Implication of mitochondria in the replication of Nodamura virus in larvae of the Lepidoptera, Galleria mellonella (L.) and in suckling mice.

The replication of Nodamura virus, type species of the family Nodaviridae, takes place principally into the interfibrillar spaces of the sarcoplasm in close association with mitochondria in the infected muscles of both G. mellonella and suckling mice. The most striking event in infection of G. mellonella muscle cells was the aggregation and shape modification of numerous mitochondria (elongation, interdigitation, and vesiculation) at an early stage of infection. These clusters of mitochondria were cemented by a thick electron-dense material at the periphery of which viral particles undergo maturation process. In a later stage, degenerated and dilated mitochondria showed a clear assembling of virus particles on their outer membrane and occasionally on some inner membranes. These facts and the localization of RNA by RNase-gold technique in the assembling sites of viruses around and inside the mitochondria allowed us to postulate a role for the mitochondria as supports and/or energy suppliers for viral RNA synthesis and translation.