Sox regulates transcription of the sea urchin arylsulfatase gene

A 50 bp region from - 194 bp to - 144 bp of the arylsulfatase gene (HpArs) of the sea urchin, Hemicentrotus pulcherrimus, is related to the temporally regulated expression of this gene. This region contains a Sox (Sry-related HMG box)-binding site, and the introduction of sequence mutations to this site significantly reduced the activity of the HpArs promoter, even in the presence of the C15 enhancer, which consists of HpOtx and CAAT motifs. A pr otein that binds to the Sox-binding site in the 50 bp region of the HpArs g ene was detected in nuclear extracts of mesenchyme blastulae and a protein synthesized in vitro using SoxB1 cDNA of another sea urchin, Strongylocentr otus purpuratus, also bound to this Sox site. These results suggest that Hp Sox, which is maternally expressed and remains abundant by the pluteus stag e, is clearly implicated in regulation of the HpArs gene. The presence of a negatively acting cis element in this 50 bp region has also been detected.