HEREDITARY ABNORMAL ACTIVATION IN PLEURODELES WALTL OOCYTES

A mutation which affects the eggs was detected in a Pleurodeles waltl laboratory strain. About 4 to 5 hours after fertilization, i.e. before the first cleavage, mutant eggs exhibited one or more depigmented pat ches (DR) on the animal hemisphere. Later on, some eggs failed to clea ve, or cleaved abnormally. However, if gastrulation was successful, fu rther development occurred normally. Abnormal eggs showed a disorganiz ation of the vitelline gradient as well as a large lens-like zone of h yaline cytoplasm lying under the DP and a heterogeneous distribution o f actin and tubulin in the inner cytoplasm. This mutation was named tu rbulent egg cytoplasm (tec). The alterations described above seem to b e related to modifications of the cytoskeleton. Since artificially act ivated tee ova also exhibited the mutant pattern, we may conclude that the tee phenotype is expressed as a maternal effect syndrome.