The Role of BLM Helicase in Mammalian Microhomology-Mediated End Joining

Abstract

DNA repair pathways are important for the maintenance of genomic integrity and critical to the survival and health of an organism. In order to effectively eliminate damaged segments of DNA, DNA repair mechanisms require the separation of the two complementary strands?or a helicase. While the enzyme BLM helicase is implicated in several DNA damage repair mechanisms, its role in non-homologous repair of DNA double strand breaks through microhomology-mediated end joining (MMEJ) is of concern in this study as previous studies have suggested that BLM helicase is necessary for MMEJ. Under this, it was hypothesized that cells lacking BLM helicase would not undergo MMEJ as readily as those with the protein, thereby containing less DNA degradation fragments. This was to be determined by performing DNA degradation assays on cell lysates lacking and not lacking the BLM helicase protein and comparing results from the two sample pools, noting up regulation or down regulation of MMEJ in BLM knockdown samples. Thus far, optimization of the BLM helicase RNAi transfection process was accomplished to successfully produce knockdown of BLM helicase expression in the two experimental cell lines. Future studies regarding this experiment involve performing the degradation assays to test the aforementioned hypothesis.