Characterization of two temperature-sensitive mutants of Sigma virus (authors transl)

Summary Temperature-sensitive mutants have been isolated from Drosophila Sigma virus, a Rhabdovirus inducing CO₂ sensitivity in Drosophila melanogaster. We have studied the decay of infectious centers at non permissive temperature. The proportion of destroyed infectious centers is the same for the wild type, ts⁺, and for ts9. On the opposite, it is more important for ts 4. Temperature-sensitive function of ts 4 appears necessary to the viral genome replication. With the three clones, ts⁺, ts 4 and ts 9, we have obtained stabilized Drosophila females able to transmit Sigma virus to their whole progeny. We have tried to see in each case, if stabilized flies could transmit the virus to their progeny at non permissive temperature. Flies stabilized with ts⁺ and ts 9 can, flies stabilized with ts 4 cannot. Therefore two categories of mutants are defined: those that are transmitted hereditarily. at non permissive temperature, and not blocked in genome replication. Those that are blocked in genome replication and not transmitted. When the virus cannot replicate, the divisions in the germ line cells dilute the viral genomes. The consequence will be a real healing of germ line cells, and then a break in hereditary transmission by stabilized flies. All the results with temperature-sensitive mutants are coherent with this hypothesis.

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Étude de mutants thermosensibles du virus Sigma

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Mémoire présenté par F. Gros