PNAS 2014-10-07

Beclin-1 deficiency in the murine ovary results in the reduction of progesterone production to promote preterm labor.

Thomas R Gawriluk, CheMyong Ko, Xiaoman Hong, Lane K Christenson, Edmund B Rucker

Index: Proc. Natl. Acad. Sci. U. S. A. 111(40) , E4194-203, (2014)

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Abstract

Autophagy is an important cellular process that serves as a companion pathway to the ubiquitin-proteasome system to degrade long-lived proteins and organelles to maintain cell homeostasis. Although initially characterized in yeast, autophagy is being realized as an important regulator of development and disease in mammals. Beclin1 (Becn1) is a putative tumor suppressor gene that has been shown to undergo a loss of heterozygosity in 40-75% of human breast, ovarian, and prostate cancers. Because Becn1 is a key regulator of autophagy, we sought to investigate its role in female reproduction by using a conditional knockout approach in mice. We find that pregnant females lacking Becn1 in the ovarian granulosa cell population have a defect in progesterone production and a subsequent preterm labor phenotype. Luteal cells in this model exhibit defective autophagy and a failure to accumulate lipid droplets needed for steroidogenesis. Collectively, we show that Becn1 provides essential functions in the ovary that are essential for mammalian reproduction.