Activation of the Sarcophaga lectin gene promoter by (A+T)-stretch bindingprotein

Previously, we purified and isolated a cDNA for (A + T)-stretch binding pro tein (ATBP) that binds to (A + T)-stretches in the 5' upstream region of th e Sarcophaga lectin gene [Nakanishi-Matsui, M., Kubo, T. & Natori, S. (1995 ) fur: J. Biochem. 230, 396-400]. Here, we used a luciferase reporter to ex amine the effect of ATBP on transcription of the Sarcophaga lectin gene. De letion experiments revealed that ATBP activates the Sarcophaga lectin gene in a 5' upstream sequence-dependent manner, and that at least the N-termina l 25 residues, the three Zn-finger domains, an acidic domain and the third hydrophobic domain of ATBP are indispensable for its function. Furthermore, a synergistic effect was detected between ATBP and Dif, suggesting that AT BP is involved in the activation of insect immunity genes.