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Characterizing The Heavy Metal Chelator, Tpen, As A Ca2+ Tool In The Mammalian Oocyte, Robert A. Agreda Mccaughin

Masters Theses 1911 - February 2014

N,N,N’,N’-tetrakis-(2-Pyridylmethyl) ethylenediamine (TPEN) is a heavy metal chelator with high affinity for zinc. TPEN causes important responses in mammalian eggs. For example, these eggs are arrested at the MII stage by the Endogenous Mitotic Inhibitor 2 (Emi2), which prevents activation of the Anaphase Promoting Complex (APC) and degradation of Cyclin B. By chelating zinc, TPEN inactivates Emi2 and eggs undergo spontaneous exit of meiosis and egg activation. TPEN chelates Ca²⁺ with lower affinity, although in the Endoplasmic Reticulum (ER), where Ca²⁺ concentrations are high, TPEN may sequester Ca²⁺ preventing release into the cytoplasm. Initial exposure of TPEN …