[Effect of low-molecular nuclear RNA on RNA synthesis in isolated nuclei].

An attempt was made to elucidate possible participation of low molecular weight nuclear RNA's (LMWN RNA's) in the transcription process. For this purpose, we studied the effect of individual fractions of LMWN RNA's, isolated by polyacrylamide gel electrophoresis, on the endogenous RNA synthesis in isolated nuclei. We have found no influence of LMWN RNA's on the incorporation of labeled precursors in the acid-insoluble material under the conditions when RNA polymerase I is predominantly active. The results obtained thus indicate that LMWN RNA's do not participate in the regulation of 45S pre-rRNA synthesis and they do not belong to limiting factors in pre-rRNA synthesis.