Master thesis - University of Veterinary Medicine Vienna - 2022

mRNAs interact with RNA-binding proteins (RBPs) as well as with other coding and non-coding RNAs in the context of ribonucleoprotein complexes (RNPs). RBPs are important in nearly all post-transcriptional processes of RNA metabolism, including splicing, alternative polyadenylation, localization, surveillance, decay and translation. RNA-binding proteins are aberrantly expressed in various cancer types, including acute myeloid leukemia (AML), which is a neoplasm of the myeloid blood lineage, causing aberrant expansion of immature cells at the expense of mature cell production. Processing bodies (P-Bodies) are membraneless cytoplasmic foci containing mRNPs associated with translational repression and mRNA decay machineries. DDX6 is a member of the DEAD-box RNA helicase family which is essential for the assembly and maintenance of P-bodies in eukaryotic cells. Furthermore, it has been shown that DDX6 is able to control cell fate in a context-dependent manner. This work aims to elucidate the role of DDX6 in malignant hematopoiesis, since its role in controlling differentiation vs. self-renewal has not been studied in AML. Analysis of publicly available gene expression databases revealed that DDX6 levels are higher in cancer cells than in healthy cells. Western blot and RT-qPCR analysis confirmed that DDX6 protein and mRNA levels are elevated in mouse and human AML cell lines and patient samples compared to untransformed hematopoietic progenitor cells. CRISPR/Cas9-mediated gene knockout and doxycycline-inducible shRNA-mediated knockdown showed that DDX6 is essential for AML cell proliferation. Furthermore, DDX6 loss caused the dissolution of P-bodies in AML cells, confirming its requirement for their assembly and maintenance. Together, this work contributes to a deeper understanding of the function of DDX6 during malignant hematopoiesis.

Masterarbeit - Veterinärmedizinische Universität Wien - 2022

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V, 58 Blätter