Analysis of chicken SLC gene superfamily and its expression characteristics in different stages of eggshell formation

【Objective】 Identified members of the solute carrier(SLC) gene superfamily that might be involved in calcium transport during eggshell formation,and analyzed the expression characteristics of SLC genes at different stages of eggshell formation to lay the foundation for further investigating the correlation between SLC genes and eggshell formation and reveal the regulatory mechanism of calcium transport.【Method】 Based on the NCBI and Ensembl databases,the entire gene information of the chicken SLC gene superfamily was retrieved and organized,and bioinformatics analysis was performed through online software such as ProtParam,Pfam,TBtool,NPS@:SOPMA,Euk-mPLoc 2.0 and MEGA 11.0;moreover,real-time fluorescence quantitative PCR was used to analyze the expression characteristics of calcium transport-related SLC genes at different stages of eggshell formation.【Result】 The SLC gene superfamily in chickens included 56 subfamilies,which were distributed on 32 chromosomes including the Z chromosome. The encoded proteins were mainly distributed in the endoplasmic reticulum and cell membrane,and most of them were hydrophobic and alkaline proteins. They encompassed 81 structural domains and were mainly involved in the transportation of substances such as nucleotides,sugars,amino acids,neurotransmitters,inorganic ions,and organic ions. Among them,the SLC gene subfamilies related to calcium ions(Ca²⁺) included SLC4,SLC8,SLC9,SLC24 and SLC30. The SLC8 and SLC24 subfamily genes had a close evolutionary relationship and possessed structural domains directly related to Ca²⁺ transport. They were mainly located on the cell membrane and endoplasmic reticulum. Real-time fluorescence quantitative PCR detection results showed that the expression of SLC8 and SLC24 genes,which regulated Ca²⁺,in the uterus of laying hens was significantly higher than that in non-laying hens(P<0.05,the same below),further indicating that both were indeed involved in the regulation of Ca²⁺ transmembrane transport,but with different functions among members.【Conclusion】 The coding products of the chicken SLC gene superfamily are mostly hydrophobic alkaline proteins,which contain structural domains that bind to various substances. They are localized on the cell or various subcellular membrane structures,indicating that SLC family protein members are involved in the transmembrane transport of various substances. Among them, SLC8 and SLC24 subfamily genes cooperatively regulate the release of Ca²⁺ from the endoplasmic reticulum during the formation of eggshells and complete the transmembrane transport,secretion to the uterine part of the oviduct,and participate in the formation of the eggshell.