| Yi-Chen Liu a,b, Fu-Hua Li a, Bo Donga, Bing Wang a,
Wei Luana,b, Xiao-Jun Zhang a, Liu-Suo Zhang a,b, Jian-Hai Xiang a,∗
a Institute of Oceanology, Chinese Academy of Sciences, Key Laboratory of Experimental Marine Biology,
No. 7, Qingdao, Shandong 266071, China
b Graduate School, Chinese Academy of Sciences, Beijing 100039, China
Received 12 October 2005; received in revised form 4 January 2006; accepted 29 January 2006
Abstract
Lectin is regarded as a potential molecule involved in immune recognition and phagocytosis through opsonization in crustacean. Knowledge on lectin at molecular level would help us to understand its regulation mechanism in crustacean immune system. A novel C-type lectin gene (Fclectin)was cloned from hemocytes of Chinese shrimp Fenneropenaeus chinensis by 3_ and 5_ rapid amplification of cDNA ends (RACE) PCR. Thefull-length cDNA consists of 1482 bp with an 861 bp open reading frame, encoding 287 amino acids. The deduced amino acid sequence containsa putative signal peptide of 19 amino acids. It also contains two carbohydrate recognition domains/C-type lectin-like domains (CRD1 and CRD2),which share 78% identity with each other. CRD1 and CRD2 showed 34% and 30% identity with that of mannose-binding lectin from Japaneselamprey (Lethenteron japonicum), respectively. Both CRD1 and CRD2 of Fclectin have 11 amino acids residues, which are relatively invariantin animals’ C-type lectin CRDs. Five residues at Ca2+ binding site 1 are conserved in Fclectin. The potential Ca2+/carbohydrate-binding (site 2)motif QPD, E, NP (Gln-Pro-Asp, Glu, Asn-Pro) presented in the two CRDs of Fclectin may support its ability to bind galactose-type sugars.It could be deduced that Fclectin is a member of C-type lectin superfamily. Transcripts of Fclectin were found only in hemocytes by Northernblotting and RNA in situ hybridization. The variation of mRNA transcription level in hemocytes during artificial infection with bacteria and whitespot syndrome virus (WSSV) was quantitated by capillary electrophoresis after RT-PCR. An exploration of mRNA expression variation after LPSstimulation was carried out in primarily cultured hemocytes in vitro. Expression profiles of Fclectin gene were greatly modified after bacteria, LPSor WSSV challenge. The above-stated data can provide us clues to understand the probable role of C-type lectin in innate immunity of shrimp andwould be helpful to shrimp disease control.
© 2006 Elsevier Ltd. All rights
reserved.Keywords: C-type lectin; Cloning; Expression profile; Primary cell culture; Fenneropenaeus chinensis |
