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Myogenin, MyoD, and myosin heavy chain isoform expression following hindlimb suspension.
Aviat Space Environ Med. 1999 May; 70(5):511-6.AS

Abstract

BACKGROUND

Myogenin expression is associated with a slow myofiber phenotype, and MyoD expression is associated with a fast myofiber phenotype. Hindlimb suspension (HS) will induce muscular atrophy, and a transition from a slow to fast myofiber phenotype in the rat soleus.

HYPOTHESIS

Hindlimb suspension will induce myofiber atrophy, and a slow to fast myofiber type transition with corresponding changes in myogenin and MyoD expression.

METHODS

Myofiber phenotype was evaluated by electrophoretically separating the myosin heavy chain isoforms. Myogenin expression was evaluated by Northern analysis, while MyoD expression was evaluated by Northern analysis and semiquantitative RT-PCR.

RESULT

After 28 d of hindlimb suspension, there was significantly (p < 0.05) less myosin heavy chain Type IIA, and more (p < 0.05) myosin heavy chain Type IIX in the soleus muscles of hindlimb suspended rats compared with soleus muscles from weight-bearing (WB) rats. Although there was a shift to a faster myosin heavy chain phenotype in soleus muscles from hindlimb suspended rats, there was no change in myogenin expression, and MyoD expression was undetectable by Northern analysis. Semi-quantitative RT-PCR revealed an up-regulation of MyoD expression following 14 d of hindlimb suspension.

CONCLUSIONS

Myogenin expression levels do not change during the slow to fast myofiber phenotypic transition that occurs during hindlimb suspension; MyoD expression appears to increase at the same time as the phenotypic transition. Thus, MyoD expression or the Myogenin: MyoD mRNA ratio may be important in the phenotypic transition. Neither myogenin nor MyoD appear to play a critical role in the muscular atrophy that occurs during weightlessness.

Authors+Show Affiliations

Department of Anatomy, University of Wisconsin, Madison, USA.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

10332949

Citation

Mozdziak, P E., et al. "Myogenin, MyoD, and Myosin Heavy Chain Isoform Expression Following Hindlimb Suspension." Aviation, Space, and Environmental Medicine, vol. 70, no. 5, 1999, pp. 511-6.
Mozdziak PE, Greaser ML, Schultz E. Myogenin, MyoD, and myosin heavy chain isoform expression following hindlimb suspension. Aviat Space Environ Med. 1999;70(5):511-6.
Mozdziak, P. E., Greaser, M. L., & Schultz, E. (1999). Myogenin, MyoD, and myosin heavy chain isoform expression following hindlimb suspension. Aviation, Space, and Environmental Medicine, 70(5), 511-6.
Mozdziak PE, Greaser ML, Schultz E. Myogenin, MyoD, and Myosin Heavy Chain Isoform Expression Following Hindlimb Suspension. Aviat Space Environ Med. 1999;70(5):511-6. PubMed PMID: 10332949.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Myogenin, MyoD, and myosin heavy chain isoform expression following hindlimb suspension. AU - Mozdziak,P E, AU - Greaser,M L, AU - Schultz,E, PY - 1999/5/20/pubmed PY - 1999/5/20/medline PY - 1999/5/20/entrez KW - NASA Discipline Cell Biology KW - Non-NASA Center SP - 511 EP - 6 JF - Aviation, space, and environmental medicine JO - Aviat Space Environ Med VL - 70 IS - 5 N2 - BACKGROUND: Myogenin expression is associated with a slow myofiber phenotype, and MyoD expression is associated with a fast myofiber phenotype. Hindlimb suspension (HS) will induce muscular atrophy, and a transition from a slow to fast myofiber phenotype in the rat soleus. HYPOTHESIS: Hindlimb suspension will induce myofiber atrophy, and a slow to fast myofiber type transition with corresponding changes in myogenin and MyoD expression. METHODS: Myofiber phenotype was evaluated by electrophoretically separating the myosin heavy chain isoforms. Myogenin expression was evaluated by Northern analysis, while MyoD expression was evaluated by Northern analysis and semiquantitative RT-PCR. RESULT: After 28 d of hindlimb suspension, there was significantly (p < 0.05) less myosin heavy chain Type IIA, and more (p < 0.05) myosin heavy chain Type IIX in the soleus muscles of hindlimb suspended rats compared with soleus muscles from weight-bearing (WB) rats. Although there was a shift to a faster myosin heavy chain phenotype in soleus muscles from hindlimb suspended rats, there was no change in myogenin expression, and MyoD expression was undetectable by Northern analysis. Semi-quantitative RT-PCR revealed an up-regulation of MyoD expression following 14 d of hindlimb suspension. CONCLUSIONS: Myogenin expression levels do not change during the slow to fast myofiber phenotypic transition that occurs during hindlimb suspension; MyoD expression appears to increase at the same time as the phenotypic transition. Thus, MyoD expression or the Myogenin: MyoD mRNA ratio may be important in the phenotypic transition. Neither myogenin nor MyoD appear to play a critical role in the muscular atrophy that occurs during weightlessness. SN - 0095-6562 UR - https://www.unboundmedicine.com/medline/citation/10332949/Myogenin_MyoD_and_myosin_heavy_chain_isoform_expression_following_hindlimb_suspension_ DB - PRIME DP - Unbound Medicine ER -