Olfactory marker protein （OMP） which is expressed in the cytoplasm of olfactory chemosensory neurons in the nasal neuroepithelium， is associated in a unique way with the mature olfactory receptor neurons in numerous vertebrate species. OMP have a modulatory part in the odor detection/signal transduction cascade ant its expression is a sign of mature vertebrate olfactory receptor neurons （ORNs）. OMP is also a potent enhancer of mitosis in fetal olfactory epithelial cells and it promotes an increase in uptake of tritiated thymidine in liver.
