Deficiency in Bbc3 increases neuron number in the adult retina. (A) Histological analysis of the retinas of Bbc3-/- and Bbc3+/- mice (aged 6 weeks or more) reveal an increase in thickness of inner nuclear layer (INL), suggesting an increase in INL neurons. Similarly, there appears to be an increase in ganglion cell layer (GCL) neurons. The retinas of Bax-/- mice also appeared to have an increase in INL and GCL cells. However, no obvious increase in cell number was preset in Bax heterozygous mice. No increase in the number of photoreceptors, which make up the outer nuclear layer (ONL) was observed in either Bbc3 or Bax deficient retinas. (B) To confirm the observation of an increase in GCL neurons in Bbc3 and Bax deficient retinas, GCL neurons were stained in flat mount using a modified Nissl stain. (C) Cell counts confirmed an increase in GCL neurons in Bbc3-/-, Bbc3+/-, and Bax-/- neurons. At least 5 retinas were counted per genotype. Note, for cell counts, endothelial cells were excluded based on their elongated morphology. *, P < 0.05; scale bar, 100 μm in A, 50 μm in C.