BBB seminar: Torben Heick Jensen

Connections between transcription, mRNP assembly and quality control in S. cerevisiae

Torben Heick Jensen
Department of Molecular Biology, Århus University, Denmark

Over the past few years, we have studied the connections between transcription, mRNP assembly and quality control in the yeast Saccharomyces cerevisiae. Processing of mRNA and proper formation of messenger ribonucleoprotein particles (mRNPs) require co-transcriptional loading of proteins onto nascent transcripts. Mutations in several genes involved in mRNA processing, nuclear export and in mRNP assembly lead to production of aberrant mRNPs that are retained in transcription site-foci and partially degraded by the nuclear exosome of 3'-5' exonucleases. Such detection and removal of erroneous messages presumably constitutes a quality control serving to protect the cell from contamination of otherwise unwanted molecules.

Lately, we have also demonstrated a prominent role of the rate of transcription in the constitution of an export-competent mRNP. Our data suggest that a decreased transcription rate generally favours proper mRNP formation under challenging conditions. These results reinforce the tight coupling between transcription and various mRNA metabolic events including removal of the message.