Loss of the Mia40a oxidoreductase leads to hepato-pancreatic insufficiency in the zebrafish

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. Overall design: Embryos obtained from an in-cross of heterozygous mia40awaw1/+ siblings were genotyped at 3 dpf. Pools of five mia40+/+ or mia40waw1/waw1 larvae, derived from the same clutch, were collected at indicated time-points for RNA extraction and transcriptomic profiling. Larvae used in 8 dpf experiments were subjected to external feeding from 5dpf before being collected for the analysis at 8dpf.

12

Sokol AM, Uszczynska-Ratajczak B, Collins MM, Bazala M, Topf U, Lundegaard PR, Sugunan S, Guenther S, Kuenne C, Graumann J, Chan SSL, Stainier DYR, Chacinska A