Changes in protein expression associated with the developmental transition from permissive to restrictive states of spinal cord repair in embryonic chick.

In this study we examined protein changes accompanying a developmental loss of axon regeneration in the spinal cord occurring around embryonic day 13 (E13) of spinal cord development in the chick. We employed high resolution two-dimensional (2D) gel electrophoresis to identify proteins consistently altering their expression around this critical period. Spinal cord protein fractions were isolated from E8, E10, E12, E14, E16, E18 and post-hatching day 2 spinal cord and separately run on a high resolution 2D gel system. Protein spots were visualized with silver staining and subsequently analyzed. Ten proteins were identified, termed developmental spinal cord proteins (DSPs), with five increasing and five decreasing their abundance over the developmental period studied. Apparent molecular weight and isoelectric points have been calculated and are reported. Further studies, currently underway, will be required to determine if these identified proteins are involved in the developmental loss of regenerative ability.