Expression of SUMO associated proteins in the mouse endometrium is regulated by ovarian hormones throughout the estrous cycle.

The modification of proteins by small ubiquitin-like modifier (SUMO), known as SUMOylation, regulates biological function by changing protein transcription and translation. During the estrous cycle the endometrium undergoes continual change to processes including cell proliferation, secretion and exfoliation and these changes are regulated by the levels of ovarian hormones. Increasing the expression of SUMO family members has previously been shown to promote proliferation and invasion of endometrial cancer cells. However, limited research has been carried out into the expression and function of SUMO in the mammalian endometrium. In the present study, the level and localization of SUMO-associated proteins throughout the natural estrous cycle in the mouse uterus was determined using immunohistochemical staining and western blot analysis. The association between the spatiotemporal expression of these SUMO modified proteins and SENPs in endometrium and the concentration of ovarian hormones during estrous cycle was revealed. The present study clarified the role of SUMOylation in maintenance of normal estrous cycling and may have important significance in the study of hormone-dependent endometrial diseases.