Study of the role of the A12.2 subunit from RNA polymerase I in Saccharomyces cerevisiae

The S. cerevisiae RNA polymerase I is a multisubunit enzyme composed of 14 subunits involved in the 35S pre-ribosomal RNA (pre-rRNA 35S) transcription. In order to understand the biological function of the non-essential subunits of this complex, especially the conserved subunit Rpa12, we follow two approaches involving a genetic screen (research of second site mutation suppressors) and a two-hybrid screen. The yeast two-hybrid screen allowed the cloning of a fragment of the Rrp5 protein involved in the 35S pre-rRNA maturation revealing a new interaction between PolI and the pre-rRNA 35S maturation machinery. We have also isolated a fragment containing the conserved domain A and B of Rpa135, the second Pol I largest subunit, wich could be the anchorage region of Rpa12 in PolI. Further studies have investigated the interactions between Rpa12 and Rpa135 subunits and was included in a large investigation of the Pol I subunits interactions.