Semaphorins are secreted or membrane-bound proteins that are essential for the development, as well as the maintenance of many organs and tissues. In the development of the spinal cord, semaphorin signaling pathways play a major role in the regulation of neuronal morphology and migration, as well as function in axon guidance, and are responsible for the organisation of ascending and descending tracts formed by crossing axons within the white matter. Semaphorins are known axon guidance molecules in the differentiation of spinal cord neurons, but how these signaling pathways are important for neuroprogenitor cell differentiation is not well known. Based on the fact that both neuropilins and plexin A2 well-known receptors for Sema 3 mediated signaling pathways were expressed by the spinal progenitor cells, we aimed to analyse the possible functional consequences of inhibition of these signalling pathways in spinal neuroprogenitor cells using chicken embryo model. We used plasmid-based dominant- negative (DN) technology to inhibit the signaling pathway transmitted by neuropilin 1 and 2 receptors. We microinjected the DN-neuropilin 1, 2, or control GFP plasmids into the 4.5-day old chicken embryos’ central canal and transfected them by in Ovo electroporation. After 24h and 72h survival time, those cells expressing either the DN-neuropilin 1 or 2 were stuck in the ventricular zone compared to the control GFP expressing spinal cords. The growth of the neuroprogenitor cells’ basal processes and leading processes of the postmitotic neurons were impaired in those cells expressing DN-neuropilin 2 as opposed to cells’ processes expressing DN-neuropilin 1 which were defasciculated. After treatment and incorporation of BrdU into the transfected cells, results revealed that DN-neuropilin 2 cells are postmitotic while DN- neuropilin 1 cells do not leave the cell cycle. Our study indicated that the Sema 3 signalling pathway through neuropilin receptors has differential roles in development and progression in the cell cycle of neuroprogenitor cells in the spinal dorsal horn just as during interkinetic and radial migration.