FIGURE 4.

Putative roles of HSKS in early Xenopus development.The contribution of HSKS to tissue hydration in Xenopus tadpoles is schematically represented. Accumulated HSKS in extra cellular matrix retains water, which may help otic vesicles and notochord vacuoles to swell. HSKS is enriched inside otic vesicles (Figure 1D), but outside of the notochord (Figure 1E), implying that aquaporin transports water from the extracellular space to intracellular vacuoles. Our results demonstrate that tissue-specifically expressed chst genes drive HSKS biosynthesis for normal development.