title: Development and fertility in Caenorhabditis elegans clk-1 mutants depend upon transport of dietary coenzyme Q8 to mitochondria.
abstract: The Caenorhabditis elegans clk-1 mutants lack coenzyme Q(9) and instead accumulate the biosynthetic intermediate demethoxy-Q(9) (DMQ(9)). clk-1 animals grow to reproductive adults, albeit slowly, if supplied with Q(8)-containing Escherichia coli. However, if Q is withdrawn from the diet, clk-1 animals either arrest development as young larvae or become sterile adults depending upon the stage at the time of the withdrawal. To understand this stage-dependent response to a Q-less diet, the quinone content was determined during development of wild-type animals. The quinone content varies in the different developmental stages in wild-type fed Q(8)-replete E. coli. The amounts peak at the second larval stage, which coincides with the stage of arrest of clk-1 larvae fed a Q-less diet from hatching. Levels of the endogenously synthesized DMQ(9) are high in the clk-1(qm30)-arrested larvae and sterile adults fed Q-less food. Comparison of quinones from animals fed a Q-replete or a Q-less diet establishes that the Q(8) present is assimilated from the E. coli. Furthermore, this E. coli-specific Q(8) is present in mitochondria isolated from fertile clk-1(qm30) adults fed a Q-replete diet. These results suggest that the uptake and transport of dietary Q(8) to mitochondria prevent the arrest and sterility phenotypes of clk-1 mutants and that DMQ is not functionally equivalent to Q.
mesh_terms: D000818:Animals; D001692:Biological Transport / Q000502:physiology*; D017173:Caenorhabditis elegans / Q000166:cytology / Q000235:genetics / Q000254:growth & development* / Q000502:physiology; D029742:Caenorhabditis elegans Proteins; D004032:Diet; D017238:Genes, Helminth; D015801:Helminth Proteins / Q000235:genetics* / Q000378:metabolism; D007814:Larva / Q000502:physiology; D008928:Mitochondria / Q000737:chemistry / Q000378:metabolism*; D009154:Mutation; D011809:Quinones / Q000378:metabolism; D013696:Temperature; D014451:Ubiquinone / Q000378:metabolism*
chemical_list: C104339:CLK-1 protein, C elegans; D029742:Caenorhabditis elegans Proteins; D015801:Helminth Proteins; D011809:Quinones; D014451:Ubiquinone; C030778:ubiquinone 8