Identification and characterization of splice variants of ephrin-A3 and ephrin-A5

Ephrins and Eph receptors have been implicated to play important roles in a xon guidance, A variable spacer region exists that differs significantly am ong distinct ephrins, An ephrin-A5 isoform has previously been isolated whi ch lacks 27 amino acids within the spacer region, The expression and biolog ical activities of this isoform, as well as the existence of isoforms for o ther ephrins that show variation within the spacer region, remain unknown, We report here a novel alternatively spliced isoform of ephrin-A3 which lac ks the corresponding variable region. When compared to the longer isoforms, the shorter isoforms of both ephrin-A3 and ephrin-A5 remained less promine nt in the brain during development, though their expression increased at po stnatal stages. In addition, they could inhibit neurite outgrowth of dorsal root ganglia (DRG) neurons, suggesting that the corresponding variable reg ions mere not essential for their axon guidance activities. (C) 1999 Federa tion of European Biochemical Societies.