Expression and subcellular localization of X-ATM during early Xenopus development

ATM, the gene mutated in ataxia telangiectasia, is a protein essential for handling DNA strand breaks. We recently isolated the Xenopus homologue of A TM, X-ATM and we report here the detailed expression pattern of the protein and the mRNA during early Xenopus development. During the cleavage stages, ATM protein was concentrated in and around the nuclei of all cells with lo w levels of expression also detected in the cytoplasm. Following neurulatio n, increased protein levels were detected in the nuclei of developing somit es and in the central nervous system. Areas of high protein expression corr elated with areas of increased mRNA expression which was detected in the nu clei of somites and the developing lens.