Elevated Intraocular Pressure, Optic Nerve Atrophy, and Impaired Retinal Development in ODAG Transgenic Mice

PURPOSE. In an earlier study, a cDNA was cloned that showed abundant expression in the eye at postnatal day (P)2 but was downregulated at P10; it was named ODAG (ocular development-associated gene). Its biological function was examined by generating and analyzing transgenic mice overexpressing ODAG (ODAG Tg) in the eye and by identifying ODAG-binding proteins. METHODS. Transgenic mice were generated by using the mouse Crx promoter. EGFP was designed to be coexpressed with transgenic ODAG, to identify transgene-expressing cells. Overexpression of ODAG was confirmed by Northern and Western blot analysis. IOP was measured with a microneedle technique. The eyes were macroscopically examined and histologically analyzed. EGFP expression was detected by confocal microscope. Proteins associated with ODAG were isolated by pulldown assay in conjugation with mass spectrometry. RESULTS. Macroscopically, ODAG Tg exhibited gradual protrusion of the eyeballs. The mean IOP of ODAG Tg was significantly higher than that of wild-type (WT) littermates. Histologic analysis exhibited optic nerve atrophy and impaired retinal development in the ODAG Tg eye. EGFP was expressed highly in the presumptive outer nuclear layer and weakly in the presumptive inner nuclear layer in the ODAG Tg retina. Rab6-GTPase-activating protein (Rab6-GAP) and its substrate, Rab6, were identified as ODAG-binding proteins. CONCLUSIONS. Deregulated expression of ODAG in the eye induces elevated intraocular pressure and optic nerve atrophy and impairs retinal development, possibly by interfering with the Rab6/Rab6-GAP-mediated signaling pathway. These results provide new insights into the mechanisms regulating ocular development, and ODAG Tg would be a novel animal model for human diseases caused by ocular hypertension. (Invest Ophthalmol Vis Sci. 2009;50:242-248) DOI:10.1167/iovs.08-2206 O cular development is a complex process, involving several genes with expression that is strictly controlled in a spatial and temporal manner. Although several genes, including Pax6, Rx, and Crx, are essential for normal ocular formation, 1-3 the molecular mechanism(s) governing eye development has not been fully elucidated. To identify genes that are preferentially expressed in the developing eye, we performed a differential display using mRNAs extracted from postnatal day (P)2 and P10 mouse eyes. 4 At P2, ODAG was highly expressed in all the retinal layers (presumptive outer nuclear layer [ONL], presumptive inner nuclear layer [INL], and ganglion cell layer [GCL]), but at P7, its expression decreases, especially in the GCL, and at P14, no apparent expression is detected. To investigate, we generated transgenic mice overexpressing ODAG (ODAG Tg). The mouse Crx promoter, which directs transgene expression in photoreceptors, From th

Human CD72 splicing isoform responsible for resistance to systemic lupus erythematosus regulates serum immunoglobulin level and is localized in endoplasmic reticulum

<p>Abstract</p> <p>Background</p> <p>CD72 is an inhibitory co-receptor expressed on B cells. We previously demonstrated significant association of the polymorphism of the <it>CD72</it> gene with susceptibility to human systemic lupus erythematosus (SLE) in individuals carrying a SLE-susceptible <it>FCGR2B</it> genotype (<it>FCGR2B-232Thr/Thr</it>). The human <it>CD72</it> locus generates a splicing isoform that lacks exon 8 (CD72Δex8) as well as full-length CD72 (CD72fl), and the <it>CD72</it> polymorphism regulates exon 8 skipping.</p> <p>Results</p> <p>Here we demonstrated that individuals carrying the disease-protective <it>CD72</it> genotype exhibit significantly lower serum immunoglobulin levels than do individuals carrying other <it>CD72</it> genotypes (<it>P</it> < 0.05). Although expression level of CD72fl in the peripheral blood B cells was similar regardless of <it>CD72</it> genotype, the protein level of CD72Δex8 was increased in individuals carrying the disease-protective <it>CD72</it> genotype, suggesting a crucial role of CD72Δex8 in regulation of antibody production. By expressing these human CD72 isoforms in mouse cell lines, we further demonstrated that CD72Δex8 is accumulated in endoplasmic reticulum (ER) and fails to regulate BCR signaling whereas human CD72fl is efficiently transported to the cell surface and inhibits signaling through the B cell antigen receptor (BCR), as is the case for mouse CD72.</p> <p>Conclusion</p> <p>Human <it>CD72</it> polymorphism appears to regulate antibody production as well as susceptibility to SLE by regulating expression of ER-localizing CD72Δex8.</p

Overexpression/enhanced kinase activity of BCR/ABL and altered expression of Notch1 induced acute leukemia in p210BCR/ABL transgenic mice

Chronic myelogenous leukemia (CML) is a hematopoietic disorder, which begins as indolent chronic phase but inevitably progresses to fatal blast crisis. p210BCR/ABL, a constitutively active tyrosine kinase, is responsible for disease initiation but molecular mechanism(s) underlying disease evolution remains largely unknown. To explore this process, we employed retroviral insertional mutagenesis to CML-exhibiting p210BCR/ABL transgenic mice (Tg). Virus infection induced acute lymphoblastic leukemia (ALL) in p210BCR/ABL Tg with a higher frequency and in a shorter latency than wild-type littermates, and inverse PCR detected two retrovirus common integration sites (CISs) in p210BCR/ABL Tg tumors. Interestingly, one CIS was the transgene itself, where retrovirus integrations induced upregulation of p210BCR/ABL and production of truncated BCR/ABL with an enhanced kinase activity. Another CIS was Notch1 gene, where retrovirus integrations resulted in overexpression of Notch1 and generation of Notch1 lacking the C-terminal region (Notch1C) associated with stable expression of its activated product, C-terminus-truncated Notch intracellular domain (NICDC). In addition, generation of Tg for both p210BCR/ABL and Notch1C developed ALL in a shortened period with Stat5 activation, demonstrating the cooperative oncogenicity of Notch1C/NICDC with p210BCR/ABL involving Stat5-mediated pathway. These results demonstrated that overexpression/enhanced kinase activity of BCR/ABL and altered expression of Notch1 induce acute leukemia in a transgenic model for CML