MicroRNA miR‐252 targets mbt to control the developmental growth of Drosophila

Abstract

Developmental growth is an intricate process involving the coordinated regulation of the expression of various genes, and microRNAs (miRNAs) play crucial roles in diverse processes throughout animal development. The ecdysone‐responsive miRNA, miR‐252, is normally upregulated during the pupal and adult stages of Drosophila development. Here, we found that overexpression of miR‐252 in the larval fat body decreased total tissue mass through a reduction in both cell size and cell number, causing a concomitant decrease in larval size. Furthermore, miR‐252 overexpression led to a delayed larval‐to‐pupal transition with defective anterior spiracle eversion, as well as a decrease in adult size and mass. Conversely, adult flies lacking miR‐252 showed an increase in mass compared with control flies. We found that miR‐252 directly targeted mbt, encoding a p21‐activated kinase, to repress its expression. Notably, co‐overexpression of mbt rescued the developmental and growth defects associated with miR‐252 overexpression, indicating that mbt is a biologically relevant target of miR‐252. Overall, our data support a role for the ecdysone/miR‐252/mbt regulatory axis in growth control during Drosophila development.

Profiling of MicroRNAs in Midguts of Plutella xylostella Provides Novel Insights Into the Bacillus thuringiensis Resistance

“…Pxy-miR-252 belonged to the miR-252 family. It has been found that miR-252 could directly repress the mbt expression to control the developmental growth of Drosophila ( Lim et al, 2019 ) and was also involved in dengue virus replication in Aedes albopictus ( Yan et al, 2014 ). Pxy-miR-274 was classified into the miR-274 family.…”

The conserved microRNA miR‐8‐3p coordinates the expression of V‐ATPase subunits to regulate ecdysone biosynthesis forDrosophilametamorphosis

“…To test the efficiency of RNAi lines for Vha knockdown, flies carrying either hs‐GAL4 only ( hs‐GAL4 /+) or both hs‐GAL4 and each of the experimental UAS‐RNAi transgenes ( hs > Vha‐RNAi ) were heat‐shocked at the wandering L3 stage at 37°C for 40 minutes and then cultured at 25°C for 36 hours prior to analysis. A flip‐out clonal assay was performed by crossing hsFLP; Actin > CD2 > GAL4 , UAS‐nlsGFP flies with the experimental UAS transgenic flies or w 1118 flies, as described previously 25 …”

“…Target sites for miRNA binding in the 3′‐UTR of the corresponding genes were assessed by a luciferase reporter assay as described previously 25 . Primer sets that were used to construct the luciferase reporters are listed in Table S4.…”

“…After puparium formation, defective anterior spiracle eversion was examined as described previously, 25 and the percentage of pupal death was determined by counting the empty pupal cases and dead flies after living adult flies were emptied from the vials.…”

“…For example, the expression of let‐7‐Complex miRNAs is induced by ecdysone signaling, and these miRNAs target abrupt and chinmo to control the distinct metamorphic processes 22-24 . In another ecdysone‐responsive miRNA, miR‐252, expression is upregulated during the pupal and adult stages of development, and it targets mbt to control the developmental growth 25 . However, a comprehensive understanding of metamorphosis‐associated miRNAs and their biologically relevant targets remains elusive.…”