Expression pattern of Calbindin-D28k, NeuN proteins, ATOH1 and EN2 genes in the human fetal cerebellum

Certain molecules are expressed specific to cerebellar neurons and certain genes play specific role in the development of cerebellum. This is a descriptive observational study carried out in human fetal cerebellum, fluorescent immunohistochemistry was used to study the expression of Calbindin-D28k and neuronal nuclease (NeuN), and while the expression of ATOH1 (Atonal homolog 1) and EN2 (Engrailed -2) genes were quantified with the help of qPCR. Calbindin-D28k was highly immunoreactive in the Purkinje cells and located in their cytoplasm, nucleus and dendrites whereas absent in their axons. NeuN was expressed weakly in the perinuclear cytoplasm and nucleus of granule cells whereas absent in their dendrites and axons. ATOH1 gene was upregulated during third trimester whereas EN2 gene was upregulated during second as well as third trimesters. Distribution and intensity of Calbindin-D28k and NeuN proteins in the human fetal cerebellum increased with the increase of fetal age. Expression of ATOH1 and EN2 genes indicated that second and third trimesters are the crucial periods for the proliferation, migration and maturation of granule cells and essential for the establishment of normal morphology of human fetal cerebellum and its development. • Calbindin-D28k expresses in Purkinje cells, except their axons, during development. • NeuN shows weak expression in granule cells and absent in their axons and dendrites. • ATOH1 gene upregulates in third trimester, crucial for granule cell maturation. • EN2 gene upregulates in second and third trimesters for the cerebellar development.