Invasive Species Compendium

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Abstract Full Text

Cloning and expression analysis of caspase-3 in Spodoptera frugiperda.

Abstract

Cysteine proteases caspases are important enzymes in the process of apoptosis and participate in various insect physiological processes such as regulating the metamorphosis and responding to external pressure. In this study, the full length of the coding region of SpodOplera frugiperda Sf-Caspase-3 gene was identified and verified by transeriptome data and reverse transcription PCR, respectively. The gene coding region was 840 bp long and encoded 279 amino acids, with a predicted protein molecular weight of 31.43 kDa. Amino acid sequence analysis showed that Sf-easpase-3 had a conserved QACRC pentapeptide sequence and was highly conserved with Lep-easpase-3. Phylogenetic tree analysis showed that Sf-easpase- 3 had the Closest relationship with Spodoptera exigua Se-easpase-3. RT-qPCR results showed that Sf- Caspase-3 was expressed at every developmental stage of S. frugiperda, among which the 3rd ~ 6''1 instar larval stages owned the highest epression, and pupal and egg stages showed with the lowest expression. For different tissues of 6th instar larvae, the expression level of Sf-caspase-3 was the highest in the midgut, but was extremely low in the cuticle, fat body, and malpighian tubules. Besides, Sf-Caspase-3 prokaryotic expression recombinant plasmid was successfully constructed. A band of about 50 kDa was identified by SDS-PAGE 0f the recombinant strain sample which induced by 0.4 mmol/L isopropylthiogalactoside (IPTG) at 28 0C for 4 h. Protein solubility analysis showed that Sf-Caspase-3 mainly existed as insoluble form in inclusion bodies. This study provides a theoretical basis for further analysis of Sf-Caspase-3 function and the mechanism of lepidopteran insect apoptosis.