Increased slow transport in axons of regenerating newt limbs after a nerve conditioning lesion
| Autor: | C. Eberhardt Maier, Irvine G. McQuarrie |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
Nervous system
medicine.medical_treatment Biology Lesion Calmodulin Tubulin medicine Animals Regeneration Axon Molecular Biology Regeneration (biology) Microfilament Proteins Extremities Cell Biology Anatomy Salamandridae Actins Axons medicine.anatomical_structure Amputation Axoplasmic transport Electrophoresis Polyacrylamide Gel Axotomy medicine.symptom Carrier Proteins Microtubule-Associated Proteins Blastema Developmental Biology |
| Zdroj: | Developmental Biology. 140:172-181 |
| ISSN: | 0012-1606 |
| DOI: | 10.1016/0012-1606(90)90064-p |
| Popis: | We have previously shown that a nerve conditioning lesion (CL) made 2 weeks prior to amputation results in an earlier onset of limb regeneration in newts. Studies in fish and mammals demonstrate that when a CL precedes a nerve testing lesion, slow component b (SCb) of axonal transport is increased compared to axons that had not received a CL. We wanted to know whether the earlier initiation of limb regeneration after a CL was associated with an increase in SCb transport. The transport of [35S]methionine labeled SCb proteins was measured by using SDS-PAGE, fluorography, and scintillation counting. The rate of transport and quantity of SCb proteins was determined at 7, 14, 21, and 28 days after injection of [35S]methionine into the motor columns of normal; single lesioned (i.e., transection axotomy, amputation axotomy, or sham CL followed by amputation); and double-lesioned limb axons (i.e., nerve transection CL followed 2 weeks later by amputation axotomy). The rate of SCb transport in axons of unamputated newt limbs was 0.19 mm/day. There was an increase in the amount of labeled SCb proteins transported in axons regenerating as the result of a single lesion but no acceleration in the rate of SCb transport, which was 0.21 mm/day in axons that received a sham CL followed by limb amputation. The rate of SCb transport doubled (0.40 mm/day) and the amount of labeled SCb proteins being transported was increased when amputation was preceded by a CL. This study demonstrates that the earlier onset of limb regrowth, seen when amputation follows a CL, is associated with an increased transport of SCb proteins. This suggests that limb regeneration is, in part, regulated by axonal regrowth. We propose that the blastema requires a minimum quantity of innervation before progressing to the next stage of limb regeneration, and that the transport of SCb proteins determines when that quantity will be available. |
| Databáze: | OpenAIRE |
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