Human Rnase P And Transcription

Human nuclear RNase P has been initially characterized by virtue of its ability to process the 5′ leader sequence of precursor tRNA. This ribonucleoprotein complex consists of H1 RNA subunit and at least ten distinct protein components. However, recent findings reveal that RNase P has a role in transcription by RNA polymerase I (Pol I) and Pol III. RNase P associates with these two polymerases, binds to chromatin of rDNA, 5S rRNA and tRNA genes, and determines the transcriptional output of these polymerases in the nucleus. The molecular mechanism(s) by which RNase P acts on transcription are being investigated. This essay summarizes some aspects of old and new functions of this remarkable ribonucleoprotein.