Role of the LIM class homeodomain protein Xlim-1 in neural and muscle induction by the Spemann organizer in Xenopus

摘要: LIKE all known LIM class homeobox genes, Xlim-1 encodes a protein with two tandemly repeated cysteine-rich domains upstream of the homeodomain1. In Xenopus laevis, is specifically expressed in Spemann organizer, whose major functions include neural induction and dorsalization ventral mesoderm2–4. From RNA injection experiments we conclude here that: (1) behave as negative regulatory domains; (2) domain mutants elicited differentiation animal explants; (3) mutant, to lesser extent wild-type, enhanced muscle formation after connection Xbra; (4) both these activities are mediated by extracellular signals seen combined explant experiments; (5) activated goosecoid (gsc) expression explants, but not noggin or follistatin; (6) mutant partial secondary axes, cooperated gsc notochord formation. Thus has latent activities, implicating it organizer functions.