RT Journal Article
SR Electronic
T1 Dual Action of a Ligand for Eph Receptor Tyrosine Kinases on Specific Populations of Axons during the Development of Cortical Circuits
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 4663
OP 4672
DO 10.1523/JNEUROSCI.18-12-04663.1998
VO 18
IS 12
A1 Valérie Castellani
A1 Yong Yue
A1 Pan-Pan Gao
A1 Renping Zhou
A1 Jürgen Bolz
YR 1998
UL http://www.jneurosci.org/content/18/12/4663.abstract
AB The structural basis of cortical columns are radially oriented axon collaterals that form precise connections between distinct cortical layers. During development, these connections are highly specified from the initial outgrowth of collateral branches. Our previous work provided evidence for positional cues confined to individual layers that induce and/or prevent the formation of axon collaterals in specific populations of cortical neurons. Here we demonstrated within situ hybridization techniques that mRNA of the Eph receptor tyrosine kinase EphA5 and one of its ligands, ephrin-A5, are present in distinct cortical layers, at a time when intrinsic connections are being formed in the cortex. Axonal guidance assays indicate that ephrin-A5 is a repellent signal for a populations of axons that in vivo avoid the cortical layer expressing ephrin-A5. In contrast to its established role as a repulsive axonal guidance signal, ephrin-A5 specifically mediates sprouting of those cortical axons that target the ephrin-A5-expressing layer in vivo. These results identify a novel function of ephrin-A5 on axonal arbor formation. The laminar distribution and the dual action on specific populations of axons suggest that ephrin-A5 plays a role in the assembly of local cortical circuits.