Post-splenectomy spur cell hemolytic anemia

Poly(riboadenylate)-containing messenger ribonucleoprotein particles of chick embryonic muscles

“…Finally, prior to the oligo(dT)-cellulose chromatography step, the subcellular fractions, used as the sources of the two types of mRNP particles, were equilibrated against the same high ionic strength buffer. In many earlier reports dealing with the nature of the protein moieties of eukaryotic mRNP particles these conditions were not strictly followed (for a review see Greenberg, 1975; Van der Marel et al, 1975), and in several instances the mRNP particles were isolated following limited RNase treatment of subcellular fractions, e.g., polysomes and postpolysomal particles (Auerbach & Pederson, 1975;Liautard et al, 1976)-a procedure which does not leave the mRNP particles fully intact.…”

“…polypeptides ranging usually from two to thirteen in the 16000-150000-dalton range (Lebleu et al, 1971;Blobel, 1973; Bryan & Hayashi, 1973; Barrieux et al, 1975;Burns & Williamson, 1975;Chen et al, 1976;Gander et al, 1973;Gedamu et al, 1977;Irwin et al, 1975; Lindberg & Sundquist, 1974; Kumar & Pederson, 1975;Morel et al, 1973; for a review see Greenberg, 1975). Although the reported variations in the size and number of the protein components of eukaryotic polysomal mRNP particles remain a matter of considerable dispute (Williamson, 1973;Greenberg, 1975), the widespread occurrence of the two major proteins of molecular weights 52 000 and 78 000 strongly suggests that they may be specifically associated with nucleotide sequences which are common to most mRNA molecules. With regard to the interrelationship of the protein moieties of free and polysomal mRNP particles, the few published reports in the literature have led to highly conflicting conclusions.…”

“…Furthermore, low molecular weight proteins in the 15 000-30 000-dalton range, which resemble the typical ribosomal and/or cellular proteins in size, have been found in variable amounts and numbers in mRNP particles in many of these reports (Gander et al, 1973;Liautard et al, 1976; for a review see Williamson, 1973; Greenberg, 1975). Among the mRNA-associated proteins found in eukaryotic systems, the 78 000-dalton protein is currently believed to be bound specifically to the 3'-poly(A) segment of mRNA moieties of both intact polysomes and polysomal mRNP particles (Blobel, 1973; Kumar & Pederson, 1975; Kish & Pederson, 1976; Barrieux et al, 1975;Schwartz & Darnell, 1976;Janssen et al, 1976; for a review see Greenberg, 1975).…”

The poly(adenylic acid).cntdot.protein complex is restricted to the nonpolysomal messenger ribonucleoprotein of Physarum polycephalum

“…These are characteristics of the poly (A)-protein complex. In contrast, poly (A)-containing molecules released from the polysomes by RNase were re-IIlRNA1 is associated with proteins in the cytoplasm of eucaryotic cells forming mRNP particles (Greenberg, 1975; Preobrazhensky & Spirin, 1978). A significant protein binding site in mRNP is the 3'-poly(A) sequence of its mRNA moiety (Blobel, 1973).…”

Polypeptides of nonpolyribosomal messenger ribonucleoprotein complexes of sea urchin eggs

“…A 52 000-dalton protein, common to mRNPs from different sources [reviewed by Greenberg (1975)], was present in both L. pictus and S. purpuratus poly(A)-containing egg mRNPs. However, a 78 000-dalton protein, bound specifically to the 3'-poly(A) region of mRNAs in many other species [reviewed by ], was only observed in gels of S. purpuratus material.…”