Denervation‐induced changes in soluble protein content during forelimb regeneration in the adult newt, Notophthalmus viridescens

Abstract

Denervation-induced alterations in the composition of the soluble protein population of various stages of forelimb regenerates in the adult newt were examined. Denervation alters the normal protein arrays in three ways: (1) proteins may be eliminated from an array, (2) proteins not normally present in an array may be induced to appear, and (3) proteins unique to d e nervated regenerates may appear in an array. The character of the denervationinduced alteration at five days post-amputation is basically different from that at later stages of regeneration. The stages during which the regenerate is b e coming independent of the nerve for its morphogenetic activity are the ones in which the protein profiles are the most drastically altered. Morphogenetic independence of the nerve therefore does not require the synthesis of nerve dependent proteins, and it is concluded that nerve independence is a property generated by the production of a critical number of blastema cells. Nerve dependent proteins are required for the mitotic activity which leads to attainment of the critical mass, and the failure of denervated early regenerates to continue regeneration may be due solely to mitotic inhibition.

Limb regeneration in higher vertebrates: Developing a roadmap

“…The AEC induces ectopic regenerative outgrowths in much the same manner an ectopic AER induces ectopic outgrowth of the limb bud (Thornton and Thornton, 1965;Saunders et al, 1976). Removal of the AER from a limb bud results in the inhibition of limb outgrowth, and removal of the AEC similarly inhibits the regenerative response (Dearlove and Stocum, 1974;Saunders, 1998). One major difference between the AER and the AEC is that the AEC readily regenerates, whereas the AER is nonregenerative.…”

Mechanisms of urodele limb regeneration

“…Neural and hormonal input to cultured adult newt limb blastemas maintains DNA and protein synthesis by the blastema cells (Vethamany‐Globus, Globus, & Tomlinson, 1978). The protein profile changes throughout blastema growth and differentiation (Dearlove & Stocum, 1974; Singer, 1978; Singer & Ilan, 1977; Tsonis, Mescher, & Del‐Rio Tsonis, 1992). Changes in protein synthesis are reflected in the ECM, particularly in the synthesis of proteoglycan and collagen‐associated glycosaminoglycans.…”

Novel Insights into the Flexibility of Cell and Positional Identity during Urodele Limb Regeneration

“…In subsequent days, this wound epidermis thickens to form the apical epidermal cap (AEC), which is molecularly and functionally similar to the apical ectodermal ridge (AER) of the developing limb bud (Saunders 1948;Christensen and Tassava 2000). For example, the AEC is essential for outgrowth of the regenerating limb because removal of the AEC or replacement of this specialized epithelium by mature skin blocks regeneration (Dearlove and Stocum 1974;Mescher 1976;Tassava and Garling 1979). Furthermore, the AEC expresses those factors found in the embryonic AER such as mitogens of the fibroblast growth factor (FGF) family, including FGF-1 and FGF-2 (Boilly et al 1991;Mullen et al 1996;Christensen et al 2002;Dungan et al 2002).…”