簡要描述：Semaphorin 7a is required for central and peripheral axon growth and is required for proper axon tract formation during embryonic development. Semaphorin 7a is also involved in modulating immune function. Semaphorin 7a expression is highest in the brain and increases in late embryonic and postnatal stages. The Semaphorins constitute a large family of secreted and membrane-tethered cell signaling molecules. They have functions in neural development, immunology, cardiac growth, vascular deve