title: Comparative study of two thioredoxins from common cutworm (Spodoptera litura): cloning, expression, and functional characterization.
abstract: Thioredoxins (Trxs) are a ubiquitous family of antioxidant enzymes that are involved in protecting organisms against various oxidative stresses. Here, we cloned and characterized two thioredoxins, named SlTrx1 and SlTrx2, from the common cutworm Spodoptera litura. SlTrx1 and SlTrx2, respectively, consist of 988 and 606 bp full-length cDNA with 318 and 447 bp open reading frames encoding 106 and 149 amino acid residues. Furthermore, the N-terminal region of SlTrx2 contains a predicted mitochondrial localization signal (33 amino acids). A phylogenetic relationship analysis revealed that SlTrx1 is in the cytosolic thioredoxin Trx1 cluster, whereas SlTrx2 is in the mitochondrial thioredoxin Trx2 cluster. Recombinant SlTrx1 (14 kDa) and SlTrx2 (16 kDa), expressed in baculovirus-infected insect Sf9 cells, demonstrated insulin disulfide reductase activity at the same optimum temperature and pH value of 35 °C and 7.0, respectively, in vitro. During S. litura development, we found that SlTrx1 and SlTrx2 had similar transcript expression patterns and were constitutively expressed in the epidermis, fat body, and midgut, with the highest expression occurring in the sixth-instar larval stage in the epidermis and midgut. In addition, both SlTrx1 and SlTrx2 mRNA were up-regulated in S. litura after injection with H2O2, cumene hydroperoxide, indoxacarb, and metaflumizone. These results suggest that SlTrx1 and SlTrx2 function as potent antioxidant enzymes, and provide a molecular basis for the roles SlTrx1 and SlTrx2 during development and the oxidative stress response of S. litura.
authors.affiliation: College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China.
authors.forename: Tinghao
authors.initials: T
authors.lastname: Kang
authors.affiliation: College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China.
authors.forename: Hu
authors.initials: H
authors.lastname: Wan
authors.affiliation: College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China.
authors.forename: Yashu
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Shakeel
authors.affiliation: College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China.
authors.forename: Yanhui
authors.initials: Y
authors.lastname: Lu
authors.affiliation: College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China.
authors.forename: Hong
authors.initials: H
authors.lastname: You
authors.affiliation: College of Natural Resources and Life Science, Dong-A University, Busan 604-714, Republic of Korea.
authors.forename: Kwang Sik
authors.initials: KS
authors.lastname: Lee
authors.affiliation: College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China; College of Natural Resources and Life Science, Dong-A University, Busan 604-714, Republic of Korea. Electronic address: brjin@dau.ac.kr.
authors.forename: Byung Rae
authors.initials: BR
authors.lastname: Jin
authors.affiliation: College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China. Electronic address: jianhl@mail.hzau.edu.cn.
authors.forename: Jianhong
authors.initials: J
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D007814:Larva / Q000378:metabolism; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D018411:Spodoptera / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D013879:Thioredoxins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D019476:Insect Proteins; D013879:Thioredoxins
keywords: Antioxidant enzyme; Common cutworm; Oxidative stress; Spodoptera litura; Thioredoxin