Glucose 6-phosphate dehydrogenase deficiency enhances germ cell apoptosis and causes defective embryogenesis in Caenorhabditis elegans

Yang, H-C; Chen, T-L; Wu, Y-H; Cheng, K-P; Lin, Y-H; Cheng, M-L; Ho, H-Y; Lo, S J; Chiu, D T-Y

High degree of conservation in G6PD gene from nematode to human. G6PD is ubiquitously present in living organisms from bacteria to mammals. Based on the aminoacid sequence alignment (Figure 1a) , mouse (Mus musculus) G6PD shows the highest homology (93%) compared with human (Homo sapiens) G6PD, followed by zebrafish (Danio rerio, 74%), fruit fly (Drosophila melanogaster, 61%), nematode (C. elegans, 56%), yeast (Saccharomyces cerevisiae, 45%), and bacteria (Escherichia coli, 34%). Similar to eukaryotic G6PD homologues, including fruit fly, zebrafish, and mouse, C. elegans G6PD contains a shorter amino terminus compared with human counterpart (Figure 1a ). In addition, C. elegans G6PD is separated from multicellular eukaryotic and microbial G6PD homologues in the phylogenetic tree (Figure 1b) . Although microbial G6PD homologues display lower degree of conservation compared with human counterpart, it has been shown that the bacterial form of G6PD exerts antioxidant activity in G6PD-nullizygous mouse embryonic stem cells. 23 Based on the high degree of conservation between C. elegans and human, it is speculated that C. elegans G6PD is a functional homologue of human G6PD.