College of Agriculture 
   and Life Sciences
 Department of Nutritional Sciences
  Ronald E. Allen, Professor
   Tel: (520) 621-7
   Fax: (520) 621-1396
   Email: rallen@ag.arizona.edu
Education:
Texas A&M University, B.S., Animal Science, 1972
Iowa State University, Ph.D., Biochemistry, 1976
Principal Academic Activities:
Academic activities are primarily in undergraduate teaching in the Department of Animal Sciences and graduate student advising in the Nutritional Sciences Interdepartmental Graduate Program and the Physiological Sciences Graduate Program.
Research Activities:
Research centers around the regulation of skeletal muscle mass during growth, disease and aging. Some of the most important events that regulate skeletal muscle repair and growth are attributable to the activities of muscle precursor cells known as satellite cells. These cells exist in postnatal muscle and have the ability to divide and subsequently fuse with existing fibers. The result is the addition of a new nucleus to the growing fiber . During muscle regeneration, satellite cells proliferate, differentiate and fuse together to form new muscle fibers. The primary goal of my research program is to understand the regulation of satellite cell activity.
A variety of extracellular signaling molecules, primarily protein growth factors, have been found to govern satellite cell activities in cell culture systems and in living muscle. The most important classes of growth factors thus far are the insulin-like growth factors, fibroblast growth factors, transforming growth factor and hepatocyte growth factor/scatter factor. The presentation of one or more of these growth factors to satellite cells in muscle tissue and the ability of satellite cells to recognize and respond are altered during different physiological situations. Therefore, the ability of a satellite cell to "wake " from its dormant state, migrate to the site of injury, commence proliferation and eventually differentiate into a functional muscle fiber depends on the carefully orchestrated interactions of growth factors, their receptors, the extracellular matrix, and intracellular signal transduction pathways. We are only beginning to understand how the extracellular environment, as well as the intrinsic properties of satellite cells, change during growth, adulthood and old age.

Representative Publications:

Sheehan, S.M., and Allen, R.E. (1999). Skeletal Muscle Satellite Cell Proliferation in Response to Members of the Fibroblast Growth Factor Family and Hepatocyte Growth Factor. (submitted)

Davis, M.J., Smith, C.K., and Allen, R.E. (1999). Myogenin expression in mammalian muscle satellite cells in relation to IGF-I and/or TGF-b. (submitted).

Sheehan, S.M., and Allen, R.E. (1999). Skeletal Muscle Satellite Cell Proliferation in Response to Members of the Fibroblast Growth Factor Family and Hepatocyte Growth Factor.  J. Cell. Physiol. 181:499-506. 

Sheehan, S.M., Tatsumi, R., Temm-Grove, C.J., and Allen, R.E. (2000).  HGF is an autorcine growth factor for skeletal muscle satellite cells in vitro. Muscle and Nerve (in press).

 Tatsumi, R., Sheehan, S.M., Iwasaki, H., Hattori, A., and Allen, R.E. (Submitted 2000). Mechanical stretch induces activation of skeletal muscle satellite cells in vitro.  Exp. Cell Res.

 


Invited Presentations:

  • Invited seminar in Department of Animal Sciences, Penn State University, March 200

  • Invited seminar in Department of Anatomy and Cell Biology, University of Manitoba, April 2000

  • Invited seminar in Department of Physiology, University of Arizona, October 2000

  • Presented poster at Asilomar Conference on Molecular Biology of Muscle Development, May 2000

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