Efficient hormone-inducible protein function in Xenopus laevis.
A major problem in analyzing gene function during Xenopus development has been the inability to induce gene expression in a temporally controlled manner. We have attempted to solve this problem with a system of hormone-activated protein function, using the myogenic gene MyoD as a paradigm. We show that microinjection of RNA for MyoD fused to the ligand-binding domain of either the estrogen or glucocorticoid receptor results in hormone-dependent activation of MyoD function, as assayed by ectopic induction of muscle-specific actin mRNA. Induction is tightly regulated in both isolated animal caps and intact embryos, with ectopic muscle-specific actin expression inducible after 2 hr of hormone treatment. Higher levels of MyoD-receptor fusion proteins that native MyoD protein are present in embryos, apparently a result of increased fusion protein stability. This is the first demonstration that hormone-inducible fusion proteins can work effectively in a complex embryo.
Kolm
P J
PJ
Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge 02142, USA.
Sive
H L
HL
D000818:Animals; D004625:Embryo, Nonmammalian; D004967:Estrogens / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D005938:Glucocorticoids / Q000502:physiology; D017570:MyoD Protein / Q000235:genetics* / Q000378:metabolism; D011960:Receptors, Estrogen / Q000235:genetics* / Q000378:metabolism; D011965:Receptors, Glucocorticoid / Q000235:genetics* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014982:Xenopus laevis
D004967:Estrogens; D005938:Glucocorticoids; D017570:MyoD Protein; D011960:Receptors, Estrogen; D011965:Receptors, Glucocorticoid; D011993:Recombinant Fusion Proteins