The ubiquitin proteosome system (UPS) functions in the cell to mark specific proteins for degradation. E3 ubiquitin ligases act as recognition factors and increase the specificity of the UPS. MEX-3 is an RNA binding protein in Caenorhabditis elegans that inhibits the translation of PAL-1, a posterior specifying protein, and contributes to development of the anterior of the embryo. MEX-3 is present throughout the oocyte, 1-cell, and 2-cell embryo. However, MEX-3 is then depleted in the posterior after the second cell division, and PAL-1 is then expressed in the two posterior blastomeres of the 4-cell embryo. MEX-3 is rapidly depleted from the entire embryo after the 8-cell stage. This degradation is location and time specific, and thus hypothesized to be caused by the UPS. MEX-3 is hypothesized to be targeted for degradation by a specific E3 ubiquitin ligase, and knockout of this protein should result in increase in universal MEX-3 expression in the early embryo. This study sought to determine the MEX-3 specific E3 ubiquitin ligase(s). Putative E3 ubiquitin ligases expressed during early embryonic development were knocked out in C. elegans, and phenotypes were determined. Of the knocked-out ligase genes, only one, ZK858.4 caused embryonic lethality at both 15Ëš and 24Ëš C. However, fluorescence microcopy of GFP::MEX-3 demonstrated that ZK858.4 knockout did not appear to increase global MEX-3 concentrations. Determining which protein targets MEX-3 degradation will provide more insight into the molecular mechanisms of determining anterior/posterior patterning in C. elegans early embryonic development.