Polyadenylate-binding proteins are essential for the molting development of locusts

Abstract

Polyadenylate-binding proteins (PABPs) are critical for mRNA stability, translation, and decay in eukaryotes. However, their specific roles in regulating molt-related gene stability in insects remain unclear. Here, we characterize two PABP genes, LmPABP1 and LmPABP2, in the migratory locust, Locusta migratoria. Phylogenetic analysis revealed LmPABP1 as a cytoplasmic PABP (PABPC) and LmPABP2 as a nuclear PABP (PABPN). Tissue-specific expression profiling showed that LmPABP1 is highly expressed in the integument and gut during the fifth instar, while LmPABP2 expression exhibits stage-specific fluctuations. RNA interference-mediated knockdown of LmPABP1 caused 100% mortality in both fourth- and fifth-instar nymphs, whereas silencing LmPABP2 led to varied mortality during pre-, mid-, and post-molting stages. Histological analysis showed disrupted cuticle dissolution in LmPABP1-silenced locusts and delayed dissolution in LmPABP2-depleted individuals. Critically, LmPABP1 knockdown significantly downregulated key chitin metabolism genes (LmCht5, LmCht10, and LmUAP1). Furthermore, actinomycin D treatment confirmed that LmPABP1 silencing accelerates decay of LmCht5 and LmCht10 mRNAs, indicating its essential role in mRNA stabilization. This study delineates the functional divergence of cytoplasmic LmPABP1 and nuclear LmPABP2 in post-transcriptional regulation, specifically stabilizing chitinase mRNAs during locust molting, offering potential molecular targets for developing novel pest control strategies.