TY - JOUR T1 - Chemoattraction and Chemorepulsion of Olfactory Bulb Axons by Different Secreted Semaphorins JF - The Journal of Neuroscience JO - J. Neurosci. SP - 4428 LP - 4436 DO - 10.1523/JNEUROSCI.19-11-04428.1999 VL - 19 IS - 11 AU - Fernando de Castro AU - Lingjia Hu AU - Harry Drabkin AU - Constantino Sotelo AU - Alain Chédotal Y1 - 1999/06/01 UR - http://www.jneurosci.org/content/19/11/4428.abstract N2 - During development, growth cones can be guided at a distance by diffusible factors, which are attractants and/or repellents. The semaphorins are the largest family of repulsive axon guidance molecules. Secreted semaphorins bind neuropilin receptors and repel sensory, sympathetic, motor, and forebrain axons. We found that in rat embryos, the olfactory epithelium releases a diffusible factor that repels olfactory bulb axons. In addition, Sema A and Sema IV, but not Sema III, Sema E, or Sema H, are able to orient in vitrothe growth of olfactory bulb axons; Sema IV has a strong repulsive action, whereas Sema A appears to attract those axons. The expression patterns of sema A and sema IV in the developing olfactory system confirm that they may play a cooperative role in the formation of the lateral olfactory tract. This also represents a further evidence for a chemoattractive function of secreted semaphorins. ER -