Prokineticin receptor 2 expression identifies migrating neuroblasts and their subventricular zone transient-amplifying progenitors in adult mice.

The adult subventricular zone (SVZ) contains progenitors cells, which continually give rise to new neurons that migrate along the rostral migratory stream (RMS) to the olfactory bulbs (OB). Prokineticin receptor 2 (ProKR2) is a G-protein-coupled receptor that plays an essential role in this migration process. However, the identity of the prokr2-expressing cells has not yet been clearly established. Here, we have characterized in detail the identity of the prokr2-expressing cells in the SVZ/RMS/OB pathway in adult mice. In the SVZ, accumulation of prokr2 transcripts was detected in almost all migrating neuroblasts or type A cells as well as in a large population of their precursors, the rapidly dividing type C cells. Moreover, we observed that, in dissociated SVZ cells from Mash1::GFP postnatal mice, ProKR2 protein is also present in type C and type A cells. We found that, along the RMS and in the OB, prokr2 expression was restricted to migrating type A cells and was absent in astrocytes. Finally, we observed a highly marked decrease of prokr2 expression in Mash1-/- mutant mice, suggesting that this transcription factor directly or indirectly regulates prokr2 expression. Although the expression of ProKR2 in migrating type A cells is in good agreement with the essential role played by this receptor during this migration process, its expression in a large population of their progenitors suggests an additional function for ProKR2, providing novel insights into the role of ProKR2/ProK2 signalling in adult neurogenesis.