[Study of the function of low molecular weight nuclear RNA in the cell-free system of isolated nuclei]

Possible involvement of small nuclear RNAs in transcription was explored. The fraction of small (4-8S) nuclear or cytoplasmic RNAs was isolated by Sepharose 4B gel chromatography and its influence on the RNA synthesis in isolated nuclei was studied. Small nuclear or cytoplasmic RNAs stimulated RNA synthesis in isolated nuclei both in the presence and in the absence of cytosol. On the contrary, the influence of E. coli tRNA or high molecular weight cytoplasmic RNA varied depending on the presence of cytosol. The data indicate that small nuclear RNAs may participate in transcription although the mechanisms of their involvement demand further investigation.