Transcriptome analysis of Spodoptera frugiperda Sf9 cells reveals putative apoptosis-related genes and a preliminary apoptosis mechanism induced by azadirachtin

Abstract

As an important botanical pesticide, azadirachtin demonstrates broad insecticidal activity against many agricultural pests. The results of a previous study indicated the toxicity and apoptosis induction of azadirachtin in Spodoptera frugiperda Sf9 cells. However, the lack of genomic data has hindered a deeper investigation of apoptosis in Sf9 cells at a molecular level. In the present study, the complete transcriptome data for Sf9 cell line was accomplished using Illumina sequencing technology, and 97 putative apoptosis-related genes were identified through BLAST and KEGG orthologue annotations. Fragments of potential candidate apoptosis-related genes were cloned, and the mRNA expression patterns of ten identified genes regulated by azadirachtin were examined using qRT-PCR. Furthermore, Western blot analysis showed that six putative apoptosis-related proteins were upregulated after being treated with azadirachtin while the protein Bcl-2 were downregulated. These data suggested that both intrinsic and extrinsic apoptotic signal pathways comprising the identified potential apoptosis-related genes were potentially active in S. frugiperda. In addition, the preliminary results revealed that caspase-dependent or caspase-independent apoptotic pathways could function in azadirachtin-induced apoptosis in Sf9 cells.

Pro-Apoptotic Function Analysis of the Reaper Homologue IBM1 in Spodoptera frugiperda

“…These results indicated that Sf-IBM1 activated the caspase-dependent pathway and induced apoptosis. IAPs contain the evolutionarily conserved BIR domains and the C-terminal RING finger, which display the activity of E3 ubiquitin ligase and play critical roles in apoptosis regulation by interacting with caspases and inhibiting the activities [38,39]. As is known, the RHG family proteins inhibit the function of DIAP1.…”

“…A transcriptome of Sf9 cells was performed, and the putative apoptosis-related genes were identified through BLAST and KEGG orthologue annotations in our previous study [39]. For the blast research, the threshold of E-value of 1e −5 was used, and a sequence with 285 bp length showed the 8 e−118 with the IBM1 from L. dispar (NM_001166341.1) was annotated as Sf-IBM1.…”

A Novel Insecticidal Molecule Extracted from Alpinia galanga with Potential to Control the Pest Insect Spodoptera frugiperda

“…Apoptosis is regulated by multiple proteins, such as caspases, inhibitors of apoptosis proteins (IAP) (including IAP, IAP-2, Survivin and Survivin-1), IAP antagonist proteins (including IBM1 and Grim-19), anti-apoptotic proteins (including DnaJ1 and TCTP), pro-apoptotic proteins (including Cathepsin B and Cathepsin L), p53 protein, etc. [ 37 ]. Among these proteins, caspases (Cysteinyl aspartate specific proteinase) form a family of cysteine proteases playing important roles in programmed cell death and can be classified, according to their biological functions, into two groups—initiator and effector caspases [ 38 ].…”

Cytotoxic and Apoptotic Activity of the Novel Harmine Derivative ZC-14 in Sf9 Cells

“…The releasing of cytochrome c also could be achieved through the pores formed by the large channels constituted with the oligomerization of Bax and Bak [ 37 ]. The activation of caspase cascades depended on the apoptosome which was composed of apaf-1 and cytochrome c in the cytoplasm and the response to cellular protein cleavage, and eventually resulted in occurrence of apoptosis [ 55 , 56 ]. However, the role of mitochondria in Drosophila apoptosis is not clear and evidence has proven that cytochrome c was not involved in caspases activation [ 57 , 58 ].…”