Abstract
Abstract: :
Purpose: To investigate the expression of A20, a known antiapoptotic gene and inhibitor of NFΚB, in the retinas of wild type mice and mice with a targeted deletion of the rhodopsin gene, and to examine the potential role of A20 as an inhibitor of retinal degeneration. Methods: Expression levels were quantified using both microarray analysis and relative quantitative RT PCR. Expression patterns of A20 in the mouse retina were examined by in situ hybridization using digoxygenin (DIG)–labeled riboprobes on frozen cryosections Results: A recent study carried out in our lab compared expression of 6000 transcripts from retinas of 4 month old wild type and rho–/– mice using microarrays. The gene encoding A20 showed the most significant (12.5 fold) down–regulation of all genes examined in rho–/– retinas, indicating possible high levels of expression in the photoreceptor cells relative to other retinal cell types. A subsequent microarray analysis of retinal RNA from wild type and rho–/– mice over 8 time points from 10 to 60 days both showed A20 expression to decline steadily over time, consistent with disease progression and photoreceptor degeneration. Data obtained using RT PCR confirmed these results, showing a similar change in the transcriptional profile of the gene. In situ hybridizations then determined the precise pattern of A20 expression in the mouse retina Conclusion: Our data indicates that A20 is expressed at relatively high levels in wild type mouse retinas, but that expression of the gene declines greatly over the course of the retinal degeneration in rhodopsin knockout mice. As A20 is a potent inhibitor of apoptosis, this provides the basis to investigate if overexpression of the gene in the retinas of mice lacking rhodopsin protects against photoreceptor death. Comercial Relationship: A.G.McKee, None; A.Kennan, None; N.McNally, None; P.F.Kenna, None; P.Humphries, None.
Keywords: apoptosis/cell death • retinal degenerations: cell biology • transgenics/knock–outs