An identical effect mediated by thyroid deficiency or oncogene v-erbA in the chick embryo.
We have shown earlier that the association of v-myc and v-erbA (MAHEVA construct) is responsible for the appearance of a specific phenotype in chick embryos inoculated at E3. This phenotype comprises rapidly growing heart rhabdomyomas (induced by v-myc alone) and within these tumors secondarily appearing cartilage nodules (Bachnou et al., Oncogene 6: 1041-1047, 1991). Here we report that v-erbA can be replaced by thyroid deficiency. When decapitated embryos were inoculated with virus MC29 (v-myc alone) or when v-myc inoculated embryos were treated with thiourea, 100% of the embryos reaching E17 to E19 displayed tumoral hearts bearing cartilage nodules. We thus report in vivo evidence that v-erbA acts by antagonizing the effects of thyroid hormones. Remarkably, thyroid deficiency rendered embryos more sensitive to the effect of v-myc, since 100% developed heart rhabdomyomas and cartilage nodules, versus about 70% affected when either v-myc or MAHEVA were inoculated. Thyroid deficiency did not alter the species-specific character of transdifferentiation, since only chick but not quail embryos developed cartilage nodules after thyroidectomy or MAHEVA infection.
Bachnou
N
N
Institut d'Embryologie Cellulaire et Moléculaire du CNRS et du College de France, Lille, France.
Saule
S
S
Dieterlen-Lievre
F
F
D000818:Animals; D002113:Calcification, Physiologic / Q000502:physiology; D002356:Cartilage / Q000166:cytology; D002454:Cell Differentiation / Q000502:physiology; D002642:Chick Embryo; D004625:Embryo, Nonmammalian / Q000502:physiology / Q000821:virology; D006338:Heart Neoplasms / Q000821:virology; D007037:Hypothyroidism / Q000503:physiopathology*; D009206:Myocardium / Q000166:cytology; D016274:Oncogene Protein p55(v-myc) / Q000378:metabolism / Q000502:physiology; D018774:Oncogene Proteins v-erbA / Q000378:metabolism / Q000502:physiology*; D010641:Phenotype; D011784:Quail / Q000196:embryology / Q000378:metabolism; D012208:Rhabdomyosarcoma / Q000821:virology; D013890:Thiourea / Q000494:pharmacology
D016274:Oncogene Protein p55(v-myc); D018774:Oncogene Proteins v-erbA; D013890:Thiourea