Endogenous Elevation of Homocysteine Induces Retinal Neuron Death in the Cystathionine-b-Synthase Mutant Mice. Mus musculus

The effects of endogenous elevation of homocysteine on retinal gene expression were screened by microarray analysis, which was performed in triplicate (i.e., three different paired RNA samples) with RNA isolated from neural retinas of cbs+/- HM at 5-weeks after a methionine diet and age-matched wildtype mice. The microarray chips used in this study permitted the screening of 36,212 genes. Of particular interest were those genes in cbs+/- HM mice whose expression levels changed by at least a factor of 2 (increased or decreased expression) compared with the wild-type in each of the replicate experiments. Using these selection criteria, we identified 1219 genes. They were categorized into six functional groups: (1) proapoptosis, (2) antiapoptosis, (3) cell cycle, (4) antioxidant, (5) calcium signaling, and (6) axon growth/guidance, with the remaining genes with marked changes in expression placed in a miscellaneous group. After categorization, relevant genes were further narrowed by SAM analysis; q < 0.06 was considered significant. Overall design: Microarrays were performed in triplicate as biological repeats and reverse fluoro (i.e., three different paired RNA samples) with RNA isolated from neural retinas of cbs+/- HM at 5-weeks after a methionine diet and age-matched wildtype mice after a methionine diet.