Elevation of RNA-binding protein CUGBP1 is an early event in an inducible heart-specific mouse model of myotonic dystrophy
J. Clin. Invest. Guey-Shin Wang, et al. 117:2802 doi:10.1172/JCI32308 [Go to this article.]

Figure 5
CUGBP1 and CUGBP2 protein steady-state levels increase in cardiac tissue expressing EpA960(R) mRNA. (A) Western blot analysis demonstrated elevated CUGBP1 and CUGBP2 protein expression in cardiac tissues expressing EpA960(R) mRNA (line EpA960/MCM 1323) 1 week following tamoxifen administration compared with tamoxifen-treated MCM littermates. An additional CUGBP2 band, possibly a splice variant, was expressed in some hearts expressing EpA960(R) mRNA. GAPDH was used as loading control. (B) Expression of CELF proteins remained unchanged in cardiac tissues expressing EpA0(R) mRNA (line 4294) 1 week following tamoxifen administration. (C) Nuclei expressing EpA960(R) mRNA foci exhibited elevated CUGBP1 protein expression, as shown by immunofluorescence staining.Arrowheads indicate nuclei containing RNA foci. (D) Higher magnification showed nuclei containing RNA foci also exhibited higher levels of CUGBP1. (E) Endogenous expression of CUGBP1 (arrowheads) in MCM mice given tamoxifen remained low. Nonspecific background in the cytoplasm was the result of mouse IgG. Nuclear CUGBP1 in cells expressing EpA0(R) mRNA (line 4294) remained low (F), as did nuclear CUGBP1 in MCM mice (E), 1 month following tamoxifen administration. (G) Nuclei containing EpA960(R) mRNA foci exhibited elevated expression of CUGBP2 protein. Arrowheads indicate nuclei containing RNA foci. (H) CUGBP2 expression (arrowheads) was low in tamoxifen-treated MCM hearts, with some areas of nonspecific staining in the cytoplasm. (I) Expression of CUGBP1 in the mouse heart at postnatal day 2. Images in E–I were taken using the same exposure time. Original magnification, ×40 (C and E–I); ×63 (D).