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Apoptotic gene expression changes in an IRBP‐deficient mouse model of retinal degeneration at 21–27 days of age
Author(s) -
Donmoyer Christine M,
Giles Jessica,
Homa Linnea
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.727.2
Subject(s) - apoptosis , biology , retinal degeneration , microbiology and biotechnology , gene expression , tunel assay , messenger rna , gene , retinal , genetics , biochemistry
In models of retinal degeneration, damage may occur to photoreceptors or retinal pigment epithelial cells, and cellular damage triggers apoptosis. In mice deficient in interphotoreceptor retinoid‐binding protein (IRBP −/− ), approx. 40% of photoreceptors are lost by 30 days of age, resulting in partial blindness. TUNEL staining suggests that apoptosis peaks at postnatal day 25 in the IRBP −/− . We asked which genes involved in apoptosis were responsible for photoreceptor loss. IRBP −/− mice, postnatal day 21 through 27 (P21–P27), were sacrificed, and retinas from n=4 mice were pooled. Total RNA from pooled retinas was isolated and used to synthesize cDNA. mRNA abundance was analyzed by quantitative PCR with SYBR green and primers for apoptotic genes; beta‐actin was used as a reference gene. The age with the lowest relative gene expression (cycle threshold, ΔC t ) was used as a control (set to 1), and other ages were compared to it (ΔΔC t ). The expression ratio (2 ΔΔCt ) was then calculated. Pro‐apoptotic genes bax, TRADD, ASK‐1, and bnip3l and anti‐apoptotic gene bcl‐2 were studied. mRNA for ASK‐1, bax and bnip31 were most abundant at P23 in IRBP −/− mice, with bax having 300‐fold greater expression than at P21. Anti‐apoptotic bcl‐2 mRNA was also more abundant at P23 (40‐fold more than P21) in IRBP −/− mice, while TRADD expression was highest at P27. In summary, with highest expression at P23, the three pro‐apoptotic genes may be contributing to the apoptotic signal in IRBP‐deficient retinas. Future work can distinguish the apoptotic pathway involved in photoreceptor loss in this mouse model.