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.
Laboratoire d'Anatomie comparée, Université Paris VII, France.
J
J
Géraudie
J
J
Hourdry
S
S
Vriz
M
M
Singer
M
M
Méchali
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