| Description |
ATP-binding cassette (ABC) subfamily B member 10 (Abcb10) is a mitochondrial ABC protein that is important in red cell hemoglobinization. Abcb10 is located on the mitochondrial inner membrane and is suggested to export an unknown substrate out of the mitochondria. Loss of Abcb10 is embryonic lethal, and reduced expression using shRNA in MEL cells results in decreased hemoglobin synthesis with a reduction in the expression of heme synthesis genes expression. The central hypothesis of this thesis is that the substrate exported by Abcb10 is necessary for signaling to induce transcription of heme synthesis genes transcription. This study utilized metabolomic and transcriptomic approaches to identify the effects of the loss of Abcb10 in undifferentiated and differentiated MEL cells. This study has determined that the reduction or loss of Abcb10 affects arginine metabolism. Loss of Abcb10 caused an intracellular accumulation of citrulline and ornithine and a depletion of arginine. RNA sequencing revealed that the loss of Abcb10 caused broad transcriptional changes with over 3000 genes differentially expressed (p 0.05) in the absence of Abcb10. Transcripts for arginine uptake (CAT1) were elevated, but transcripts for intracellular arginine synthesis (Ass1 and Asl) were decreased. Decreased expression of genes involved in oxidative phosphorylation and increased transcripts for genes involved in glucose metabolism were also observed. This study's findings suggest that in the absence of Abcb10 MEL cells were unable to shift from glycolysis to oxidative phosphorylation, which is necessary for hemoglobinization. |
