RNA polymerase II (pol II) synthesised RNAs encode for proteins (mRNA), aid in splicing and telomere maintenance (snRNPs), and down-regulate gene expression (microRNAs). Therefore, pol II can be a critical target for modulating differential gene expression. Understanding mechanisms that underlie the various stages of transcription will elucidate origins of gene misexpression, which can give rise to a host of human diseases. Eleven-nineteen lysine-rich in leukaemia, (ELL), affects pol II transcription. The ELL gene was initially identified as a gene translocation fusion partner of the mixed lineage leukaemia (MLL) gene in patients with acute myeloid leukaemia (I). ELL interacts with pol II in vitro, increasing the rate at which it elongates nascent transcripts (2). Two ELL-associated factors, EAFI and EAF2, bind ELL family members and act as strong positive regulators of their transcription activities (3).
Although ELL and EAF orthologs have been identified in metazoan organisms, previous attempts to identify similar elongation factors in lower eukaryotes had been unsuccessful. This thesis describes the identification of two genes in the yeast Schizosaccharomyces pombe, ell I and eafl, that share some sequence similarity to highly conserved regions in ELL and EAEI/EAF2 (4). Biochemical characterisation of these gene products, SpELL and SpEAF, shows that they have similar activities to their metazoan counterparts in vitro. Using a whole genome approach, I identified genes that are likely direct targets for regulation by SpELL/SpEAF in cells. Notably, ELL and EAF functions have not been studied previously at a genomic level. One SpELL/SpEAF target, sme2, was used as a model gene to investigate how the SpELL/SpEAF complex is recruited to chromatin. Together with results of in vitro binding assays, these results suggest the SpELL/SpEAF complex is recruited to pol II via the SpELL subunit
