engleski

Dissecting RNA Polymerase II transcription termination complex in Saccharomyces cerevisiae using a dosage-suppressor assay as a tool

Transcription and export of competent mRNPs are coupled by the CTD (Carboxy Terminal Domain) of RNA polymerase II that serves as a platform for seyuential recruitment of different protein factors. Defective mRNPs are recognised, retainde, and degraded by nuclear quality contro. Our team have developed a system to artificially disrupt mRNP biogenesis in the cell to better understand the molecular mechanisms involved in the recognition of defective mRNPs. We have shown that one of the major components of quality control is the NRD complex whose association with the CTD allows the recognition of aberrant transcripts and their elimination by the nuclear exosome. This quality control may be destroyed if certain proteins involved in transcription termination are over-expressed, thus preventing the detection/destruction of defective mRNPs. To understand how this delicate balance between transcription termination proteins and surveillance system operates in the cell, we have over-expressed several transcription termination factors in vivo and analysed the consequences in the cells where defective mRNPs were synthesised. This research has shown that proteins involved in transcription termination have distinct roles: the over-expression of some proteins disrupts the process of recognition of defective mRNPs while the others do not show this effect.

quality control; transcription termination; aberrant transcripts; mRNP

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