N-ACETYL-CYSTEINE CAUSES A LATE RE-SPECIFICATION OF THE ANTEROPOSTERIOR AXIS IN THE XENOPUS EMBRYO

N-acetyl cysteine is an agent which has been shown to interrupt signal transduction processes linking a wide range of stimuli to the activat ion of NF-KB in mammalian cells. We have investigated its effect on th e early development of Xenopus embryos by injecting it into blastulae, using concentrations comparable to those effective on cultured cells. High concentrations at the late blastula or early gastrula stage supp ress posterior and enhance anterior development, yielding embryos with enlarged cement glands and otherwise consisting of little except head in extreme cases. Reducing the amount of N-acetyl cysteine injected l eads to progressively more posterior structures developing. Injection into one- or two-cell embryos gives similar phenotypes, but of reduced severity and the cement gland is not so enlarged, Explants of animal cap cells taken several hours after injection develop to give large am ounts of cement gland material. We have examined the expression of a n umber of genes in the anteriorised embryos. Posterior markers and Xsna are reduced. Noggin and Goosecoid mRNA are up-regulated through the g astrula and persist at these levels until at least the late neurula st age, whereas in controls Noggin is much lower and Goosecoid is absent at these stages. The most anteriorised phenotype may be a consequence of this changed expression. (C) 1996 Wiley-Liss, Inc.