Has a role in germline cell development and proliferation which affects the frequency of apoptosis. Required for mitochondrial DNA replication and transcription and fertility. Interacts with nmad-1. Expressed in eggs. Expressed at low levels in L1 larvae and increases at the L3 stage to the adult stage. Reduced mitochondrial replication, transcriptional hypoxia response, sterility, arrest of germline cell proliferation, reduced frequency of apoptosis in the germline. Severe mitochondrial DNA depletion in somatic cells but does not result in major anomalies in worms development. Hypersensitive to ethidium bromide.