J. Neurochem.(2010)115, 910–920.AbstractSuccessful axonal regeneration is a complex process determined by both axonal environment and endogenous neural capability of the regenerating axons in the central and the peripheral nervous systems. Numerous external inhibitory factors inhibit axonal regeneration after injury. In response, neurons express various regeneration‐associated genes to overcome this inhibition and increase the intrinsic growth capacity. In the present study, we show that the brain‐expressed X‐linked (Bex1) protein was over‐expressed as a result of peripheral axonal damage. Bex1 antagonized the axon outgrowth inhibitory effect of myelin‐associated glycoprotein. The involvement of Bex1 in axon regeneration was further confirmedin vivo. We have demonstrated that Bex1 knock‐out mice showed lower capability for regeneration after peripheral nerve injury than wild‐type animals. Wild‐type mice could recover from sciatic nerve injury much faster than Bex1 knock‐out mice. Our findings suggest that Bex1 could be considered as regeneration‐associated gene.