Cloning and functional analysis of ATG13 gene of Litopenaeus vannamei

【Objective】This study aimed to clone the autophagy-related gene 13（ATG13） from Litopenaeus vannamei, and investigate its tissue expression pattern and response to exogenous stimulation. These findings provided a theoretical basis for exploring the role of ATG13 gene in the process of disease-resistant infection of L.vannamei. 【Method】The ATG13 gene of L. vannamei was amplified by PCR, and bioinformatics analysis was performed by ProtParam, Softberry, SMART and InterProScan online softwares. Real-time fluorescence quantitative PCR was employed to determine the tissue expression of ATG13 gene in L. vannamei and its expression changes after stimulation by Vibrio harveyi and Poly（I:C）. 【Result】The open reading frame（ORF） of ATG13 gene was 1431 bp, encoding 476 amino acid residues. With a relative molecular weight of 52.4 kD and a theoretical isoelectric pI of 5.40, the ATG13 protein was a hydrophobic protein lacking signal peptide but containing an ATG13 functional domain（94-167 amino acids） at its N-terminus. The ATG13amino acid sequence of L. vannamei shared a high similarity（97%） with that of Drosophila melanogaster, and the phylogenetic tree based on ATG13 amino acid sequence similarity also indicated the closest relationship between L. vannamei and D. melanogaster. ATG13 gene was expressed in various tissues of L. vannamei, including hepatopancreas, muscles, gills, midgut, blood cells, heart, brain and skin. The relative expression of ATG13 gene was the highest in hepatopancreas, followed by muscle and midgut, and relatively low in skin and blood cells. After stimulation with V. harveyi and Poly（I:C）, the relative expression of ATG13 gene in hepatopancreas, midgut and gill tissues of L. vannamei initially increased and then decreased, and reached the highest value at 12, 24 or 48 h after stimulation, which was extremely significantly higher than control group（PBS）（P＜0.01）. 【Conclusion】After exogenous stimulation with V. harveyi or Poly（I:C）, L. vannamei up-regulates the expression of autophagy-related gene ATG13 to regulate the clearance of damaged organelles and maintain cell homeostasis, suggesting that ATG13 gene is involved in the response process of diseaseresistant infection of L. vannamei.