Project description:As a member of the flrt gene family, Fibronectin Leucine-Rich Transmembrane 2 (flrt2) is strongly expressed in a subset of sclerotome cells, and the resultant protein interacts with FGFR1 in the FGF signaling pathway during development. Studies on flrt2 have focused mainly on its roles in the brain, heart and chondrogenesis. However, reports on its expression and function in the zebrafish retina are lacking. Here, we detected the high expression of flrt2 in zebrafish retina using in situ hybridization technique and developed an flrt2-knockout (KO) zebrafish line using CRISPR/Cas9 genome editing. Quantitative real-time PCR was used to measure the expression levels of flrt2, which results in an approximately 60% mRNA reduction. The flrt2-KO zebrafish eyes' altered morphological, cellular, and molecular events were identified using BrdU labeling, TUNEL assay, immunofluorescent staining, fluorescent dye injection and RNA sequencing. Abnormal eye development, known as microphthalmia, was found in flrt2-KO larvae, and the retinal progenitor cells exhibited increased apoptosis, perhaps owing to the combined effects of crx, neurod4, atoh7, and pcdh8 downregulation and Casp3a and Caspbl upregulation. In contrast, the retinal neural development, as well as retinal progenitor cell differentiation and proliferation, were not affected by the flrt2 deletion. Thus, flrt2 appears to play important roles in retinal development and function, which may provide the basis for further investigations into the molecular mechanisms of retinal development and evolution.
Project description:Development and function of tissues and organs are powered by the activity of mitochondria. In humans, inherited genetic mutations that lead to progressive mitochondrial pathology often manifest during infancy and can lead to death, reflecting the indispensable nature of mitochondrial function and biogenesis. Here, we describe a zebrafish mutant for the gene mia40a, the life-essential homologue of the evolutionarily conserved Mia40 oxidoreductase which drives the biogenesis of cysteine-rich mitochondrial proteins. We report that mia40a mutant animals undergo progressive cellular respiration defects and develop enlarged mitochondria in skeletal muscles before their ultimate at the larval stage. We generated a rich transcriptomic and proteomic resource that allowed us to identify abnormalities in the development of endodermal organs, in particular the liver and pancreas. We identify the acinar cells of the exocrine pancreas to be severely affected by mutations in the MIA pathway. Our data contribute to a better understanding of the molecular, cellular and organismal effects of mitochondrial deficiency, important for the accurate diagnosis and future treatment strategies of these diseases.
Project description:The RNA-binding protein FUS is implicated in transcription, alternative splicing of neuronal genes and DNA repair. Mutations in FUS have been linked to human neurodegenerative diseases such as ALS (amyotrophic lateral sclerosis). We genetically disrupted fus in zebrafish (Danio rerio) using the CRISPR-Cas9 system. The fus knockout animals are fertile and did not show any distinctive phenotype. Mutation of fus induces mild changes in gene expression on the transcriptome and proteome level in the adult brain. We observed a significant influence of genetic background on gene expression and 3’UTR usage, which could mask the effects of loss of Fus. Unlike published fus morphants, maternal zygotic fus mutants do not show motoneuronal degeneration and exhibit normal locomotor activity.