Epidermal growth factor regulation of equine glycoprotein hormone alpha subunit expression in trophoblast cells.

The research article examines how Epidermal Growth Factor (EGF) controls the expression of the equine glycoprotein hormone alpha subunit gene in trophoblast cells, which are crucial components of placental structure in animals.

Article Explanation

• The study is based on the fact that primates and equids (a group that includes horses) are the only species known to express the placental glycoprotein hormone, chorionic gonadotropin (CG). This is a compound protein made of an alpha subunit tied to a hormone-specific beta subunit.
• The mechanisms behind the regulation of the equine glycoprotein alpha subunit gene expression have not been previously identified, and this research aims at filling this knowledge gap.
• The Epidermal Growth Factor (EGF) receptor is known to transmit signals that modify various cell functions, including cell proliferation, differentiation, hormone secretion, and gene regulation. Note that EGF is a protein that stimulates cell growth.
• The investigation in this research revolves around how EGF regulates the equine alpha subunit gene in trophoblasts. Trophoblasts are cells providing nutrients to the embryo and developing into a large part of the placenta.
• The findings show that the equine alpha subunit gene could be activated by EGF and phorbol 12-myristate 13-acetate (PMA), a protein kinase C (PKC) activator. PKC is an enzyme associated with several signal transduction processes.
• When the EGF receptor blocks the inhibitor of PKC, called bisindolylmaleimide-I, it was suggested that PKC is involved in the pathway downstream of EGF.
• Moreover, when PD98059, an inhibitor of the extracellular signal-regulated kinase (ERK) pathway, completely blocked the equine alpha promoter’s activation by PMA, it suggested that the mitogen-activated protein kinase (MAPK) cascade is involved downstream of the PKC pathway.
• Therefore, it’s concluded that the EGF/PKC/MAPK pathway regulates equine glycoprotein alpha subunit gene expression through a distinctive regulatory region in trophoblasts, and essential elements for the baseline expression exist within a specific region of the promoter.