Left-right (LR) axis establishment during embryogenesis underlies the asymmetric body plan of adult animals, for example, the siting of the heart on the left side of the human body. On , Bunney et al. report that the signalling molecule 14-3-3E is involved very early in LR patterning in Xenopus laevis. The researchers show that the treatment of newly fertilised eggs with Fusiococcin-A, a fungal toxin that interacts with 14-3-3 proteins, randomised on which side of the body the heart, gut and gall bladder developed in the embryos, as did the blockade of 14-3-3 function with a phosphopeptide containing a 14-3-3 interaction motif and the overexpression of 14-3-3E. Their demonstration that 14-3-3E is asymmetrically localised at the first cell division of fertilised Xenopus eggs identifies the earliest LR asymmetric molecular localisation in any species to date.
