Cloning and tissue expression characteristics analysis of GPIHBP1 gene in Sewa sheep

【Objective】The glycosylated phosphatidylinositol anchored HDL-binding protein 1 gene (GPIHBP1) in the mammary gland tissue of Sewa sheep was cloned to clarify its bioinformatics characteristics and tissue expression dis-tribution characteristics,which provided a reference for revealing the mechanism of GPIHBP1 genes affecting milk pro-duction traits in sheep.【Method】The sequence of coding region (CDS) of GPIHBP1 gene of Sewa sheep was cloned,and bioinformatics analysis was carried out by online softwares such as Prot Para,Prot Scale,SOPMA,SWISS-MODEL,and TMHMM-2.0,and real-time fluorescence quantitative PCR was used to detect the expression of this gene in mam-mary gland,muscle,heart,kidney,liver,small intestine,rumen and ovary in sewa sheep.【Result】The CDS sequence of Sewa sheep GPIHBP1 gene was 519 bp long,encoding a total of 172 amino acid residues,and compared with the amino acid sequence of goat GPIHBP1 (XM_018058666.1),there were four amino acid changes(³²A→P,⁵²V→A,¹³⁰S→N and ¹⁷⁰M→V);the molecular weight of Sewa sheep GPIHBP1 protein was 18063.87 Da,and the theoretical isoelectric point (p I) was 4.29.There was no transmembrane helical structure,but there was a signal peptide (located at amino acids20-21),which was an extracellular acidic hydrophilic protein.There were 12 phosphorylation sites (6 serine phosphoryla-tion sites,5 threonine phosphorylation sites,1 tyrosine phosphorylation site) existed in the Sewa sheep GPIHBP1 pro-tein,and its secondary structure was in the state of irregularly curls (55.07%),followed by α-helix (35.47%),and the extended strand and β-turns accounted for 5.81%and 4.65%,respectively.GPIHBP1 gene was expressed in eight tissues including mammary gland,muscle,heart,kidney,liver,small intestine,rumen and ovary of Sewa sheep,and the highest relative expression was found in the mammary gland,followed by the heart and liver,which were both extremely signifi-cant higher than that in the muscle (P<0.01).【Conclusion】GPIHBP1 gene is expressed in different tissues of Sewa sheep,and the relative expression in mammary gland is the highest,which might be related to the increase or decrease in the expression of milk fat-related genes,among which,GPIHBP1 gene acts together with LPL gene and participate in the regulation of lactation in sheep