Interaction between a complex of RNA polymerase III subunits and the 70-kDa component of transcription factor IIIB.

A system that detects the formation of complexes between different proteins by linking them to separate domains of the GAL4 transcription activator protein has been used to study protein-protein interactions between four essential and unique subunits of yeast RNA polymerase III (C82, C53, C34 and C31), the 70-kDa component of the initiation transcription factor IIIB (TFIIIB70) and the TATA-binding protein. We found that C82, C34, and C31 are able to combine with each other in vivo and that C34 interacts with TFIIIB70. These results suggest that C34 and TFIIIB70 are specificity determinants of the RNA polymerase III-TFIIIB interaction.