Development of the somatosensory cortex, the cerebellum, and the main olfactory system in Semaphorin 3F knockout mice.

Semaphorin 3F (Sema3F) is a secreted type of the semaphorin family of axon guidance molecules. Sema3F and its receptor Neuropilin-2 (Npn-2) mRNAs were distributed in a mutually exclusive manner throughout mouse brain development. In order to examine physiological roles of Sema3F, we generated Sema3F knockout mice (KO) by gene targeting in embryonic stem (ES) cells. We found that the loss of Sema3F expression did not significantly affect the mRNA expression of Npn-2 or the other putative Npn-2 ligands, namely, Sema3B, Sema3C, or Sema3G. The barrel structure of the somatosensory cortex and the cerebellar neuroanatomy were not significantly altered in Sema3F KO. Finally, optical imaging of intrinsic signals of the dorsal olfactory bulb showed no significant differences in odor map between wild-type mice and Sema3F KO. These data suggest that Sema3F plays a relatively restricted, if any, role in its receptor expression and postnatal development of these brain structures.