RNA polymerase III (pol III) is responsible for transcribing a set of genes that are involved in protein synthesis, including transfer (tRNA) and 5S ribosomal RNA (5S rRNA). Pol III transcription levels are increased in many cancers, as increased protein synthesis is required for tumour growth. Furthermore, it has been shown that a number of oncoproteins and tumour suppressor proteins interact directly with the pol III machinery. The work presented in this thesis aimed to investigate whether the inhibitor of differentiation (ID) and E47 proteins regulate pol III transcription, as well as the mechanisms behind these processes.