Identification of nonhistone protein LMG160 as a ribonucleoprotein of the nuclear matrix with a role in transcription in vitro

In this study a fraction of low mobility group nuclear proteins, designated LMG160 has been identified as a ribonucleoprotein (RNP) which is detectable in the RNP-containing nuclear matrix of hepatocyte cells through western blot analysis. Using different in vitro transcription systems in the absence and presence of LMG160, it is shown that the intact form of the protein causes a strong inhibition of DNA-templated RNA synthesis in a dose dependent manner. Removal of the RNA moiety with RNase decreased its inhibitory effect. These results indicate, for the first time, the nuclear position of the LMG160 protein, with a regulatory role on transcription, which might be a quite important finding to better understanding of the biological function of this protein in rat liver nuclei.