Effect of a dipeptide inhibiting ubiquitin-mediated protein degradation nerve-dependent limb regeneration in the newt.
The dipeptide Leu-Ala, which inhibits ubiquitin-mediated protein degradation, has been shown to act in vitro as an inhibitor of neurite outgrowth of PC12 cells (Hondermarck et al. [1992] Biochem. Biophys. Res. Commun. 189:280). Using agarose beads as vehicles, we tested, in vivo, the effect of this dipeptide (and the inactive inverse, Ala-Leu, as a control) on limb regeneration in the newt (Triturus cristatus), a nerve-dependent developmental process. Leu-Ala inhibited the growth of mid-bud blastemas without altering blastema differentiation, while Ala-Leu had no effect. Cytological observations of dipeptide-treated blastemas using Bodian staining or neurofilament antibodies showed that all the blastema tissues were unmodified except with regard to innervation. Leu-Ala-treated blastemas were devoid of nerve fibers in the epidermal cap, while the mesenchyme distal to the dipeptide impregnated bead exhibited fewer nerve fibers than did Ala-Leu-treated blastemas, which were similar to the control nontreated blastemas. Thus, Leu-Ala, in reducing blastema innervation, inhibits its growth in the same manner as surgical denervation.
Taban
C H
CH
Centre de Biologie Cellulaire, Université de Lille, F-59655 Villeneuved'Ascq Cedex, France.
Hondermarck
H
H
Bradshaw
R A
RA
Biolly
B
B
D000818:Animals; D004151:Dipeptides / Q000494:pharmacology; D005121:Extremities / Q000033:anatomy & histology / Q000294:innervation / Q000502:physiology; D011506:Proteins / Q000378:metabolism; D012038:Regeneration / Q000187:drug effects / Q000502:physiology*; D014319:Triturus; D014452:Ubiquitins / Q000502:physiology*
D004151:Dipeptides; D011506:Proteins; D014452:Ubiquitins