TY - THES ID - 134949609 TI - LEDGF/p75 and HRP2, cellular cofactors involved in disease AU - De Coster, Michiel AU - Debyser, Zeger AU - Hendrix, Jelle AU - KU Leuven. Faculteit Wetenschappen. Opleiding Master in de biochemie en de biotechnologie (Leuven) PY - 2020 PB - Leuven KU Leuven. Faculteit Wetenschappen DB - UniCat UR - https://www.unicat.be/uniCat?func=search&query=sysid:134949609 AB - Translocations of the KMT2A gene are frequently observed in acute leukemias with particularly poor prognoses. Fusion of KMT2A with one of over 90 different partner genes establishes an oncogenic gene expression program via the expression of a chimeric protein. Despite the diversity of fusion partners, all retain the N-terminal region of KMT2A. Consequently, a common feature of all known KMT2A oncoproteins is the formation of a ternary complex, comprising MENIN and lens epithelium-derived growth factor p75 (LEDGF/p75), on the N-terminus. Various studies have demonstrated the importance of the KMT2A-MENIN-LEDGF/p75 ternary complex in KMT2A-r leukemogenesis. Herein, LEDGF/p75 serves as a molecular tether targeting the oncogenic fusion protein to the chromatin in a manner reminiscent to its role as a cellular cofactor in Human Immunodeficiency Virus type-1 (HIV-1) infection. Functionally, the N-terminal integrase binding domain (IBD) and C-terminal Pro-Trp-Trp-Pro (PWWP) domain of LEDGF/p75 are essential to facilitate these pathogenic processes. Aside from LEDGF/p75, hepatoma derived growth factor (HDGF)-related protein 2 (HRP2) is the only other protein to contain both an IBD and a PWWP domain. Unpublished results from our group have demonstrated the binding of HRP2 to the N-terminal fragment of KMT2A, suggesting a potential role in KMT2A-r leukemia. In line with a prior study showing impaired proliferation of KMT2A-transformed cells upon depletion of LEDGF/p75, a knockdown of HRP2 was examined. This revealed an impaired growth of cells upon depletion of HRP2. Interestingly, the role of HRP2 in cellular growth was seemingly independent of KMT2A-fusions, suggesting a more general pro-survival role. In this thesis, the effect of HRP2 knockdown on growth was evaluated in various leukemic and non-leukemic cell lines. The results confirmed a KMT2A-fusion independent effect on growth upon depletion of HRP2. Furthermore, in light of the COVID-19 pandemic, a role of LEDGF/p75 in facilitating nucleosome accessibility was examined using previously acquired AFM images. Whilst the analysis did not demonstrate an obvious role of LEDGF/p75, more data would have to be acquired to draw solid conclusion. ER -