tailieunhanh - Báo cáo khoa học: Characterization of the Drosophila Methoprene -tolerant gene product Juvenile hormone binding and ligand-dependent gene regulation

Juvenile hormones (JHs) of insects are sesquiterpenoids that regulate a great diversity of processes in development and reproduction. As yet the molecular modes of action of JH are poorly understood. TheMethoprene-tolerant (Met) gene of Drosophila melanogasterhas been found to be responsible for resistance to a JH analogue (JHA) insecticide, methoprene. Previous studies onMethave implicated its involvement in JH signaling, although direct evidence is lacking. | ềFEBS Journal Characterization of the Drosophila Methoprene-tolerant gene product Juvenile hormone binding and ligand-dependent gene regulation Ken Miura Masahito Oda Sumiko Makita and Yasuo Chinzei Department of MedicalZoology Schoolof Medicine Mie University Tsu City Japan Keywords juvenile hormone juvenile hormone receptor Methoprene-tolerant Drosophila transcription factor Correspondence K. Miura Department of MedicalZoology Schoolof Medicine Mie University Edobashi 2-174 Tsu514-8507 Japan Fax 81 59 231 5215 Tel 81 59 231 5013 E-mail k-miura@ Received 27 October 2004 revised 20 December 2004 accepted 4 January 2005 doi Juvenile hormones JHs of insects are sesquiterpenoids that regulate a great diversity of processes in development and reproduction. As yet the molecular modes of action of JH are poorly understood. The Methoprene-tolerant Met gene of Drosophila melanogaster has been found to be responsible for resistance to a JH analogue JHA insecticide methoprene. Previous studies on Met have implicated its involvement in JH signaling although direct evidence is lacking. We have now examined the product of Met MET in terms of its binding to JH and ligand-dependent gene regulation. In vitro synthesized MET directly bound to JH III with high affinity Kd nM mean SD consistent with the physiological JH concentration. In transient transfection assays using Drosophila S2 cells the yeast GAL4-DNA binding domain fused to MET exerted JH- or JHA-dependent activation of a reporter gene. Activation of the reporter gene was highly JH- or JHA-specific with the order of effectiveness JH III JH II JH I methoprene compounds which are only structurally related to JH or JHA did not induce any activation. Localization of MET in the S2 cells was nuclear irrespective of the presence or absence of JH. These results suggest that MET may function as a JH-dependent transcription factor. Insect development and reproduction are