STAT1, similar to Sp1, is a latent ubiquitous transcription factor that regulates expression of a wide range of downstream genes in response to cytokines and growth factors. STAT1 translocate to the nucleus and bind to conserved enhancer elements that lead to transcriptional activation of immediate early response genes. Although Sp1 and STAT1 are expressed ubiquitously, the expression of those genes changes according to developmental stages or cell type implying specific roles in developmental processes. The important phenotypic changes during oviductal regression and recrudescence would appear to result from a finely balanced transcriptional response by several transcription factors including Sp1 and STAT1. The third gene of interest, TF, encodes for an iron-binding protein that absorbs dietary iron from the gut and transports it throughout the body. In chickens, this gene is synthesized by both liver cells and oviduct cells, and stimulated by ARRY-142886 estrogen or dietary iron deficiency. The expression of this gene increased during oviduct regeneration indicating that it might be affect changes in gross metabolic rates. It is well known that iron is essential for various metabolic processes including DNA synthesis, oxygen transport and the electron transport system in a wide range of tissues. Dramatic tissue remodeling involving degeneration and regeneration of female reproductive organs is necessarily coupled with angiogenic processes. ANGPTL3 has features common to angiopoietins that play important roles during angiogenesis as vascular endothelial cell-specific growth factors. In the present study, there was a remarkable increase of ANGPTL3 mRNA during oviductal recrudescence which implies a requirement for re-growth of the vascular network in developing tissue. The fifth gene of interest, p20K, encodes for a small protein cloned from chicken embryo fibroblasts, and its transcription is induced in the growth arrested phase of the cell cycle such as serumdeprivation and contact-inhibition. RGS6, a member of regulator of G protein signaling proteins, negatively regulates G protein signaling by 
activating the GTPase activity. Although the precise physiological roles of p20K and RGS6 are unknown, they are linked to cellular stress responses and possess abilities to induce cell cycle arrest and apoptosis. Results from our previous studies indicate that PTN, AvBD11 and SERPINB3 are estrogen-stimulated genes during development of the chicken oviduct. PTN, also known as heparin binding growth factor 8, is a developmentally regulated growth factor which is widely distributed in various tissues. In chickens, it especially plays important roles in differentiation and morphogenesis of the embryo by promoting cell growth and migration. AvBD11, a component of egg-white proteins, is an antimicrobial peptide that plays a role in innate immunity. We reported that AvBD11 may influence oviduct development and protect the chicken embryo from pathogenic microorganisms. SERPINB3 was first identified in squamous cell carcinoma of the human uterus and, in chickens, it plays a crucial role in formation of egg yolk and egg white. Complicated actions of estrogen in various biological processes affect physiological changes XAV939 through diverse regulatory cascades by trans-activating transcription factors and inducing expression of various target genes. Because estrogen produced by the ovary may orchestrate the expression of PTN, AvBD11 and SERPINB3, temporal patterns of expression of these genes during molting and oviduct recrudescence may be closely related to changes in estrogen levels following withdrawal and restart of ovarian steroidogenesis. Taken together, tissue-specific and developmentally regulated expression of these nine genes indicates that they have regulatory functions during reproductive tissue remodeling and development of the oviduct in chickens.