Effects of in vitro Incubation and X-irradiation on the Ribonucleic Acid fractions of Rabbit Lymphatic Cells

The yield of metabolically distinct fractions of RNA separated from rabbit lymphatic cells by phenol treatment changed during the in vitro incubation. The amount of the major component of the phenol-released fraction, pRNA-B, was kept rather constant, while the yield of the residual fraction with a very high turnover rate (rRNA) decreased during the course of the incubation. The in vitro incorporation of 32P-orthophosphate into pRNA-B was not affected by a 800 r X-irradiation in vitro of lymphatic cells but that into rRNA was depressed to the same extent as that into DNA.