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Presents a list of research papers to be published in the upcoming issues of the "European Journal of Biochemistry." "Extraction and Translation of Collagen mRNA From Fetal Calf Skin," by R. Kaufman, A. Belayew, B. Nusgens, and C. M. Lapie&rgrave;e; "Messenger RNA For Ribosomal Proteins in Xenopus laevis Oocytes," by P. Pierandrei-Amaldi and E. Beccari; "Purification and Characterization of Esterase 2B of the House Mouse, Mus musculus," by U. Lexow, A. Ronai, and O. von Deimling.

The methylation of HeLa cell ribosomal proteins has been studied by paper electrophoresis separation of the peptides produced after trypsin digestion of individual ribosomal proteins. Methylation in vivo was detected by 3H labeling of peptides from cells that had been incubated with a mixture of [methyl-3H]methionine plus [35S]methionine, the incorporation of the 3H-labeled amino acid methionine being corrected by the 35S uptake. Each methylated peptide thus represented at least one methylation site (one or more methylated amino acids and their adjacent amino acid sequence). Eleven ribosomal proteins were found to be methylated. As many as five methylation sites were present in one ribosomal protein. In several ribosomal proteins some sites were methylated when ribosome synthesis was suppressed with low levels of actinomycin D, while other sites were not. Therefore, some of the sites in a given protein were apparently methylated in mature ribosomes, while other sites were methylated during ribosome processing. The methyl-group-specific labeling of some sites, but not others, was suppressed by cycloheximide, thus suggesting that the methylation of some sites was dependent on protein synthesis. A cell-free system from cultured HeLa cells is described, which reproduces the methylation pattern of ribosomal proteins in vivo in two ways: methylation was observed both in vivo and in vitro (a) in the same ribosomal proteins; and (b) in the same methylation sites of a given ribosomal protein. In addition, our data in vitro suggest that the methylation of some human ribosomal protein sites may involve a methyl donor other than S-adenosylmethionine. [ABSTRACT FROM AUTHOR]

This paper describes three types of experiments which indicate that the binding sites for elongation factor 1 (EF-1) and elongation factor 2 (EF-2) on ascites cell ribosomes are not identical and perhaps not even overlapping. The experimental evidence presented includes direct competitive binding of labeled elongation factors to ribosomes as well as the influence of pokeweed antiviral protein and Escherichia coli anti-L7/L12 proteins on the binding and function of the two factors. It is further shown that EF-1β from Artemia salina does not function in displacing EF-1 from mouse ascites tumor cell ribosomes. These results also support our recently proposed model that EF-1 remains bound to the ribosome during the peptide chain elongation cycle. [ABSTRACT FROM AUTHOR]

Translation of cellular and early vaccinia RNA in nuclease-treated lysates, derived from uninfected and vaccinia-virus-infected cells al the early stage, has been investigated. When using limiting amounts of RNA no discrimination of translation was observed in the infected cells lysates; This conclusion was confirmed by sensitive RNA competition experiments for translation in vitro and also when using two different fractionated systems for protein synthesis in vitro. This absence of detectable discrimination in vitro was established both by comparing incorporation of [35S]methionine into proteins and by analysis of the products thus synthesized by sodium dodecylsulfate gel electrophoresis. However, a modification of the translational machinery from vaccinia-virus-infected cells did occur since only the ribosomal salt wash derived from infected cells was able to reverse the inhibition of protein synthesis in vitro resulting from excess RNA (control or early). This property of vaccinia-virus-infected cell lysates may result from the synthesis of an early protein involved in translation or from a better recovery of translational factors from the infected cells., as suggested in the accompanying paper. [ABSTRACT FROM AUTHOR]