Peripubertal requirement of Tsg101 in maintaining the integrity of membranous structures in mouse oocytes.

Objective: As a component of Endosomal Sorting Complex Required for Transport (ESCRT) complex I, the tumor susceptibility gene 101 (Tsg101) carries out multiple functions. In this work, we report that oocyte-specific deletion of tumor susceptibility gene 101 (Tsg101) leads to age-dependent oocyte demise in mice.

Materials And Method: Tsg101 floxed mice (Tsg101 ) were bred with Zp3 transgenic mice to examine oocyte-specific roles of Tsg101. Multiple cellular and molecular biological approaches were taken to examine what leads to oocyte demise in the absence of Tsg101.

Results: The death of oocytes from Zp3 /Tsg101 (Tsg101 thereafter) mice showed a strong correlation with sexual maturation, as gonadotropin-releasing hormone antagonist injections improved the survival rate of oocytes from 5-week-old Tsg101 mice. Maturation of oocytes from prepubertal Tsg101 mice proceeded normally, but was largely abnormal in oocytes from peripubertal Tsg101 mice, showing shrinkage or rupture. Endolysosomal structures in oocytes from peripubertal Tsg101 mice showed abnormalities, with aberrant patterns of early and late endosomal markers and a high accumulation of lysosomes. Dying oocytes showed plasma membrane blebs and leakage. Blockage of endocytosis in oocytes at 4°C prevented cytoplasmic shrinkage of oocytes from Tsg101 mice until 9 h. The depletion of tsg-101 in Caenorhabditis elegans increased the permeability of oocytes and embryos, suggesting a conserved role of Tsg101 in maintaining membrane integrity.

Conclusions: Collectively, Tsg101 plays a dual role in maintaining the integrity of membranous structures, which is influenced by age in mouse oocytes.