H. Ellingerziegelbauer et C. Dreyer, THE PATTERN OF RETINOIC ACID RECEPTOR-GAMMA (RAR-GAMMA) EXPRESSION INNORMAL DEVELOPMENT OF XENOPUS-LAEVIS AND AFTER MANIPULATION OF THE MAIN BODY AXIS, Mechanisms of development, 41(1), 1993, pp. 33-46
Nuclear receptors are a prerequisite for the transduction of retinoid
signals in vertebrate embryogenesis. We have raised an antiserum again
st the X. laevis retinoic acid receptor gamma (xRARgamma), which speci
fically detects a polypeptide with an M(r) of 54 X 10(3) in embryos at
gastrula and neurula stages. The antiserum reveals xRARgamma as a nuc
lear protein in the head endomesoderm, the neuroectoderm of the hindbr
ain region, and the entire posterior region during neurula stages. Exp
lanted animal caps express low amounts of xRARgamma in the absence of
mesoderm induction. Treatment of animal caps with activin leads to an
increase of the amount and to a regionalization of the xRARgamma expre
ssion. In exogastrulae and in Keller sandwiches, the pattern of expres
sion in the endomesoderm is as expected by analogy to the normal embry
o and therefore independent of the vertical contact between the germ l
ayers. A planar signal coming from the dorsal mesoderm is sufficient t
o impose region-specific expression of xRARgamma in the neuroectoderm
of Keller sandwiches.