The ER stress and cytopathologies seen in the hi559 liver resemble those seen in human NAFLD. Furthermore, Gene Set Enrichment Analysis (GSEA) of microarray data identified selective enrichment of genes involved in ERSR pathway in hi559 larvae; several of these genes are selectively overexpressed in the mutant liver. Together, these data support a model in which disrupted PtdIns synthesis leads to ER stress–mediated intracellular damage resulting in hepatic pathology

similar to that seen in NAFLD. CDIPT, CDP-diacylglycerol-inositol 3-phosphatidyltransferase; dpf, days postfertilization; ER, endoplasmic reticulum; ERSR, endoplasmic reticulum stress response; GI, gastrointestinal; GSEA, Gene Set Enrichment Analysis; ISH, in situ hybridization; mRNA, messenger RNA; NAFLD, nonalcoholic Selleck SCH727965 fatty liver disease; ORO, Oil Red O; PCR, polymerase chain reaction; PI, phosphoinositides; PIS, phosphatidylinositol synthase; RAD001 ic50 PtdIns, phosphatidylinositol; RT-PCR, reverse-transcription PCR;

UPR, unfolded protein response. The zebrafish line hi559 was obtained from a large-scale insertional mutagenesis screen.8 All fish husbandry was performed in accordance with local institutional animal care and use committee protocols. Heterozygous and homozygous fish were confirmed by way of genotyping using multiplex polymerase chain reaction (PCR). CY3-streptavadin (CY3-SA) labeling was performed as illustrated previously.7 For whole-mount in situ hybridization (ISH), embryos were processed as described.5 Probes and their corresponding accession numbers are provided in the Supporting Information. Alkaline phosphatase staining for vasculature and whole-mount Oil Red O (ORO) staining were

performed as described.21, 22 Total RNA was extracted only from 5-dpf wild-type and hi559 larvae using RNAeasy (Qiagen). Oligo dT–primed complementary DNA was then synthesized using SuperScript II RT (Invitrogen) and probed by way of reverse-transcription PCR (RT-PCR). cdipt mRNA was synthesized from a full-length linear DNA template using mMessage (Ambion) and purified by RNA clean (Zymo Research). cdipt and gfp mRNAs were injected into 1-cell stage embryos. For knockdown analyses of Cdipt, two zebrafish cdipt splice-blocking morpholinos were coinjected with tp53 morpholino into wild-type embryos. tp53 morpholino alone was injected as a control morpholino. See Supporting Information for primer and morpholino sequences. The PIS assay was performed essentially as described.23, 24 The assay was conducted in 100 μL total volume containing 0.2 mM CDP-DAG, 0.5 mM myo-[3H]inositol (5,000 cpm/nmol), 2 mM MnCl2, 50 mM Tris-Hcl (pH 8.0), 0.15% Triton X-100, and 50 μg of total protein isolated either from wild-type or hi559 larvae. After 1 hour of incubation at 37°C, the reaction was terminated by adding 0.35 mL chloroform and 0.5 mL 1 M MgCl2.