X-linked Huwe1 is essential for oocyte maturation and preimplantation embryo development

Summary HUWE1 is a HECT-domain ubiquitin E3 ligase expressed in various tissues. Although HUWE1 is known to promote degradation of the tumor suppressor p53, given a growing list of its substrates, in vivo functions of HUWE1 remain elusive. Here, we investigated the role of HUWE1 in the female reproductive system. Homozygous deletion of Huwe1 in mouse oocytes of primary follicles caused oocyte death and female infertility, whereas acute depletion of HUWE1 protein by Trim-Away technology did not impact oocytes from antral follicles. Interestingly, oocytes from Huwe1 heterozygous females matured and fertilized normally, but the majority of embryos that lacked maternal Huwe1 were arrested at the morula stage after fertilization. Consequently, Huwe1 heterozygous females only produced wild-type pups. Concomitant knockout of p53 did not recover fertility of the Huwe1 knockout females. These findings place HUWE1 as a unique and critical maternal factor indispensable for maintaining the quality of oocytes and embryos.