Analysis of a zebrafish semaphorin reveals potential functions in vivo

The semaphorin/collapsin gene family is a large and diverse family encoding both secreted and transmembrane proteins, some of which are thought to act as repulsive axon guidance molecules. However, the function of most semaph orins is still unknown. We have cloned and characterized several semaphorin s in the zebrafish in order to assess their in vivo function. Zebrafish sem aZ2 is expressed in a dynamic and restricted pattern during the period of a xon outgrowth that indicates potential roles in the guidance of-several axo n pathways. Analysis of mutant zebrafish with reduced semaZ2 expression rev eals axon pathfinding errors that implicate SemaZ2 in normal guidance. Dev Dyn 1999;214: 13-25. (C) 1999 Wiley-Liss, Inc.