MYOGENESIS AND DNA SYNTHESIS

Paul Pietsch
Indiana University [1]

Adapted from J. Cell Biol. 19:56A (1963) [2], [3]

Note: much of what is presented below is amplified upon in the hyperlinks and the footnotes.

Studies here indicate that, during regeneration, myogenic cells are

These and other considerations stimulated thoughts that various levels of differentiation in skeletal muscle are only phenomenological and that myogenesis wherever found and whatever anatomical end point it reaches is controlled by the same intrinsic, basic events.

How, then, might one account for morphological variations among different musculatures?

It might be that the response to differentiate is detonated in events associated with DNA synthesis. (e.g., mitosis) Differentiation within a specific myogenic system, then, could depend simply on where and when DNA is synthesizing. A corollary of these speculations is that a particular myogenic system would have its own "profile" of DNA synthesis, changes in which would lead to alterations in morphogenesis.

This latter proposition was tested in regenerating Amblystoma larval limbs explanted in company with spinal cord [4].

Under the specified conditions ,[5] experimental limb tissues incorporated appreciably more thymidine-H³ than did controls[6] as measured by liquid scintillation counting. Muscle increased 40 percent, and morphogenesis underwent dramatic changes.

Differentiation of skeletal muscle and DNA synthesis thus seem linked by a common antecedent.

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pietsch@indiana.edu