1
|
Zhang RN, Ren FF, Zhou CB, Xu JF, Yi HY, Ye MQ, Deng XJ, Cao Y, Yu XQ, Yang WY. An ML protein from the silkworm Bombyx mori may function as a key accessory protein for lipopolysaccharide signaling. Dev Comp Immunol 2018; 88:94-103. [PMID: 30009928 DOI: 10.1016/j.dci.2018.07.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 07/11/2018] [Accepted: 07/12/2018] [Indexed: 06/08/2023]
Abstract
Lipopolysaccharide (LPS) is a common component of the outermost cell wall in Gram-negative bacteria. In mammals, LPS serves as an endotoxin that can be recognized by a receptor complex of TLR4 (Toll-like receptor 4) and MD-2 (myeloid differentiation-2) and subsequently induce a strong immune response to signal the release of tumor necrosis factor (TNF). In Drosophila melanogaster, no receptors for LPS have been identified, and LPS cannot activate immune responses. Here, we report a protein, BmEsr16, which contains an ML (MD-2-related lipid-recognition) domain, may function as an LPS receptor in the silkworm Bombyx mori. We showed that antibacterial activity in the hemolymph of B. mori larvae was induced by Escherichia coli, peptidoglycan (PGN) and LPS and that the expression of antimicrobial peptide genes was also induced by LPS. Furthermore, both the expression of BmEsr16 mRNA in the fat body and the expression of BmEsr16 protein in the hemolymph were induced by LPS. Recombinant BmEsr16 bound to LPS and lipid A, as well as to PGN, lipoteichoic acid, but not to laminarin or mannan. More importantly, LPS-induced immune responses in the hemolymph of B. mori larvae were blocked when the endogenous BmEsr16 protein was neutralized by polyclonal antibody specific to BmEsr16. Our results suggest that BmEsr16 may function as a key accessory protein for LPS signaling in B. mori.
Collapse
Affiliation(s)
- Ruo-Nan Zhang
- Laboratory of Insect Molecular Biology and Biotechnology, Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Fei-Fei Ren
- Laboratory of Insect Molecular Biology and Biotechnology, Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Cheng-Bo Zhou
- Laboratory of Insect Molecular Biology and Biotechnology, Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Jun-Feng Xu
- Laboratory of Insect Molecular Biology and Biotechnology, Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Hui-Yu Yi
- Laboratory of Insect Molecular Biology and Biotechnology, Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Ming-Qiang Ye
- The Sericultural and Agri-Food Research Institute of the Guangdong Academy of Agricultural Sciences, Guangzhou 510642, China
| | - Xiao-Juan Deng
- Laboratory of Insect Molecular Biology and Biotechnology, Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Yang Cao
- Laboratory of Insect Molecular Biology and Biotechnology, Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Xiao-Qiang Yu
- Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology & School of Life Sciences, South China Normal University, Guangzhou 510631, China.
| | - Wan-Ying Yang
- Laboratory of Insect Molecular Biology and Biotechnology, Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
| |
Collapse
|
2
|
Liao C, Upadhyay A, Liang J, Han Q, Li J. 3,4-Dihydroxyphenylacetaldehyde synthase and cuticle formation in insects. Dev Comp Immunol 2018; 83:44-50. [PMID: 29155013 DOI: 10.1016/j.dci.2017.11.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 10/28/2017] [Accepted: 11/13/2017] [Indexed: 06/07/2023]
Abstract
Cuticle is the most important structure that protects mosquitoes and other insect species from adverse environmental conditions and infections of microorganism. The physiology and biochemistry of insect cuticle formation have been studied for many years and our understanding of cuticle formation and hardening has increased considerably. This is especially true for flexible cuticle. The recent discovery of a novel enzyme that catalyzes the production of 3,4-dihydroxyphenylacetaldehyde (DOPAL) in insects provides intriguing insights concerning the flexible cuticle formation in insects. For convenience, the enzyme that catalyzes the production DOPAL from l-dopa is named DOPAL synthase. In this mini-review, we summarize the biochemical pathways of cuticle formation and hardening in general and discuss DOPAL synthase-mediated protein crosslinking in insect flexible cuticle in particular.
Collapse
Affiliation(s)
- Chenghong Liao
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou, Hainan 570228, China; Laboratory of Tropical Veterinary Medicine and Vector Biology, Hainan Key Laboratory of Sustainable Utilization of Tropical Bioresources, Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, Hainan 570228, China
| | - Archana Upadhyay
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou, Hainan 570228, China; Laboratory of Tropical Veterinary Medicine and Vector Biology, Hainan Key Laboratory of Sustainable Utilization of Tropical Bioresources, Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, Hainan 570228, China
| | - Jing Liang
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
| | - Qian Han
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou, Hainan 570228, China; Laboratory of Tropical Veterinary Medicine and Vector Biology, Hainan Key Laboratory of Sustainable Utilization of Tropical Bioresources, Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, Hainan 570228, China.
| | - Jianyong Li
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA.
| |
Collapse
|
3
|
Abstract
The cuticular exoskeleton of insects and other arthropods is a remarkably versatile material with a complex multilayer structure. We made use of the ability to isolate cuticle synthesizing cells in relatively pure form by dissecting pupal wings and we used RNAseq to identify genes expressed during the formation of the adult wing cuticle. We observed dramatic changes in gene expression during cuticle deposition, and combined with transmission electron microscopy, we were able to identify candidate genes for the deposition of the different cuticular layers. Among genes of interest that dramatically change their expression during the cuticle deposition program are ones that encode cuticle proteins, ZP domain proteins, cuticle modifying proteins and transcription factors, as well as genes of unknown function. A striking finding is that mutations in a number of genes that are expressed almost exclusively during the deposition of the envelope (the thin outermost layer that is deposited first) result in gross defects in the procuticle (the thick chitinous layer that is deposited last). An attractive hypothesis to explain this is that the deposition of the different cuticle layers is not independent with the envelope instructing the formation of later layers. Alternatively, some of the genes expressed during the deposition of the envelope could form a platform that is essential for the deposition of all cuticle layers. Insects and other arthropods are an extremely successful group of animals. A unique and key feature of their lifestyle is their chitin containing cuticular exoskeleton, a complex layered material, which remains rather poorly understood for so prominent of a biological material. We have characterized the gene expression pattern of wing epithelial cells over the period of cuticle formation and also carried out transmission electron microscopy, which allows us to identify genes that likely play a role in the formation of different cuticle layers. Functional studies suggest that the deposition of the earliest layer influences the deposition of the later ones.
Collapse
Affiliation(s)
- Lukasz F. Sobala
- Biology Department and Cell Biology Department, University of Virginia, Charlottesville, Virginia, United States of America
| | - Paul N. Adler
- Biology Department and Cell Biology Department, University of Virginia, Charlottesville, Virginia, United States of America
- * E-mail:
| |
Collapse
|
4
|
Jonusaite S, Donini A, Kelly SP. Occluding junctions of invertebrate epithelia. J Comp Physiol B 2016; 186:17-43. [DOI: 10.1007/s00360-015-0937-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 09/12/2015] [Accepted: 09/22/2015] [Indexed: 01/30/2023]
|
5
|
Roer R, Abehsera S, Sagi A. Exoskeletons across the Pancrustacea: Comparative Morphology, Physiology, Biochemistry and Genetics. Integr Comp Biol 2015; 55:771-91. [DOI: 10.1093/icb/icv080] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
|
6
|
Shi XZ, Kang CJ, Wang SJ, Zhong X, Beerntsen BT, Yu XQ. Functions of Armigeres subalbatus C-type lectins in innate immunity. Insect Biochem Mol Biol 2014; 52:102-14. [PMID: 25014898 PMCID: PMC4143534 DOI: 10.1016/j.ibmb.2014.06.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 06/03/2014] [Accepted: 06/11/2014] [Indexed: 05/16/2023]
Abstract
C-type lectins (CTLs) are a superfamily of calcium-dependent carbohydrate binding proteins containing at least one carbohydrate-recognition domain (CRD) and they are present in almost all metazoans. Insect CTLs may function as pattern-recognition receptors and play important roles in innate immunity. In this study, we selected five AsCTLs from the mosquito Armigeres subalbatus, a natural vector of filarial nematodes, and performed both in vitro and in vivo studies to elucidate their functions in innate immunity. AsCTLMA15, AsCTLGA5 and AsCTL15 were mainly expressed in hemocytes, AsCTL16 was expressed in fat body, while AsCTLMA11 was expressed in both hemocytes and fat body, and only AsCTLMA11 and AsCTL16 were expressed at high levels in adult females. In vitro binding assays showed that all five recombinant AsCTLs could bind to different microbial cell wall components, including lipopolysaccharide (LPS), lipid A, peptidoglycan (PG), lipoteichoic acid (LTA), zymosan and laminarin (beta-1,3-glucan). Recombinant AsCTLs also bound to several Gram-negative and Gram-positive bacteria, and could agglutinate bacterial cells. Injection of double-stranded RNAs (dsRNAs) could significantly reduce expression of the five AsCTL mRNAs, and the survival of mosquitoes treated with dsRNA to AsCTLGA5 was significantly decreased after Escherichia coli infection, but did not change significantly after Micrococcus luteus infection compared to the control groups, suggesting that Ar. subalbatus AsCTLGA5 may participate in innate immunity against E. coli.
Collapse
Affiliation(s)
- Xiu-Zhen Shi
- School of Life Sciences, Shandong University, 27 Shanda South Road, Jinan 250100, China; Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO 64110, USA
| | - Cui-Jie Kang
- School of Life Sciences, Shandong University, 27 Shanda South Road, Jinan 250100, China; Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO 64110, USA
| | - Song-Jie Wang
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - Xue Zhong
- Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO 64110, USA
| | - Brenda T Beerntsen
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - Xiao-Qiang Yu
- Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO 64110, USA.
| |
Collapse
|
7
|
Shi XZ, Yu XQ. The extended loop of the C-terminal carbohydrate-recognition domain of Manduca sexta immulectin-2 is important for ligand binding and functions. Amino Acids 2011; 42:2383-91. [PMID: 21805136 DOI: 10.1007/s00726-011-0980-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Accepted: 07/07/2011] [Indexed: 11/24/2022]
Abstract
Our previous research showed that immulectin-2 (IML-2), a C-type lectin from the tobacco hornworn, Manduca sexta, is a pattern recognition receptor (PRR) that can bind to pathogen-associated molecular patterns (PAMPs), such as lipopolysaccharide (LPS), peptidoglycan (PG) and β-1,3-glucan, and IML-2 plays an important role in cellular encapsulation, melanization, phagocytosis, and prophenoloxidase (proPO) activation. Unlike most mammalian C-type lectins that contain a single carbohydrate-recognition domain (CRD), IML-2 is composed of tandem CRDs, and the C-terminal CRD2 contains an extended loop, which is not present in most C-type CRDs. We hypothesize that the extended loop may participate in ligand binding, encapsulation, melanization, phagocytosis and/or proPO activation in M. sexta. To test this hypothesis, two deletion mutant proteins (IML-2Δ220-244 and IML-2Δ220-257), in which the extended loop of the CRD2 was partially or completely deleted, were expressed and purified. By comparing the characteristics of recombinant IML-2, IML-2Δ220-244 and IML-2Δ220-257, we found that deletion of the extended loop in CRD2 impaired the ability of IML-2 to bind microbial PAMPs and to stimulate proPO activation, indicating that the extended loop of IML-2 plays an important role in ligand binding and biological functions.
Collapse
Affiliation(s)
- Xiu-Zhen Shi
- Division of Cell Biology and Biophysics, School of Biological Sciences, University of Missouri-Kansas City, 5007 Rockhill Road, Kansas City, MO 64110, USA
| | | |
Collapse
|
8
|
Rao XJ, Ling E, Yu XQ. The role of lysozyme in the prophenoloxidase activation system of Manduca sexta: an in vitro approach. Dev Comp Immunol 2010; 34:264-71. [PMID: 19835909 PMCID: PMC2813938 DOI: 10.1016/j.dci.2009.10.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2009] [Revised: 09/25/2009] [Accepted: 10/06/2009] [Indexed: 05/10/2023]
Abstract
Activation of the prophenoloxidase (proPO) system and synthesis of antimicrobial peptides (including lysozyme) are two key defense mechanisms in arthropods. Activation of proPO involves a cascade of serine proteinases that eventually converts proPO to active phenoloxidase (PO). However, a trade-off between lysozyme/antibacterial activity and PO activity has been observed in some insects, and a mosquito lysozyme can inhibit melanization. It is not clear whether lysozyme can inhibit PO activity and/or proPO activation. In this study, we used in vitro assays to investigate the role of lysozyme in proPO activation in the tobacco hornworm Manduca sexta. We showed that lysozymes from M. sexta, human milk and hen egg white did not inhibit PO activity in the pre-activated naïve plasma of M. sexta larvae, but significantly inhibited proPO activation in the naïve plasma. Western blot analysis showed that direct incubation of M. sexta lysozyme with the naïve plasma prevented conversion of proPO to PO, but stimulated degradation of precursor proteins for serine proteinase homolog-2 (SPH2) and proPO-activating proteinase-1 (PAP1), two key components required for proPO activation. Far-western blot analysis showed that M. sexta lysozyme and proPO interacted with each other. Altogether, our results suggest that lysozymes may inhibit the proPO activation system by preventing conversion of proPO to PO via direct protein interaction with proPO.
Collapse
Affiliation(s)
- Xiang-Jun Rao
- Division of Cell Biology and Biophysics, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO 64110, USA
| | - Erjun Ling
- Division of Cell Biology and Biophysics, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO 64110, USA
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Xiao-Qiang Yu
- Division of Cell Biology and Biophysics, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO 64110, USA
- Send correspondence to: Xiao-Qiang Yu, Division of Cell Biology and Biophysics, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO 64110, Telephone: (816)-235-6379, Fax: (816)-235-1503,
| |
Collapse
|
9
|
Ling E, Rao XJ, Ao JQ, Yu XQ. Purification and characterization of a small cationic protein from the tobacco hornworm Manduca sexta. Insect Biochem Mol Biol 2009; 39:263-71. [PMID: 19162182 PMCID: PMC2659724 DOI: 10.1016/j.ibmb.2008.12.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2008] [Revised: 12/18/2008] [Accepted: 12/22/2008] [Indexed: 05/10/2023]
Abstract
The prophenoloxidase (proPO) activation system is an important defense mechanism in arthropods, and activation of proPO to active phenoloxidase (PO) involves a serine proteinase cascade. Here, we report the purification and characterization of a small cationic protein CP8 from the tobacco hornworm, Manduca sexta, which can stimulate proPO activation. BLAST search showed that Manduca CP8 is similar to a fungal proteinase inhibitor-1 (AmFPI-1), an inducible serine proteinase inhibitor-1 (ISPI-1), and other small cationic proteins with unknown functions. However, we showed that Manduca CP8 did not inhibit proteinase activity, but stimulated proPO activation in plasma. When small amount (0.1 microg) of purified native CP8 or BSA was added to cell-free plasma samples and incubated for 20 min, low PO activity was observed in both groups. But significantly higher PO activity was observed in the CP8-group than in the BSA-group when more proteins (0.5 microg) were added and incubated for 20 min. However, when the plasma samples were incubated with proteins for 30 min, high PO activity was observed in both the CP8 and BSA groups regardless of the amount of proteins added. Moreover, when PO in the plasma was pre-activated with Micrococcus luteus, addition of CP8 did not have an effect on PO activity, and CP8/bacteria mixture did not stimulate PO activity to a higher level than did BSA/bacteria. These results suggest that CP8 helps activate proPO more rapidly at the initial stage. CP8 mRNA was specifically expressed in fat body and its mRNA level decreased when larvae were injected with saline or bacteria. However, CP8 protein concentration in hemolymph did not change significantly in larvae injected with saline or microorganisms.
Collapse
Affiliation(s)
| | | | | | - Xiao-Qiang Yu
- Send correspondence to: Xiao-Qiang Yu, Ph.D., Division of Cell Biology and Biophysics, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO 64110, Telephone: (816)-235-6379, Fax: (816)-235-1503,
| |
Collapse
|
10
|
Niu BL, Shen WF, Liu Y, Weng HB, He LH, Mu JJ, Wu ZL, Jiang P, Tao YZ, Meng ZQ. Cloning and RNAi-mediated functional characterization of MaLac2 of the pine sawyer, Monochamus alternatus. Insect Mol Biol 2008; 17:303-12. [PMID: 18477244 DOI: 10.1111/j.1365-2583.2008.00803.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Laccase, a member of a group of proteins collectively known as multicopper oxidases, is hypothesized to play an important role in insect cuticle sclerotization by oxidizing catechols in the cuticle to their corresponding quinones, which then catalyze protein cross-linking reactions. Laccase 2 has been proved as the gene required for beetle cuticle tanning through RNA interference (RNAi) experiments on red flour beetle Tribolium castaneum. The pine sawyer beetle, Monochamus alternatus (Coleoptero: Cerambycidae) is the insect serving as a major vector of the pinewood nematode, Bursaphelenchus xylophilus, which is the causative agent for pine wilt disease. The cDNA of MaLac2 was cloned from the insect in this study. The conceptual amino-acid sequence deduced was much conserved with other known insect laccases, particularly with the enzyme of Tribolium castaneum. Injection in hemolymph of pine sawyer larva of dsRNA targeting the laccase 2 mRNA leads to important alterations of the tanning, hardening and sclerotization of the pupal and adult cuticles. Defaults appear in a dose-dependent manner and high loads of dsRNA are lethal. The decrease of the endogenous laccase 2 mRNA affects the procuticle which is thinner and without the characteristic piling up of successive layers. The observations reinforce the role of laccase 2 as an essential phenoloxidase for making cuticle.
Collapse
Affiliation(s)
- B-L Niu
- Laboratory of Entomo-molecular Biology, Sericultural Research Institute, Zhejiang Academy of Agricultural Science, Hangzhou 310021, China
| | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Ao JQ, Ling E, Rao XJ, Yu XQ. A novel ML protein from Manduca sexta may function as a key accessory protein for lipopolysaccharide signaling. Mol Immunol 2008; 45:2772-81. [PMID: 18343500 DOI: 10.1016/j.molimm.2008.02.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2008] [Revised: 02/04/2008] [Accepted: 02/06/2008] [Indexed: 01/03/2023]
Abstract
Lipopolysaccharide (LPS) present on the outer membrane of Gram-negative bacteria is one of the most important pathogen-associated molecular patterns and a potent elicitor in innate immunity. In human, TLR4 (Toll-like receptor 4) and MD-2 (myeloid differiation-2) form a receptor complex to transduce the LPS signal into cells. However, in invertebrates, receptors that recognize LPS have not been determined. Here we report the purification, characterization and cDNA cloning of an ML (MD-2-related lipid-recognition) protein from the tobacco hornworm Manduca sexta. The full-length cDNA of this M. sexta ML protein, named MsML-1, is 532bp with an open reading frame of 456bp that encodes a polypeptide of 151 amino acids containing an ML domain. MsML-1 is a secreted glycoprotein and its mRNA is expressed in fat body and hemocytes. The expression level of MsML-1 mRNA in fat body and hemocytes as well as MsML-1 protein in hemolymph are not induced by immune challenge. Recombinant MsML-1 protein specifically binds to LPS from several Gram-negative bacteria and LPS Re mutant, as well as to lipid A, but not to KDO (2-keto-3-deoxyoctonate). Our results suggest that MsML-1 may function as a key accessory protein for LPS signaling in M. sexta against Gram-negative bacterial infection.
Collapse
Affiliation(s)
- Jing-qun Ao
- Division of Cell Biology and Biophysics, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO 64110, USA
| | | | | | | |
Collapse
|
12
|
Abstract
C-type lectins are calcium-dependent carbohydrate binding proteins, and animal C-type lectins participate in innate immunity and cell-cell interactions. In the fruit fly Drosophila melanogaster, more than 30 genes encode C-type lectin domains. However, functions of Drosophila C-type lectins in innate immunity are not well understood. This study is to investigate whether two Drosophila C-type lectins, CG33532 and CG33533 (designated as DL2 and DL3, respectively), are involved in innate immune responses. Recombinant DL2 and DL3 were expressed and purified. Both DL2 and DL3 agglutinated Gram-negative Escherichia coli in a calcium-dependent manner. Though DL2 and DL3 are predicted to be secreted proteins, they were detected on the surface of Drosophila hemocytes, and recombinant DL2 and DL3 also directly bound to hemocytes. Coating of agarose beads with recombinant DL2 and DL3 enhanced their encapsulation and melanization by Drosophila hemocytes in vitro. However, hemocyte encapsulation was blocked when the lectin-coated beads were pre-incubated with rat polyclonal antibody specific for DL2 or DL3. Our results suggest that DL2 and DL3 may act as pattern recognition receptors to mediate hemocyte encapsulation and melanization by directly recruiting hemocytes to the lectin-coated surface.
Collapse
Affiliation(s)
| | | | - Xiao-Qiang Yu
- Send correspondence to: Xiao-Qiang Yu, Division of Cell Biology and Biophysics, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO 64110, Telephone: (816)-235-6379, Fax: (816)-235-1503,
| |
Collapse
|
13
|
Abstract
Insect C-type lectins function as pattern recognition receptors in innate immunity. In the tobacco hornworm Manduca sexta, we have previously isolated three C-type lectins named immulectins, which are involved in innate immune responses. Here, we report a new member of the immulectin family, immulectin-4 (IML-4). IML-4 mRNA was detected in the fat body of control larvae and was induced in the fat body when larvae were injected with bacteria. Recombinant IML-4 bound to bacterial lipopolysaccharide (LPS) and lipoteichoic acid (LTA), and the binding activity was not affected by addition of calcium or EGTA. IML-4 agglutinated bacteria and yeast, and agglutination of Escherichia coli by IML-4 was concentration- and calcium-dependent. IML-4 also enhanced haemocyte encapsulation and melanization.
Collapse
Affiliation(s)
- X-Q Yu
- Division of Cell Biology and Biophysics, School of Biological Sciences, University of Missouri-Kansas City, 64110, USA.
| | | | | | | |
Collapse
|
14
|
Arakane Y, Muthukrishnan S, Beeman RW, Kanost MR, Kramer KJ. Laccase 2 is the phenoloxidase gene required for beetle cuticle tanning. Proc Natl Acad Sci U S A 2005; 102:11337-42. [PMID: 16076951 PMCID: PMC1183588 DOI: 10.1073/pnas.0504982102] [Citation(s) in RCA: 234] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2005] [Indexed: 11/18/2022] Open
Abstract
Cuticle tanning (or sclerotization and pigmentation) in invertebrates involves the oxidative conjugation of proteins, which renders them insoluble and hardens and darkens the color of the exoskeleton. Two kinds of phenoloxidases, laccase and tyrosinase, have been proposed to participate in tanning, but proof of the true identity of the enzyme(s) responsible for this process has been elusive. We report the cloning of cDNAs for laccases and tyrosinases from the red flour beetle, Tribolium castaneum, as well as their developmental patterns of expression. To test for the involvement of these types of enzymes in cuticle tanning, we performed RNA interference experiments to decrease the levels of individual phenoloxidases. Normal phenotypes were obtained after dsRNA-mediated transcript depletion for all phenoloxidases tested, with the exception of laccase 2. Insects injected with dsRNA for the laccase 2 gene failed to tan, were soft-bodied and deformed, and subsequently died in a dsRNA dose-dependent fashion. The results presented here support the hypothesis that two isoforms of laccase 2 generated by alternative splicing catalyze larval, pupal, and adult cuticle tanning in Tribolium.
Collapse
Affiliation(s)
- Yasuyuki Arakane
- Grain Marketing and Production Research Center, Agricultural Research Service, United States Department of Agriculture, 1515 College Avenue, Manhattan, KS 66502, USA.
| | | | | | | | | |
Collapse
|
15
|
Yu XQ, Tracy ME, Ling E, Scholz FR, Trenczek T. A novel C-type immulectin-3 from Manduca sexta is translocated from hemolymph into the cytoplasm of hemocytes. Insect Biochem Mol Biol 2005; 35:285-295. [PMID: 15763465 DOI: 10.1016/j.ibmb.2005.01.004] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2004] [Revised: 12/17/2004] [Accepted: 01/03/2005] [Indexed: 05/24/2023]
Abstract
Lectins interact with carbohydrates. They can function as pattern recognition receptors and play an important role in the innate immune system of animals. Previously, we have isolated two calcium-dependent (C-type) lectins, named immulectin-1 and -2, from the tobacco hornworm Manduca sexta. Both immulectin-1 and -2 stimulate prophenoloxidase activation in plasma. Here, we describe isolation and cDNA cloning of a novel member of immulectins, immulectin-3 (IML-3). IML-3, like immulectin-1 and -2, contains tandem carbohydrate-recognition domains (CRDs). The cDNA clone encoding IML-3 is 3802 bp long, with an open reading frame of 930 bp. This cDNA clone has an extremely long noncoding region at the 3' end that contains eight polyadenylation signal sequences. Northern analysis showed that a 5.0 kb IML-3 transcript was present in the fat body of control larvae (injected with saline) but not in the fat body of larvae injected with bacteria. However, a much more abundant 3.1 kb transcript was induced in the fat body of bacteria-injected larvae. IML-3 mRNA was not detected in hemocytes of control or bacteria-injected larvae. Recombinant IML-3 was expressed in bacteria and purified. It specifically bound to immobilized lipopolysaccharide (LPS) and lipoteichoic acid from bacteria, and to laminarin, a beta-1, 3-glucan. Binding of IML-3 to immobilized LPS was competed by excess free LPS. More importantly, IML-3 contains an anti-death-like motif in the carboxyl-terminal CRD. Endogenous IML-3 was detected in the cytoplasm of hemocytes, and FITC-labeled recombinant IML-3 was translocated from hemolymph into hemocytes. Coating of IML-3 onto agarose beads enhanced encapsulation of the beads.
Collapse
Affiliation(s)
- Xiao-Qiang Yu
- Division of Cell Biology and Biophysics, School of Biological Sciences, University of Missouri-Kansas City, 5007 Rockhill Road, Kansas City, MO 64110, USA.
| | | | | | | | | |
Collapse
|
16
|
Dittmer NT, Suderman RJ, Jiang H, Zhu YC, Gorman MJ, Kramer KJ, Kanost MR. Characterization of cDNAs encoding putative laccase-like multicopper oxidases and developmental expression in the tobacco hornworm, Manduca sexta, and the malaria mosquito, Anopheles gambiae. Insect Biochem Mol Biol 2004; 34:29-41. [PMID: 14723895 DOI: 10.1016/j.ibmb.2003.08.003] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Laccase (EC 1.10.3.2) is an enzyme with p-diphenol oxidase activity that is a member of a group of proteins collectively known as multicopper, or blue copper, oxidases. Laccase is hypothesized to play an important role in insect cuticle sclerotization by oxidizing catechols in the cuticle to their corresponding quinones, which then catalyze protein cross-linking reactions. To facilitate studies of the structure, function and regulation of insect laccases, we have cloned two cDNAs for laccases from the tobacco hornworm, Manduca sexta (MsLac1 and 2), and one from the malaria mosquito, Anopheles gambiae (AgLac1). The MsLac1 and 2 cDNAs encode proteins of 801 amino acids (aa) and 760 aa, respectively, while the AgLac1 cDNA encodes a protein of 1009 aa. All three cDNAs contain putative secretion signal sequences, and the 10 histidines and one cysteine that form the copper-binding centers, as well as a methionine in the T1 copper center. Novel to the insect laccases, relative to both fungal and plant laccases, is a longer amino-terminal sequence characterized by a unique domain consisting of several conserved cysteine, aromatic, and charged residues. Northern blot analyses identified single transcripts of approximately 3.6, 3.5, and 4.4 kb for MsLac1, MsLac2, and AgLac1, respectively, and also showed that AgLac1 was expressed in all life stages of the mosquito. RT-PCR revealed that the MsLac1 transcript was most abundant in the midgut, Malpighian tubules, and epidermis, whereas the MsLac2 transcript was most abundant in the epidermis. MsLac2 showed strong expression in the pharate pupal and reduced expression in the early pupal epidermis, consistent with the laccases' presumed role in cuticle sclerotization.
Collapse
Affiliation(s)
- Neal T Dittmer
- Department of Biochemistry, 104 Willard Hall, Kansas State University, Manhattan, KS 66506, USA
| | | | | | | | | | | | | |
Collapse
|