An LRR-only protein representing a new type of pattern recognition receptor in XXXX .

@entity14018 @entity1522 @entity368 @entity19852 @entity3689
UNASSIGNED: Accumulating evidence has demonstrated that @entity368 -rich repeat (LRR)-only proteins could mediate protein-ligand and protein-protein interactions and were involved in the immune response. In the present study, an LRR-only protein (designed as CfLRRop-1) was cloned from Zhikong scallop @entity19852 . The complete cDNA sequence of CfLRRop-1 contained an open reading frame (ORF) of 1377  bp, which encoded a protein of 458 @entity1522 . An LRRNT motif, an LRR_7 motif and seven LRR motifs were found in the deduced @entity3689 sequence of CfLRRop-1. And these seven LRR motifs contained a conserved signature sequence LxxLxLxxNxL. The mRNA transcripts of CfLRRop-1 were constitutively expressed in all the tested tissues, including haemocytes, muscle, mantle, gill, hepatopancreas and gonad, with the highest expression level in hepatopancreas. After the stimulation of lipopolysaccharide (LPS), peptidoglycan (PGN), glucan (GLU) and @entity14018 ( @entity14018 ), the mRNA transcripts of CfLRRop-1 in haemocytes all increased firstly within the first 6  h and secondly during 12-24  h post stimulation. The mRNA expression level of CfLRRop-1 was continuously up-regulated, after the expression of CfTLR (previously identified Toll-like receptor in @entity19852 ) was suppressed via RNA interference (RNAi). The recombinant CfLRRop-1 protein could directly bind LPS, PGN, GLU and @entity14018 , and induce the release of TNF-a in mixed primary cultured scallop haemocytes. These results collectively indicated that CfLRRop-1 would function as a powerful pattern recognition receptor (PRR) and play a pivotal role in the immune response of scallops.
