Objectives: To identify the alternative splicing isoform of mouse sweet taste receptor T1R2, and investigate the effect of lipopolysaccharide (LPS) local injection on T1R2 alternative splicing and the function of sweet taste receptor as one of the bacterial virulence factors.
Methods: After mouse taste bud tissue isolation was conducted, RNA extraction and reverse transcription polymerase chain reaction (PCR) were performed to identify the splicing isoform of T1R2. Heterologous expression experiments in vitro were utilized to detect how the T1R2 isoform regulated the function of sweet taste receptors. The effect of local LPS injection on the expression of the T1R2 isoform was measured by real-time fluorescent quantitative PCR.
Results: T1R2 splicing isoform T1R2_Δe3p formed sweet taste receptors with T1R3, which could not be activated by sweet taste stimuli and significantly downregulated the function of canonical T1R2/T1R3. Local LPS injection significantly increased the expression ratio of T1R2_Δe3p in mouse taste buds.
Conclusions: LPS stimulation affects the alternative splicing of mouse sweet taste receptor T1R2 and significantly upregulates the expression of non-functional isoform T1R2_Δe3p, suggesting that T1R2 alternative splicing regulation may be one of the mechanisms by which microbial infection affects host taste perception.
目的: 寻找小鼠甜味受体T1R2的剪接异构体，探究细菌毒力因子脂多糖（LPS）对T1R2可变剪接及甜味受体功能的影响。方法: 分离提取小鼠味蕾组织RNA，逆转录聚合酶链式反应（RT-PCR）寻找小鼠甜味受体T1R2剪接异构体，通过体外异源性表达实验检测T1R2异构体对甜味受体功能的影响，通过实时荧光定量聚合酶链式反应检测LPS局部注射对T1R2异构体表达的影响。结果: 小鼠甜味受体T1R2存在剪接异构体T1R2_Δe3p，其与T1R3组成的甜味受体无法被甜味刺激物激活，且可显著下调本构体T1R2/T1R3的功能；LPS局部注射可使小鼠味蕾内T1R2_Δe3p表达比例明显上升。结论: LPS刺激可影响小鼠甜味受体T1R2的可变剪接过程，显著上调无功能异构体T1R2_Δe3p的表达，提示T1R2可变剪接调控可能为微生物感染影响宿主味觉感知的机制之一。.
Keywords: alternative splicing; lipopolysaccharide; sweet taste receptor; taste perception.