Diversity and Specificity of Actions of Slit2 Proteolytic Fragments in Axon Guidance

• Published in: The Journal of neuroscience 2001-06, Vol.21 (12), p.4281-4289
• Main Authors: Ba-Charvet, Kim T. Nguyen, Brose, Katja, Ma, Le, Wang, Kuan H, Marillat, Valerie, Sotelo, Constantino, Tessier-Lavigne, Marc, Chedotal, Alain
• Format: Article
• Language: English
• Subjects: Alkaline Phosphatase - genetics; Animals; Axons - drug effects; Axons - metabolism; Cells, Cultured; Chemotaxis - drug effects; COS Cells; Ganglia, Spinal - cytology; Ganglia, Spinal - metabolism; Growth Cones - drug effects; Humans; Intercellular Signaling Peptides and Proteins; Mutagenesis, Site-Directed; Nerve Tissue Proteins - chemistry; Nerve Tissue Proteins - genetics; Nerve Tissue Proteins - metabolism; Neurons, Afferent - cytology; Neurons, Afferent - drug effects; Olfactory Bulb - cytology; Olfactory Bulb - metabolism; Peptide Fragments - chemistry; Peptide Fragments - genetics; Peptide Fragments - pharmacology; Protein Binding - genetics; Rats; Rats, Sprague-Dawley; Receptors, Immunologic - metabolism; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism; Roundabout Proteins; Slit2 protein
• ISSN: 0270-6474; 1529-2401
• DOI: 10.1523/jneurosci.21-12-04281.2001

The Slits are secreted proteins that bind to Robo receptors and play a role in axon guidance and neuronal migration. In vertebrates, Slit2 is a major chemorepellent for developing axons and is involved in the control of midline crossing. In vivo, Slit2 is cleaved into 140 kDa N-terminal (Slit2-N) and 55-60 kDa C-terminal (Slit2-C) fragments, although the uncleaved/full-length form can also be isolated from brain extract. We explored the functional activities of Slit2 fragments by engineering mutant and truncated versions of Slit2 representing the N-, C-, and full/uncleavable (Slit2-U) fragments. Only Slit2-N and Slit2-U bind the Robo proteins. We found that in collagen gel, olfactory bulb (OB) but not dorsal root ganglia (DRG) axons are repelled by Slit2-N and Slit2-U. Moreover, only Slit2-N membranes or purified protein-induced OB growth cones collapse. Finally, we found that only recombinant Slit2-N could induce branching of DRG axons and that this effect was antagonized by Slit2-U. Therefore, different axons have distinct responses to Slit2 fragments, and these proteins have different growth-promoting capacities.