Tcf7l1 promotes transcription of Kruppel-like factor 4 during Xenopus embryogenesis

Kruppel-like factor 4 (Klf4) is a zinc finger transcription factor and plays crucial roles in Xenopus embryogenesis. However, its regulation during embryogenesis is still unclear. Here, we report that Tcf7l1, a key downstream transducer of the Wnt signaling pathway, could promote Klf4 transcription and stimulate Klf4 promoter activity in early Xenopus embryos. Furthermore, cycloheximide treatment showed a direct effect on Klf4 transcription facilitated by Tcf7l1. Moreover, the dominant negative form of Tcf7l1 (dnTcf7l1), which lacks N-terminus of the β-catenin binding motif, could still activate Klf4 transcription, suggesting that this regulation is Wnt/β-catenin independent. Taken together, our results demonstrate that Tcf7l1 lies upstream of Klf4 to maintain its expression level during Xenopus embryogenesis.