DNA-dependent RNA polymerases from Artemia salina: Characterization of a protein factor from developing embryos that stimulates Artemia RNA polymerase II

Dormant encysted embryos of the brine shrimp, Artemia salina, contain a protein factor (S protein) that stimulates transcription of both native and denatured DNA by Artemia RNA polymerase II. Stimulatory activity is associated with a 15 S complex containing several polypeptides. Two polypeptides, comprising 65% of the total mass, have molecular weights of 183,000 and 67,000 and are present in a molar ratio of 1:2. The 15 S complex can not be dissociated under nondenaturing conditions. S protein has no stimulatory effect on RNA polymerases from Escherichia coli, Drosophila, or mammals. The presence of S protein increases the number of RNA chains synthesized by Artemia RNA polymerase II. During preemergence development of encysted embryos and early development of hatched larvae, stimulatory activity and the polypeptides characteristic of the 15 S complex disappear.