The composition of myofibrillar protein isoforms is a major determinant of a muscle's functional properties. Different isoforms are characteristic of a particular muscle type and isoform switching can occur as a result of disuse, training, or disease. Such changes in protein composition are often accompanied by structural remodeling of the myofibrils. This study will use the lobster claw-closer muscles as a model to understand the processes involved in isoform switching and myofibrillar remodeling. During juvenile development, the muscle fibers of the lobster claw undergo a predictable transformation from slow to fast fibers and vice versa, in the same animal. Isoform-specific probes will be used with Northern blots and in situ hybridization to study the exact timing of isoform switching. Next, standard molecular and microscopic techniques will be used to study isoform gene expression, protein composition, and ultrastructural organization of single transforming muscle fibers. Finally, direct electrical stimulation will be used to experimentally manipulate these processes. The long term goal of this study is to understand how regulatory factors, such as myogenin and MyoD, control the processes involved in muscular plasticity.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Postdoctoral Individual National Research Service Award (F32)
Project #
1F32AR008597-01A1
Application #
6208073
Study Section
Special Emphasis Panel (ZRG1-SSS-3 (04))
Program Officer
Lymn, Richard W
Project Start
2000-09-01
Project End
Budget Start
2000-09-01
Budget End
2001-08-30
Support Year
1
Fiscal Year
2000
Total Cost
$37,516
Indirect Cost
Name
Colorado State University-Fort Collins
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
112617480
City
Fort Collins
State
CO
Country
United States
Zip Code
80523
Medler, Scott; Lilley, Travis R; Riehl, Jocelyn H et al. (2007) Myofibrillar gene expression in differentiating lobster claw muscles. J Exp Zool A Ecol Genet Physiol 307:281-95
Medler, Scott; Chang, Ernest S; Mykles, Donald L (2007) Muscle-specific calpain is localized in regions near motor endplates in differentiating lobster claw muscles. Comp Biochem Physiol A Mol Integr Physiol 148:591-8
Medler, Scott; Brown, Kitty J; Chang, Ernest S et al. (2005) Eyestalk ablation has little effect on actin and myosin heavy chain gene expression in adult lobster skeletal muscles. Biol Bull 208:127-37
Medler, Scott; Lilley, Travis; Mykles, Donald L (2004) Fiber polymorphism in skeletal muscles of the American lobster, Homarus americanus: continuum between slow-twitch (S1) and slow-tonic (S2) fibers. J Exp Biol 207:2755-67
Medler, Scott; Mykles, Donald L (2003) Analysis of myofibrillar proteins and transcripts in adult skeletal muscles of the American lobster Homarus americanus: variable expression of myosins, actin and troponins in fast, slow-twitch and slow-tonic fibres. J Exp Biol 206:3557-67
Medler, Scott (2002) Comparative trends in shortening velocity and force production in skeletal muscles. Am J Physiol Regul Integr Comp Physiol 283:R368-78
Mykles, Donald L; Medler, Scott; Koenders, Annette et al. (2002) Myofibrillar protein isoform expression is correlated with synaptic efficacy in slow fibres of the claw and leg opener muscles of crayfish and lobster. J Exp Biol 205:513-22