Melanophore differentiation in Xenopus laevis, with special reference to dorsoventral pigment pattern formation

Development ◽  
1983 ◽  
Vol 75 (1) ◽  
pp. 141-150
Author(s):  
Kojune Ohsugi ◽  
Hiroyuki Ide
Keyword(s):  
Pattern Formation ◽  
Xenopus Laevis ◽  
Special Reference ◽  
Epidermal Layer ◽  
Ventral Region ◽  
Electron Microscopic ◽  
Pigment Pattern ◽  
Ventral Skin

During the development of Xenopus laevis, after stage 26, a large number of dopa-positive cells were observed in the ventral region. Electron microscopic observations revealed that these cells became localized in the epidermal layer and contained premelanosomes. In cultured ventral skin, fully matured melanophores appeared. These results strongly suggest that a large number of melanoblasts are present in the ventral epidermis and remain there without final differentiation into melanized melanophores. Thus the positional difference of melanoblasts differentiation mainly contributes to dorsoventral pigment pattern formation of Xenopus laevis.

Axial organization of the regenerating limb: asymmetrical behaviour following skin transplantation

Development ◽  
1982 ◽  
Vol 70 (1) ◽  
pp. 197-213
Author(s):  
M. Maden ◽  
K. Mustafa
Keyword(s):  
Pattern Formation ◽  
Lower Limb ◽  
High Frequency ◽  
Skin Grafting ◽  
Good Frequency ◽  
Skin Transplantation ◽  
Serial Sectioning ◽  
Whole Mount ◽  
Ventral Skin ◽  
Anterior Posterior

An extensive series of skin grafting operations has been performed to investigate axial organization in the regenerating axolotl limb. Semicircular cuffs of skin from either anterior, posterior, dorsal or ventral surfaces were exchanged between right and left limbs thereby creating limbs with double anterior, double posterior, double dorsal or double ventral skin, all with normal internal tissues. Both fore and hindlimbs were used at both upper and lower limb levels. Following amputation through the grafted region the resulting regenerates were analysed both by whole-mount cartilage staining to observe the pattern of digits and by serial sectioning to observe the pattern of muscles. There were clear asymmetries in ability to produce duplications - posterior to anterior grafts resulted in a consistently high frequency of digital duplications, whereas anterior to posterior grafts produced very few. Similarly, dorsal to ventral grafts resulted in a good frequency of muscle duplications, whereas ventral to dorsal grafts did not. Such asymmetrical behaviour is not predicted by most models involving local cell:cell interactions and the significance of the results for theories of pattern formation is discussed.

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