KLF3 is a member of the Kruppel-like factor family and is a potent transcriptional repressor. KLF3 is comprised of two domains; a functional domain at the N-terminus and a DNA binding domain (DBD) at the C-terminus. We have recently demonstrated using chromatin immunoprecipitation combined with massively parallel DNA sequencing (ChIP-seq) that, surprisingly, the functional domain of KLF3 is involved in the in vivo genomic localisation of this transcription factor. Using loss-of-function experiments, we showed that KLF3 DBD alone goes to far fewer genomic locations than full-length KLF3. Gain-of-function experiments support this hypothesis – when the KLF3 functional domain is fused to an unrelated artificial DNA-binding domain the functional domain takes the artificial DNA-binding domain to new places in the genome, a significant portion of which are KLF3 target sites. We are interested in determining how the non-DNA binding functional domain contributes to genomic localisation and hypothesise that this occurs through binding to a novel KLF3 functional domain partner protein. The aim of this project is to identify this KLF3 functional domain partner protein. We have made use of HEK293 stably expressing mouse KLF3 functional domain only and an empty vector control. V5-KLF3 has been immunoprecipitated from these cells by virtue of the V5 tag using an anti-V5 antibody and partner candidates have been identified by mass spectrometry. Interestingly, WDR5 was a potential candidate which interacted with KLF3 in vivo. The importance of WDR5 in genomic localisation will be determined in mouse embryonic fibroblast stem cell (MEF) stably expressing V5-KLF3 full length by presence or absence of WDR5 using ChIP.