Identification of an amphioxus intelectin homolog that preferably agglutinates gram-positive over gram-negative bacteria likely due to different binding capacity to LPS and PGN

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• 作者：Jie Yan^a ; Jianfeng Wang^a ; Yaqi Zhao^a ; Jingye Zhang^a ; Changcun Bai^a ; Changqing Zhang^a ; Chao Zhang^a ; Kailin Li^a ; Haiqing Zhang^b ; ^{zhanghq_sdpt@163.com} ; Xiumin Du^c ; ^{emily-du@163.com} ; Lijun Feng^a ; ^{drfeng@sdu.edu.cn}
• 关键词：Amphioxus ; Intelectin ; LPS ; PGN ; Bacterial agglutination
• 刊名：Fish & Shellfish Immunology
• 出版年：2012
• 出版时间：July, 2012
• 年：2012
• 卷：33
• 期：1
• 页码：11-20
• 全文大小：1517 K

文摘

Intelectin is a recently described galactofuranose-binding lectin that plays a role in innate immunity in vertebrates. Little is known about intelectin in invertebrates, including amphioxus, the transitional form between vertebrates and invertebrates.

We cloned an amphioxus intelectin homolog, AmphiITLN-like, coding 302 amino acids with a conserved fibrinogen-related domain (FReD) in the N-terminus and an Intelectin domain in the C-terminus. In situ hybridization in adult amphioxus showed that AmphiITLN-like transcripts were highly expressed in the digestive tract and the skin. Quantitative real-time PCR revealed that AmphiITLN-like is significantly up-regulated in response to Staphylococcus aureus challenge, but only modestly to Escherichia coli. In addition, recombinant AmphiITLN-like expressed in E.?coli agglutinates Gram-negative and Gram-positive bacteria to different degrees in a calcium dependent manner. Recombinant AmphiITLN-like could bind lipopolysaccharide (LPS) and peptidoglycan (PGN), the major cell wall components of Gram-negative and Gram-positive bacteria, respectively, with a higher affinity to PGN.

Our work identified and characterized for the first time an amphioxus intelectin homolog, and provided insight into the evolution and function of the intelectin family.