Mitochondrial ATP synthase controls larval development cell nonautonomously in Caenorhabditis elegans

The mitochondrial respiratory chain is composed of five protein complexes capable of generating cellular energy in the form of ATP. Defects in mitochondrial energy production can result in a wide variety of diseases with tissue-specific effects. We previously have isolated a mutation in the atp-2 gene, which encodes the active site or beta-subunit of complex V in Caenorhabditis elegans. This atp-2(ua2) mutation is lethal, resulting in developmental arrest at the third larval stage (L3). In this report, we use mosaic analysis to identify the tissues in which atp-2 gene activity is dispensable for development past the L3 stage. The loss of atp-2 in any tissue can provoke arrest at the L3 stage. However, animals with a loss of the atp-2 gene in the ABa lineage, which gives rise to neuronal, pharyngeal, and hypodermal cells, and/or the E lineage, which gives rise to the intestinal cells, can occasionally develop past L3. Loss of atp-2 gene function in the lineages that give rise to the body muscles is invariably associated with developmental arrest. This finding suggests that the body muscles may play a key role in regulating development. We conclude that atp-2 functions cell nonautonomously in this developmental process. Our findings suggest that atp-2 is involved in the production or the regulation of a global, developmental signal required for the L3-to-L4 transition.