Title

Ubiquitin and actin expression in claw muscles of land crab, Gecarcinus lateralis, and american lobster, Homarus americanus: Differential expression of ubiquitin in two slow muscle fiber types during molt-induced atrophy

Document Type

Journal Article

Publisher

International Association of Astacology

Faculty

Computing, Health and Science

School

Natural Sciences

RAS ID

4

Comments

Originally published as: Koenders, A., Yu, X., Chang, E. S., & Mykles, D. L. (2002). Ubiquitin and actin expression in claw muscles of land crab, Gecarcinus lateralis, and american lobster, Homarus americanus: Differential expression of ubiquitin in two slow muscle fiber types during molt‐induced atrophy. Journal of Experimental Zoology Part A: Ecological Genetics and Physiology, 292(7), 618-632. Original article available here

Abstract

The closer muscle of large-clawed decapod crustaceans undergoes a proecdysial (premolt) atrophy to facilitate withdrawal of the appendage at ecdysis. This atrophy involves the activation of both calcium-dependent (calpains) and ubiquitin (Ub)/proteasome-dependent proteolytic systems that break down proteins to reduce muscle mass. Moreover, the large slow-twitch (S1) fibers undergo a greater atrophy than the small slow-tonic (S2) fibers. Both polyUb mRNA and Ub-protein conjugates increase during claw muscle atrophy. In this study in situ hybridization and RT-PCR were used to determine the temporal and spatial expression of polyUb and α-actin. A cDNA encoding the complete sequence of lobster muscle α-actin was characterized; a probe synthesized from the cDNA provided a positive control for optimizing RT-PCR and in situ hybridization. PolyUb was expressed at low levels in claw closer muscle from anecdysial (intermolt) land crab. By early proecdysis (premolt; stage D0), polyUb mRNA levels increased in medial fibers that insert along the midline of the apodeme, with greater expression in S1 than S2, while levels remained low in peripheral fibers. By late proecdysis, polyUb mRNA decreased in central fibers, while mRNA increased in peripheral S1 fibers. In contrast, α-actin was expressed in lobster claw muscles at relatively constant levels during the intermolt cycle. These results suggest that Ub/proteasome-dependent proteolysis contributes to enhanced turnover of myofibrillar proteins during claw closer muscle atrophy. Furthermore, atrophy is not synchronous within the muscle; it begins in medial fibers and then progresses peripherally.

DOI

10.1002/jez.10081

 
COinS
 

Link to publisher version (DOI)

10.1002/jez.10081