{"type":"root","children":[{"type":"paragraph","children":[{"type":"text","value":"The progesterone receptor (PR) also known as nuclear receptor subfamily 3, group C, member 3 (NR3C3), is an intracellular steroid receptor that specifically binds progesterone. PR is encoded by a single gene PGR residing on chromosome 11q22; it has two main forms, A and B, which differ in their molecular weight and N-terminal regions. Like all steroid receptors, the progesterone receptor has an amino and a carboxyl terminal, and between them the regulatory domain, a DNA binding domain, the hinge section, and the hormone binding domain. The binding of progesterone to the receptor triggers a cascade of events that influence cell growth, differentiation, and other functions. PRs are highly expressed in the mammary gland, uterus, and other reproductive tissues, where they mediate the effects of progesterone on development, menstruation, and pregnancy."}]}]}