Enhanced c-myc gene expression during forelimb regenerative outgrowth in the young Xenopus laevis.
Analysis of the expression of the c-myc protooncogene has been carried out in the forelimb regenerate of the Xenopus laevis froglet. Northern blot hybridization analysis revealed the presence of a 2.5-kilobase c-myc transcript in the regenerate forelimb at a level at least 7-fold more than the one found in nonregenerating forelimbs or stumps of regenerating forelimbs. In situ hybridization analyses confirmed the relative abundance of c-myc RNA in the regenerate forelimb and provided evidence of spatial localization of high levels of c-myc RNA in specific cell layers. The deepest layers of the wound epithelium of epidermal origin showed a strong signal, whereas virtually no c-myc RNA was detected in the outermost layers. Labeling was also observed in mesenchymal cells of the blastema where it was relatively evenly distributed. This pattern of c-myc RNA in the regenerate might indicate that the expression of c-myc plays a role in the regulation of the continued proliferation of specific cells of the regenerate, whereas repression of this gene in the epidermis correlates with terminal differentiation of keratinocytes.
Géraudie
J
J
Laboratoire d'Anatomie comparée, Université Paris VII, France.
Hourdry
J
J
Vriz
S
S
Singer
M
M
Méchali
M
M
D000671:Amputation, Surgical; D000818:Animals; D015152:Blotting, Northern; D004848:Epithelium / Q000648:ultrastructure; D005552:Forelimb; D015870:Gene Expression; D008854:Microscopy, Electron; D009693:Nucleic Acid Hybridization; D011505:Protein-Tyrosine Kinases / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D016271:Proto-Oncogene Proteins c-myc; D011519:Proto-Oncogenes; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D015347:RNA Probes; D016372:RNA, Antisense; D012333:RNA, Messenger / Q000037:antagonists & inhibitors; D012038:Regeneration; D014947:Wounds and Injuries / Q000473:pathology; D014982:Xenopus laevis
D011518:Proto-Oncogene Proteins; D016271:Proto-Oncogene Proteins c-myc; D015347:RNA Probes; D016372:RNA, Antisense; D012333:RNA, Messenger; D012313:RNA; D011505:Protein-Tyrosine Kinases