Semaphorin 4F (SEMA4F)

The semaphorins comprise a large family of membrane-bound and secreted proteins, some of which have been shown to function in axon guidance. Encinas et al. (1999) cloned a novel semaphorin, which they referred to as semaphorin W (SEMAW). Sequence analysis of the SEMAW gene indicated that SEMAW is a member of the class IV subgroup of transmembrane semaphorins. The mouse and rat forms of semaphorin W share 97% amino acid sequence identity, and each shows approximately 91% identity with the human form. Expression studies showed that SEMAW mRNA is expressed at high levels in postnatal brain and lung and, unlike many other semaphorins, at low levels in the developing embryo. Functional studies showed that semaphorin W can collapse retinal ganglion cell axons.