Transcription factors FTZ-F1 and Blimp-1 control the pupal development and eclosion timing in Drosophila. Abdelrahman Sayed Sultan1*, Hitoshi Ueda1,2. 1) THE GRADUATE SCHOOL OF NATURAL SCIENCE AND TECHNOLOGY, OKAYAMA UNIVERSITY, OKAYAMA, JAPAN; 2) BIOLOGY DEPARTMENT, FACULTY OF SCIENCE, OKAYAMA UNIVERSITY, OKAYAMA, JAPAN.

   FTZ-F1 is a member of the nuclear hormone receptor, induced after ecdysone pulse and expressed transiently during the development. Blimp-1, an ecdysone inducible transcriptional repressor, binds to the promoter region of the ftz-f1 gene and plays an important role in determining the precise timing of ftz-f1 expression during prepupal period. We have shown that the temporally restricted expression of FTZ-F1 is important for prepupal development of Drosophila. We also have shown that FTZ-F1 is expressed throughout the pupal development, with especially high levels during late pupal stage and disappeared slightly before eclosion. However, the regulation mechanism and function of FTZ-F1 during the pupal development remain unknown. We examined effects of blimp-1 and ftz-f1 knockdown and over expression by using GAL4/UAS system. We found that blimp-1 knockdown in the whole body induces premature expression of FTZ-F1 and advancing of pupal development and eclosion timing. Interestingly, we also found that blimp-1 knockdown in fat body, an organ that retains endocrine and storage functions of vertebrate liver and adipose tissue, induces advancing of pupal development and eclosion timing. Moreover, blimp-1 over expression in fat body induces delaying of pupal development and delaying or inhibition of eclosion. On the other hand, ftz-f1 knockdown in fat body induces delaying of pupal development and advancing of eclosion timing. In conclusion, these results reveal that the expression of ftz-f1 is controlled by Blimp-1 and both of them control the pupal development and eclosion timing.