Notch signaling represses GATA4-induced expression of genes involved in steroid biosynthesis

What is it about?

In this paper we demonstrate that Notch signaling inhibits the expression of steroidogenesis genes in response to FSH in the granulosa cells of small follicles and in MA-10 Leydig cells. We further demonstrate that the downstream effector genes Hey1, Hey2, and HeyL act directly on the promoters of GATA activated genes of the steroidogenesis pathway and inhibits their transcription.

Featured Image

Why is it important?

Follicle stimulating hormone has dual effects on follicle cells based on the size of the follicle. Granulosa cells of small follicles proliferate in response to FSH, while those of larger follicles express the genes of the steroidogenesis pathway. However, how FSH produced these two different responses is largely unknown. We found that Notch signaling inhibits the expression of steroidogenesis genes in small follicles and in Leydig cells and further acts directly on their promoters. This is the first indication of another pathway that regulates the response of granulosa cells to this hormone.