Structure and Function of a Sea Urchin Orthodenticle-Related Gene (HpOtx)

AbstractTwo distinct types of orthodenticle-related proteins (HpOtxE/L) have been implicated as transcription activators of the aboral ectoderm-specific arylsulfatase (Ars) gene. Here, we describe the structure of HpOtx gene and present evidence that mRNAs ofHpOtxE/Lare transcribed from a single HpOtx gene by altering the transcription start site and by alternative splicing. By transactivation experiments, we have also demonstrated that HpOtxLactivates theArspromoter in the gastrula-stage embryo