GENES FOR DROSOPHILA SMALL HEAT-SHOCK PROTEINS ARE REGULATED DIFFERENTLY BY ECDYSTERONE

被引:23
作者
AMIN, J
MESTRIL, R
VOELLMY, R
机构
[1] UNIV MIAMI,SCH MED,DEPT BIOCHEM & MOLEC BIOL,MIAMI,FL 33101
[2] GERMAN CANC RES CTR,W-6900 HEIDELBERG,GERMANY
关键词
D O I
10.1128/MCB.11.12.5937
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Genes for small heat shock proteins (hsp27 to hsp22) are activated in late third-instar larvae of Drosophila melanogaster in the absence of heat stress. This regulation has been simulated in cultured Drosophila cells in which the genes are activated by the addition of ecdysterone. Sequence elements (HERE) involved in ecdysterone regulation of the hsp27 and hsp23 genes have been defined by transfection studies and have recently been identified as binding sites for ecdysterone receptor. We report here that the hsp27 and hsp23 genes are regulated differently by ecdysterone. The hsp27 gene is activated rapidly by ecdysterone, even in the absence of protein synthesis. In contrast, high-level expression of the hsp23 gene begins only after a lag of about 6 h, is dependent on the continuous presence of ecdysterone, and is sensitive to low concentrations of protein synthesis inhibitors. Transfection experiments with reporter constructs show that this difference in regulation is at the transcriptional level. Synthetic hsp27 or hsp23 HERE sequences confer hsp27- or hsp23-type ecdysterone regulation on a basal promoter. These findings indicate that the hsp27 gene is a primary, and the hsp23 gene is mainly a secondary, hormone-responsive gene. Ecdysterone receptor is implied to play a role in the regulation of both genes.
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页码:5937 / 5944
页数:8
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