Osmoregulation of ribosomal function in mouse liver

Initiation factors in protein synthesis by free and membrane-bound polyribosomes of liver and hepatoma

“…Labelled rat hepatic phenylalanyl-tRNA was prepared by the method of Moldave (1963) with some modifications described by Pilkis & Korner (1971 Poly(U)-directed polyphenylalanine synthesis with I M-KCl-washed ribosomes at low Mg2+ concentrations (3-5mM) has been shown to require several protein factors which are recovered from the 0.5-1.OM-KCI washings (Grummt & Bielka, 1971;Murty et al, 1971Murty et al, , 1974bLynn et al, 1973;Picciano et al, 1973;Schreir & Staehelin, 1973). In the present study, ribosomal wash fraction and salt-washed riboVol.…”

“…Initiation factors were prepared from total, free and membrane-bound polyribosomes as described previously (Lynn et al, 1973;Murty et al, 1974b). After preparation ofthe ribosomal pellets as described above, they were rinsed and resuspended in 2.5 ml of buffer A (containing 20mrnm-Tris-HCl (pH7.6), 5mM-MgCl2, 100mM-KCI, 1 mM-dithiothreitol, 0.25mM-EDTA and 10% (v/v) glycerol].…”

“…Subsequently, a number of investigators have reported that the active components of the ribosomal wash in liver are protein factors that are required for the initiation of mRNA translation in eukaryotes (Grummt & Bielka, 1971;Murty et al, 1971;Lynn etal., 1973;Picciano etal., 1973;Schreier & Staehelin, 1973). In a number of reports (Lynn et al, 1973;Lanclos & Bresnick, 1972;Murty et al, 1974a), alterations in the hepatic activity of initiation factors have been observed under certain experimental conditions. Also, the activity of initiation factors of transplantable hepatoma H5123 appeared to be different from that of host liver (Murty et al, 1974b).…”

Initiation Factors in Protein Synthesis of Liver and Skeletal Muscle of Rats Force-Fed a Threonine-Devoid Diet

“…The assay for poly-(U) -directed polyphenylalanine synthesis was carried out as described earlier (19). The assays for the binding of 14C-phe-tRNA and 14C-met-tRNA to salt-washed ribosomes in the presence of inittiation factors were carried out by the methods of Shafritz and Anderson (12) and (20) Nirenberg and Leder (22).…”

“…Initiation factors and salt-washed ribosomes were prepared from hepatic and skeletal muscle ribosomes as described earlier (19). Ribosomal pellets prepared as described above were rinsed and resuspended in 2.5 ml Buffer A (containing 20 mM Tris-HC1 (pH 7.4), 5 mM Mg2+, 100 mM KCI, 1 mM dithiothreitol, 0.25 mM EDTA and 10% glycerol) and the ribosomal suspension was treated with a high-salt buffer (20 mM Tris-HC1 (pH 7.4), 15 mM Mg2+, 2 M KCI, 1 mM dithiothreitol, 0.25 mM EDTA and 10% glycerol) to a final concentration of 1 M KCl.…”