关键词: 瘦素受体叠加转录蛋白样1, 尘螨, 粉尘螨, 基因克隆

Abstract: Objective　To obtain the leptin receptor overlapping transcript?like 1 encoding gene (LepROTL1 gene) from Dermatophagoides farina, investigate the molecular characteristics of the gene and construct a prokaryotic expression vector to express this gene. Methods　The LepROTL1 gene?encoding sequence fragments were captured based on the transcriptome sequencing results, and the full?length gene fragments were amplified from total RNA of D. farinae using a RT?PCR assay, and used to construct the expression plasmid pET28a(+)?LepROTL1, followed by sequencing. The plasmid was transformed into E. coli BL21 (DE3) T1R for the induction of IPTG expression. The expression product was characterized by SDS?PAGE and Western blotting. Bioinformatics analyses were performed to analyze the sequence and the molecular characteristics of its encoded protein. Results　The amplification products of the RT?PCR assay showed a clear band on agarose gel electrophoresis, and sequencing analysis of the pET28a(+)?LepROTL1 plasmid showed 417 bp in length of the coding gene from the start codon ATG to the termination codon TAA. Following the plasmid transformation into E. coli and induction with IPTG, a specific band was seen on SDS?PAGE, indicating successful expression. Bioinformatics analysis showed that the LepROTL1 gene?encoded protein was composed of 134 amino acids, and had a relative molecular weight of 14 378.13 Da, a hydrophilicity index of 1.149, and certain hydrophobicity. The secondary structure was composed of alpha?helix (19 aa, 14.18%), extended strand (48 aa, 35.82%) and random coil (67 aa, 50.00%). The deduced amino acid sequence was used to obtain homologous genes by BLAST, and the phylogenetic tree showed that D. farinae was clustered with D. pteronyssinus. Conclusion　The full?length sequences and expression plasmid of the LepROTL1 gene are obtained, and the molecular features of the gene are demonstrated using bioinformatics analyses, which provide insights into further studies on the gene.

Key words: Leptin receptor overlapping transcript?like 1, Dust mites, Dermatophagoides farinae, Gene cloning