Molecular Cloning and Expression Analysis of Leucine Rich Repeat Containing G Protein Coupled Receptor 8 Gene (LGR8) in Half-smooth Tongue Sole (Cynoglossus semilaevis)
Abstract：Leucine rich repeat containing G protein coupled receptor 8 (LGR8) plays an important role in the process of testicular descent in male mammals. LGR8 gene in half smooth tongue sole (Cynoglossus semilaevis) was cloned on the basis of the entire genome and transcriptome sequencing using RACE method. LGR8 gene contained 2 768 nucleotides, and the open reading frame (ORF) was 2 205 bp, which encoded 734 amino acids, 272 bp of 5'-UTR and 296 bp of 5'-UTR. The amino acid sequences contained 10 LRRs areas, a LDL-A regional structure and a 7tm-1 domain. The results of Real-time fluorescent quantitative PCR (qRT-PCR) showed that LGR8 mainly expressed in brains and gonads of the sexual maturity male bodies of three years old fish, which was extremely higher than that of other tissues. There was no significant difference among the most tissues in females(except the intestine and the heart).. It was noteworthy that the expression level of LGR8 in the brain and gonad of males are significantly higher than that of females (P＜0.05). The results of gonad in different periods by qRT-PCR showed that LGR8 gene began to rise at 80 d, and the expression was up to the maximum amount between 150 and 210 d, when the expression was significantly higher than that in other tissues (P＜0.05). The results suggested that LGR8 might play a significant role in gender determination and development of the gonads in half smooth tongue sole which provides certain theoretical basis for the sex determination mechanism study of half smooth tongue sole.
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