The RNA binding protein La influences both the accuracy and the efficiency of RNA polymerase III transcription in vitro.

摘要: The autoantigen La binds the U-rich 3' ends of all nascent RNA polymerase III transcripts. Here, we demonstrate that this abundant nuclear phosphoprotein not only these RNAs but appears to be required for their synthesis. HeLa cell extracts immunochemically depleted by either patient or mouse monoclonal antibodies lose greater than 99% transcription activity on class genes. few transcripts synthesized in absence have fewer uridylate residues at those made its presence. Reconstitution La-depleted with biochemically purified protein stimulates levels and completely restores transcript length. A model coupling action termination signal is presented.