Information génétique portée par une fraction soluble de réticulocytes et traduite en protéine spécifique sur les ribosomes d'une autre espèce

Abstract

Reticulocyte ribosomes from one species when incubated with a soluble reticulocyte fraction from another species have been shown to synthesize the haemoglobin of both species. This result supplies evidence for the presence of a messenger in the non-particulate fraction and the possible fixation of this messenger on the ribosomes of the first species. The incubation system is made of cell-free fractions from rabbit and guinea pig reticulocytes. The synthesized haemoglobins are located by double intermolecular labelling. Carrier haemoglobin, labelled with a tracer different from that used during the incubation, is added before separation of the haemoglobins. The haemoglobins are identified by isolating species-characteristic tryptic peptides containing tyrosine. The absence of any ribosomal contamination in the soluble fraction is proved. The nature and action of the active principle lead to its identification as a messenger RNA. The non-specificity of the ribosomes versus mRNA is at present accepted as a result of work with synthetic polynucleotides. The attempts to demonstrate a specific action of natural messenger on ribosomes from other species have often led to equivocal results. Our experiments, while confirming the lack of ribosomal specificity in the case of cell-free systems from rabbit and guinea pig reticulocytes, raise questions about the limits of this non-specificity.