HpSumf1 is involved in the activation of sulfatases responsible for regulation of skeletogenesis during sea urchin development.

Sulfatases such as arylsulfatase and heparan sulfate 6-O-endosulfatase play important roles in morphogenesis during sea urchin development. For the activation of these sulfatases, Cα-formylglycine formation by sulfatase modifying factor (Sumf) is required. In this study, to clarify the regulatory mechanisms for the activation of sulfatases during sea urchin development, we examined the expression and function of the Hemicentrotus pulcherrimus homologs of Sumf1 and Sumf2 (HpSumf1 and HpSumf2, respectively). Expression of HpSumf1 but not HpSumf2 mRNA was dynamically changed during early development. Functional analyses of recombinant HpSumf1 and HpSumf2 using HEK293T cells expressing mouse arylsulfatase A (ArsA) indicated that HpSumf1 and HpSumf2 were both able to activate mammalian ArsA. Knockdown of HpSumf1 using morpholino antisense oligonucleotides caused abnormal spicule formation in the sea urchin embryo. Injection of HpSumf2 mRNA had no effect on skeletogenesis, while injection of HpSumf1 mRNA induced severe supernumerary spicule formation. Taken together, these findings suggest that HpSumf1 is involved in the activation of sulfatases required for control of skeletogenesis.