Doublecortin (DCX) is a microtubule-associated protein expressed by neuronal precursor cells and immature neurons in embryonic and adult cortical structures. Neuronal precursor cells begin to express DCX while actively dividing, and their neuronal daughter cells continue to express DCX for 2–3 weeks as the cells mature into neurons. Downregulation of DCX begins after 2 weeks, and occurs at the same time that these cells begin to express, NeuN, a marker for mature neurons.[3]
Due to the nearly exclusive expression of DCX in developing neurons, this protein has been used increasingly as a marker for neurogenesis. Indeed, the levels of DCX expression increase in response to exercise,[4] which occurs in parallel with increased BrdU labelling, currently a "gold standard" in measuring neurogenesis.
Doublecortin was found to bind to the microtubule cytoskeleton. In vivo and in vitro assays show that Doublecortin stabilises microtubules and causes bundling.[5] Doublecortin is a basic protein with an iso-electric point of 10, typical of microtubule-binding proteins