Presence and Characterization of Complement-like Activity in the Amphioxus Branchiostoma belcheri tsingtauense

Zhang, Shicui; Wang, Changfa; Wang, Yongjun; Wei, Ran; Jiang, Guohu; Ju, Hong

doi:10.2108/zsj.20.1207

Cited by 47 publications

(43 citation statements)

References 37 publications

(35 reference statements)

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“…To date, there is little functional information for the complement system of amphioxus, except for a few reports on the presence of C3, C6 (22), mannose-binding lectin-associated serine protease 1/3 (23), Bf/C2 (24), and complement-like activity in the humoral fluid (25). From the phylogenomic perspective, amphioxus appeared to have a sophisticated complement system full of amphioxus-specific novelties (10).…”

Section: Discussionmentioning

confidence: 99%

A Novel C1q Family Member of Amphioxus Was Revealed to Have a Partial Function of Vertebrate C1q Molecule

Huang

Wang

et al. 2008

The Journal of Immunology

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C1q is the target recognition protein of the classical complement pathway and a major connecting link between innate and adaptive immunities. Its globular signature domain is also found in a variety of noncomplement protein that can be grouped together as a C1q family. In this study, we have cloned and identified a novel C1q family member in cephalochordate amphioxus and named it as AmphiC1q1. The high transcriptional levels of this gene were detected during all stages of embryonic development, and the section in situ hybridization demonstrated that AmphiC1q1 was mainly expressed in the ovary, intestine, and nerve system of mature individuals. The transcript of AmphiC1q1 was up-regulated by LPS and Gram-negative bacteria, but hardly by lipoteichoic acid and Staphylococcus aureus. The recombinant AmphiC1q1 protein could not bind with N-acetyl-glucosamine and did not possess hemagglutinating activity, indicating that AmphiC1q1 could not act as its lamprey homologue. But both the full-length protein and its truncated globular domain of C1q protein could interact with LPS. Moreover, recombinant AmphiC1q1 protein could inhibit collagen-induced platelet aggregation, but the truncated globular C1q domain protein would not, indicating that the blocking activity of AmphiC1q1 protein was via the collagen region of the protein. Our study on the primitive form of C1q family in protochordate will shed a light on understanding the gradual functional evolution of C1q family and eventual formation of mammalian homologues.

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Section: Discussionmentioning

confidence: 99%

A Novel C1q Family Member of Amphioxus Was Revealed to Have a Partial Function of Vertebrate C1q Molecule

Huang

Wang

et al. 2008

The Journal of Immunology

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“…It has a heart (Holland et al 2003) and a circulation system with the fundamental organization of all chordates (Rähr 1979). Our previous investigation has shown that humoral fluids, including the blood, in amphioxus contain phenoloxidase, lectin and complement component C3 (Pang et al 2004(Pang et al , 2005Wang et al 2002;Zhang et al 2003), but little is known regarding the plasma proteins, including AT, in amphioxus to date.…”

Section: Introductionmentioning

confidence: 99%

Presence and localization of antithrombin and its regulation after acute lipopolysaccharide exposure in amphioxus, with implications for the origin of vertebrate liver

et al. 2005

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Antithrombin (AT), which is mainly synthesized in the liver, is an acute-phase plasma protein in mammalian species. Here, we demonstrated that sheep anti-human AT antibody cross-reacted with the humoral fluids in amphioxus Branchiostoma belcheri tsingtauense as well as human serum. The concentration of AT in the humoral fluids in amphioxus decreased slightly at first and then increased after the acute challenge with lipopolysaccharide, while the level of total proteins remained unchanged. These suggest the presence of the same acute-phase response pattern in amphioxus, as observed in some mammalian species. Immunohistochemically, AT was localized in the hepatic diverticulum. It is clear that the hepatic diverticulum in amphioxus is homologous to the vertebrate liver with respect to AT synthesis. This lends support to the hypothesis originally suggested by Müller that the vertebrate liver evolved from the hepatic diverticulum of an amphioxus-like ancestor during early chordate evolution.

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“…As comparison, BjFCN1 protein (15 g) and humoral fluid (30 g) alone were used as a positive control, respectively. Amphioxus humoral fluid was prepared by the method previously described (39).…”

Section: Methodsmentioning

confidence: 99%

“…Bacterial Binding Activity of Humoral BjC3-It is reported that amphioxus humoral fluid contains high concentration of C3 and mediates hemolytic activity for mammalian erythrocytes (39). To provide more supporting evidence for a functional humoral complement pathway, amphioxus humoral fluid was incubated with several types of bacteria and the binding activity of humoral BjC3 to bacteria was analyzed using Western blotting under reducing conditions.…”

Section: Identification Of Putative Ficolin Pathway Components Frommentioning

confidence: 99%

Functional Characterization of a Ficolin-mediated Complement Pathway in Amphioxus

Huang

et al. 2011

Journal of Biological Chemistry

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The ficolin-mediated complement pathway plays an important role in vertebrate immunity, but it is not clear whether this pathway exists in invertebrates. Here we identified homologs of ficolin pathway components from the cephalochordate amphioxus and investigated whether they had been co-opted into a functional ficolin pathway. Four of these homologs, ficolin FCN1, serine protease MASP1 and MASP3, and complement component C3, were highly expressed in mucosal tissues and gonads, and were significantly up-regulated following bacterial infection. Recombinant FCN1 could induce hemagglutination, discriminate among sugar components, and specifically recognize and aggregate several bacteria (especially Gram-positive strains) without showing bactericidal activity. This suggested that FCN1 is a dedicated pattern-recognition receptor. Recombinant serine protease MASP1/3 formed complexes with recombinant FCN1 and facilitated the activation of native C3 protein in amphioxus humoral fluid, in which C3 acted as an immune effector. We conclude that amphioxus have developed a functional ficolin-complement pathway. Because ficolin pathway components have not been reported in non-chordate species, our findings supported the idea that this pathway may represent a chordate-specific innovation in the evolution of the complement system.

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Presence and Characterization of Complement-like Activity in the Amphioxus Branchiostoma belcheri tsingtauense

Cited by 47 publications

References 37 publications

A Novel C1q Family Member of Amphioxus Was Revealed to Have a Partial Function of Vertebrate C1q Molecule

A Novel C1q Family Member of Amphioxus Was Revealed to Have a Partial Function of Vertebrate C1q Molecule

Presence and localization of antithrombin and its regulation after acute lipopolysaccharide exposure in amphioxus, with implications for the origin of vertebrate liver

Functional Characterization of a Ficolin-mediated Complement Pathway in Amphioxus

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