Characterization of protein components of poly(A)-containing messenger ribonucleoproteins from cryptobiotic gastrulae of Artemia salina.

Conditions for the isolation of intact poly(A)+mRNP from cryptobiotic gastruale of A. salina are described. In the presence of Mg2+ ions nucleolytic cleavage occurs in vitro in the vicinity of the 3'-poly(A) segment of mRNP during the isolation procedure. The resulting two parts of poly(A)+mRNP complex are separated by thermal elution from oligo(dT)-cellulsoe affinity column. Analysis by SDS-gel electrophoresis of protein components associated with intact poly(A)+mRNP has revealed the existence of 20--30 S RNP complex containing five major proteins with Mr 68,000, 53,000, 50,000, 45,000 and 38,000, respectively, but completely lacking the poly(A)-specific Mr 76,000 protein.