RUNXs are important transcription factors, which are involved in animal development and human carcinogenesis. RNT-1, the only homologue of RUNXs, in Caenorhabditis elegans (C. elegans) has been identified and viable mutant animals of
rnt-1 gene have been isolated and characterized recently. Genetic analyses using
rnt-1 mutants have shown that RNT-1 is regulated by TGFbeta- and Wnt-signaling pathways in the body size regulation and male tail development. Here, we review our current understanding of RNT-1 functions in these signaling pathways. Furthermore, future prospects of RNT-1 and BRO-1 studies in C. elegans are discussed in this review. (c) 2005 Wiley-Liss, Inc.