Animal Cap Assay for TGF-β Signaling

TGF-β signals regulate a variety of processes during early vertebrate development, from stem cell maintenance and differentiation to tissue patterning and organogenesis. Detailed understanding of how this signaling pathway operates and what genes control activities of the signaling components of the pathway is therefore important for us to comprehend temporal- and tissue-specific TGF-β functions in vertebrate embryogenesis. Xenopus model system has been employed extensively in research on TGF-β signals, and much insight about TGF-β signaling mechanisms has been gained from these studies. Besides using whole embryos, explants from the ectodermal region of Xenopus, also known as animal caps, are used widely in investigations of the activities of an array of signal transducers as well as regulators of the pathway. This chapter introduces methods for dissection of animal caps and analyses of TGF-β signaling effects on animal caps.