Identification and expression analysis of the MSP130-related-2 gene from Hyriopsis cumingii

MSP130-related-2 is thought to play a role in bio-mineralization as revealed in Crassostrea gigas and sea urchins. In this study, an MSP130-related-2 gene was isolated from Hyriopsis cumingii (HcMSP130-related-2) and characterized for the first time. The HcMSP130-related-2 cDNA was 2307 bp in length and consisted of a 572-bp 5'-untranslated region (5'-UTR), a 1239-bp open reading frame encoding 430-amino acid residues, and a 439-bp 3'-UTR. The molecular weight of the peptide was predicted to be 48551.3 Da, with a theoretical isoelectric point of 4.78 and instability index of 32.74, indicating that the protein is stable. The HcMSP130-related-2 amino acid residues included a signal peptide and several potential N-glycosylation sites. NCBI BLAST analysis indicated that this full-length amino acid sequence showed the highest similarity with HcMSP130-related-2 from C. gigas (45%) and about 38% identity with that from SpMSP130-rel-2 and Strongylocentrotus purpuratus. A phylogenetic tree showed that HcMSP130-rel-2 clustered with MSP130 from C. gigas. HcMSP130-related-2 was expressed in various tissues, including the mantle, blood, gill, foot, liver, kidney, intestine, and muscle, with the highest transcripts found in the mantle. Quantitative real-time polymerase chain reaction was used to analyze the expression of the HcMSP130- related-2 gene in grass carp after inducing shell damage. HcMSP130- related-2 expression was upregulated significantly in the mantle within 7 days (P < 0.05) after damage; however, the expression remained unchanged in the adductor muscle tissues (P > 0.05). These data suggest that HcMSP130-related-2 might be involved in shell formation in H. cumingii.