SANJOY K. DAS, Ph.D
associate professor,
department of pediatrics and cancer biology

Currently my research focuses on two projects: (1) The process of embryo implantation is associated with uterine stromal cell decidualization, an event that is critical to the success of pregnancy. The decidualization process is characterized by stromal cell proliferation and differentiation into specialized type of cells (decidual cells) with the acquisition of polyploidy. The onset of this cellular transformation is believed to occur in a tightly regulated manner in the cell cycle at two particular checkpoints viz., G1-S and G2-M. In this regard, we previously showed that cyclin D3 (a G1 phase cell cyclin) is associated with the onset of decidualization in the mouse uterus. The objective of these studies is to define the cycle regulatory mechanisms associated during decidualization and polyploidization in implantation in mice. (2) An "early" and a "late" phase uterine response to estrogen has been recognized for more than 60 years yet mechanisms involved remain controversial. The present concept usually makes the assumption that estrogenic responses are dependent upon interaction with one of the two receptors (ER-alpha or ER-beta). However, identification of gene expression following the injection of estrogenic ligands, in ER-alpha null mice has shown this to be an oversimplification. Recently, we identified several downstream target genes regulated early by estrogens in the uterus by an ER-independent mechanism. The primary goal of these studies is to demonstrate that while early estrogenic responses are ER-independent, the late responses are ER-dependent, and a cooperation between the two phases are necessary for a full complement of estrogenic growth response in the uterus.