In insects,20-hydroxyecdysone(20E)limits systemic growth by triggering developmental transitions.Previous studies have shown that 20E-induced let-7 exhibits crosstalk with the cell cycle.Here,we examined the underlyin...In insects,20-hydroxyecdysone(20E)limits systemic growth by triggering developmental transitions.Previous studies have shown that 20E-induced let-7 exhibits crosstalk with the cell cycle.Here,we examined the underlying molecular mechanisms and physiological functions of 20E-induced let-7 in the fat body,an organ for energy storage and nutrient mobilization which plays a critical role in the larval growth.First,the overexpression of let-7 decreased the body size and led to the reduction of both nucleolus and cell sizes in the larval fat body.In contrast,the overexpression of let-7-Sponge increased the nucleolus and cell sizes.Moreover,we found that cdc7,encoding a conserved protein kinase that controls the endocycle,is a target of let-7.Notably,the mutation of cdc7 in the fat body resulted in growth defects.Overall,our findings revealed a novel role of let-7 in the control of endoreduplication-related growth during larval-prepupal transition in Drosophila.展开更多
基金supported by the National Science Foundation of China(31802010 and 31702054)to Xiao-Ling Xia and Suiting Liu,the Natural Science Foundation of Guangdong Province(2019A1515011899)to Su-Ning Liu.
文摘In insects,20-hydroxyecdysone(20E)limits systemic growth by triggering developmental transitions.Previous studies have shown that 20E-induced let-7 exhibits crosstalk with the cell cycle.Here,we examined the underlying molecular mechanisms and physiological functions of 20E-induced let-7 in the fat body,an organ for energy storage and nutrient mobilization which plays a critical role in the larval growth.First,the overexpression of let-7 decreased the body size and led to the reduction of both nucleolus and cell sizes in the larval fat body.In contrast,the overexpression of let-7-Sponge increased the nucleolus and cell sizes.Moreover,we found that cdc7,encoding a conserved protein kinase that controls the endocycle,is a target of let-7.Notably,the mutation of cdc7 in the fat body resulted in growth defects.Overall,our findings revealed a novel role of let-7 in the control of endoreduplication-related growth during larval-prepupal transition in Drosophila.
