Differential expression of a gene highly homologous to c-ras during the development of the brine shrimp Artemia

Abstract

We report the identification of p21 ras and a cDNA coding for it in the crustacean Artemia. The monoclonal antibody Y13-259 immunoprecipitates a polypeptide of 21.5 kDa in 24 hr-old larvae. The homology of p21 ras with the Drosophila melanogaster and the mammalian p21s is in the order of 75-80%. mRNA (of 1.2 kb in length) is already present in encysted gastrulae, and the levels increase, reaching a maximum before emergence. On the contrary, both the amount of p21 ras and its GTP-binding activity are low prior to emergence and rises afterwards. These results suggest that p21 ras expression is regulated post-transcriptionally, and that its function(s) is needed for post-hatching events, the more likely being the resumption of cell proliferation.