual Affymetrix Mouse Genome U74Av2 microarrays. Altered transcript levels of selected candidate genes were confirmed by real–time PCR for 10 animals (5 pairs). Mutation screening in candidate genes was performed by direct sequencing of the open reading frames . Results: The array contained oligonucleotide probes representing transcripts from 12'000 genes. In wild type eyes, 40.2% of the genes showed expression, while in mutant eyes only 30.6% were detected. In total, 105 transcripts revealed statistically significant differential expression. We obtained altered relative transcript levels in eyes of affected mice for genes involved in the phototransduction cascade (Rho: 26%, Pdc: 37%, Pde: 50%); synaptic exocytosis machinery (Snap25: 49%, Stx4a: 73%, Syn1b: 77%, Vamp1: 232%); synaptic signal tranduction (Kcna6: 54%, Kcna5: 58%, Gat3: 69%); or synaptic adhesion (Muc10: 29%, Reln: 49%, SemE: 140%, Ninj2: 153%). For mutation detection, the coding region of 30 candidate genes was sequenced. So far however, no pathogenic sequence variant has been identified. Conclusions: The expression profiling experiments deciphered important information concerning alterations in gene expression of mutant eyes and enabled rapid selection of candidate genes for further analysis.
Keywords: gene microarray • synapse • transcription