[Sequence of RNA and protein synthesis in wound fibroblasts]

RNA and protein synthesis was studied in the mouse granulation tissue fibroblasts on the 3d and 7th days after wound production. An electron-radioautographic modification of the double marker method, based on the supposition that the two biosynthetic processes investigated occur, mainly, in different parts of the cell, was worked out. Synthesis rates were determined in radioautographs obtained after administration of a mixture of labelled RNA and protein precursors to the animals. There was but a slight difference in density of the label over the nucleus and cytoplasm, nevertheless, in some cells either nucleus or cytoplasm were predominantly labelled and, as the investigation of serial sections demonstrated, this phenomenon was not occasional. Existence of similar fibroblasts should be explained by the suggestion that RNA and protein syntheses increase in the cell not simultaneously but successively.