Previous studies have shown that NACHT, leucine rich repeat and PYD domain containing 5 (Nlrp5) deficient embryos fail to develop beyond the two-cell stage. Despite this strong phenotype, little is known of the function of NALP5 and the pathways affected by its deficiency. We showed that Nlrp5 deficient oocytes and embryos exhibit a decrease in caspase activity. In addition, the kinetics of NF-κB-p65 nuclear translocation is altered, which leads to negative downstream effects. Autophagy is known to be regulated downstream of NF-κB and is a key event during the oocyte-to-embryo transition. We observed defective execution of autophagy in Nlrp5 deficient two-cells evidenced by absence of autophagosome formation and abnormal lysosomal maturation. We found that inactivating autophagy leads to an accumulation of lipid droplets and embryos lacking Nlrp5 exhibit this accumulation. Thus, NALP5 may be an integral component responsible for autophagy mediated lipid metabolism, which when compromised causes developmental arrest.

Previous studies have shown that NACHT, leucine rich repeat and PYD domain containing 5 (Nlrp5) deficient embryos fail to develop beyond the two-cell stage. Despite this strong phenotype, little is known of the function of NALP5 and the pathways affected by its deficiency. We showed that Nlrp5 deficient oocytes and embryos exhibit a decrease in caspase activity. In addition, the kinetics of NF-κB-p65 nuclear translocation is altered, which leads to negative downstream effects. Autophagy is known to be regulated downstream of NF-κB and is a key event during the oocyte-to-embryo transition. We observed defective execution of autophagy in Nlrp5 deficient two-cells evidenced by absence of autophagosome formation and abnormal lysosomal maturation. We found that inactivating autophagy leads to an accumulation of lipid droplets and embryos lacking Nlrp5 exhibit this accumulation. Thus, NALP5 may be an integral component responsible for autophagy mediated lipid metabolism, which when compromised causes developmental arrest.

Nlrp5, a maternal-effect gene, is required for embryonic progression and female fertility in mice. Previous work indicated an age-related decline in Nlrp5 transcripts in murine oocytes. As maternal age is associated with increased spindle organization defects, studies in this thesis focused on the analysis of meiotic spindle defects in oocytes of Nlrp5-deficient mice. NALP5 protein showed a novel kinetochore-localization pattern, which was disturbed by spindle poisons. Nlrp5-deficient oocytes displayed a higher frequency of spindle abnormalities and chromosomal misalignment. Upon fertilization, these defects translated into increased incidences of multinucleation. As these phenotypes are associated with deficiencies in genome stability, we examined spindle assembly checkpoint (SAC) components. We found that numerous SAC proteins were dysregulated, implying that NALP5 may be critical in sensing oocyte-related SAC defects. We found that Nlrp5-deficient oocytes may have increased DNA damage. Thus, Nlrp5 may be an integral component responsible for preservation of genome integrity in female gametes.

Nlrp5, a maternal-effect gene, is required for embryonic progression and female fertility in mice. Previous work indicated an age-related decline in Nlrp5 transcripts in murine oocytes. As maternal age is associated with increased spindle organization defects, studies in this thesis focused on the analysis of meiotic spindle defects in oocytes of Nlrp5-deficient mice. NALP5 protein showed a novel kinetochore-localization pattern, which was disturbed by spindle poisons. Nlrp5-deficient oocytes displayed a higher frequency of spindle abnormalities and chromosomal misalignment. Upon fertilization, these defects translated into increased incidences of multinucleation. As these phenotypes are associated with deficiencies in genome stability, we examined spindle assembly checkpoint (SAC) components. We found that numerous SAC proteins were dysregulated, implying that NALP5 may be critical in sensing oocyte-related SAC defects. We found that Nlrp5-deficient oocytes may have increased DNA damage. Thus, Nlrp5 may be an integral component responsible for preservation of genome integrity in female gametes.