AIM: To identify the genes that were differentially expressed in the retina of rds mouse during the development of retinitis pigmentosa.METHODS: mRNA differential display method was used to compare and analyze mRNA samples prepared from the retina of rds mouse and normal mouse on postnatal day 25(P25). Differentially expressed fragments were cloned, sequenced and compared with GenBank database by BLASTN. Expression difference was further investigated by gene-specific primer RT-PCR.RESULTS: Obvious difference in gene expression occurred between rds mouse and normal mouse. One fragment, clone No.5, shared 91% homology with rat NADH-cytochrome b5 reductase (b5R) cDNA. Thus, it was identified as mouse b5R cDNA. Gene-specific RT-PCR confirmed that b5R mRNA level was increased in the retina of rds mouse compared with normal mouse on postnatal day 12, 25 and 37, respectively.CONCLUSION: Certain oxidative factors may up-regulate the expression of b5R resulting in large consumption of NADH and production of NAD +, through which apoptotic retinal cell death was enhanced.

Objective　 To clone the differentially expressed genes in the retina of rds mouse (the animal model of congenital retinitis pigmentosa) during the disease development. Methods　 The retinal mRNA of rds mouse during the development of retinitis pigmentosa was analyzed by the mRNA differential display. The differentilly expressed mRNA fragments were cloned and sequenced. Results There was obvious difference of gene expression between rds mouse and the control during the development of retinitis pigmentosa. Five differentially expressed bands were cloned and sequenced. One of those had 86% identity (132/154) with the sequence of the human cDNA DKFZp434D1227 from adult testis in GenBank, which was submitted lately (15-Oct-1999) and without much information. The other had lower identity with the sequeces in GenBank. A highly expressed clone in the rds mouse on postnatal day 25 had the same length as another clone in the normal on postnatal day 37, which was not expressed in the rds mouse on day 37. The sequences of the two clones were identical in all but two base pairs. Conclusion　 These results indicate that there are a lot of novel differentially expressed genes in the chronic processing diseases, such as retinitis pigmentosa.