Genes involved in coenzyme Q (Q) biosynthesis, such as
coq-7/clk-1, have regulatory functions in Caenorhabditis elegans aging and development. Silencing of C. elegans coq genes lead to life span extension (Asencio et al. 2003). Mutants of coq genes have been reported for
coq-7/clk-1 and
coq-3. Only
coq-7/clk-1 mutant strains have been established, whereas
coq-3 knockouts are lethal (Hihi et al. 2002). We show that
coq-8 knock-out animals developed until L3 larval stage and then arrested. Mutants did not develop mature gonads, and showed shortened life span under dietary Q-free conditions. We also constructed a COQ-8::GFP reporter under control of
coq-8 promoter. An age-dependent pattern of
coq-8 gene expression from the embryo to senescence is reported, providing genetic evidence for Q biosynthesis regulation during development and aging. COQ-8 expression started in a few blastomeres as early as of 8th embryo mitosis and increased during larval stages in several tissues, particularly in those with active bioenergetics such as muscle, nervous system and hypodermis throughout moulting period. Maximal COQ-8 expression was detected in L3 stage, matching with the maximal Q content (Jonassen et al. 2002), and the arresting stage in
coq-8 knockouts. Non-moulting young adults did not show hypodermis COQ-8 expression and in elderly individuals expression was detected only observed in nervous system. We propose a role for
coq-8 gene supporting the regulated Q biosynthesis that fulfils ubiquinone requirements in different tissues during life cycle in C. elegans. References: Asencio, C.; Rodriguez-Aguilera, J. C.; Ruiz-Ferrer, M.; Vela, J., and Navas, P. Silencing of ubiquinone biosynthesis genes extends life span in Caenorhabditis elegans. FASEB J. 2003 Jun; 17(9):1135-7. Hihi, A. K.; Gao, Y., and Hekimi, S. Ubiquinone is necessary for Caenorhabditis elegans development at mitochondrial and non-mitochondrial sites. J Biol Chem. 2002 Jan 18; 277(3):2202-6. Jonassen, T.; Marbois, B. N.; Faull, K. F.; Clarke, C. F., and Larsen, P. L. Development and fertility in Caenorhabditis elegans
clk-1 mutants depend upon transport of dietary coenzyme Q8 to mitochondria. J Biol Chem. 2002 Nov 22; 277(47):45020-7.