Maturation of postnatally generated olfactory bulb granule cells depends on functional γ-protocadherin expression

γ-protocadherins (γ-pcdhs) are transmembrane receptor proteins ubiquitously expressed in the postnatal and adult mouse brain. γ-pcdhs are required for normal neuronal development as shown for spinal cord interneurons, retinal ganglion cells and cortical neurons. To test the role of γ-pcdhs during development of subventricular zone progenitor cells and their subsequent differentiation into olfactory granule cells we generated a conditional γ-pcdh(lox/lox) allele (γ-pcdh(lox/lox)) allowing for functional γ-pcdh inactivation upon lentivirus-mediated Cre-recombinase expression selectively in subventricular zone progenitor cells. While γ-pcdh loss did not alter the proliferation of subventricular zone progenitors, γ-pcdh ko progenitors that reached the main olfactory bulb showed a significant reduction in dendritic arborization and failed to develop dendritic spines. Our results suggest that olfactory bulb granule cell maturation necessitates functional γ-pcdh expression.