PMCA1-4及其A端和C端剪接变异体在成年大鼠前庭组织中的表达

The Expression of PMCA1-4 and Its Splice Variants at Sites A and C in Vestibular Tissue of Adult Rats

目的研究质膜钙ATP酶异构体1-4(plasma membrane Ca^(2+)-ATPase 1-4,PMCA1-4)在成年大鼠前庭组织的分布部位,及其A端和C端剪接变异体的表达类型。方法选择8周龄健康SD大鼠,解剖出内耳器官行前庭切片,同时取前庭椭圆囊斑和球囊斑提取总RNA。通过免疫荧光方法检测PMCA1-4在成年大鼠内耳前庭组织的表达部位,通过逆转录聚合酶链反应(RT-PCR)法检测PMCA1-4的A端和C端剪接变异体在成年大鼠前庭组织的表达类型。结果球囊和椭圆囊荧光染色切片中,于毛细胞和支持细胞的胞体外侧膜可见PMCA1表达,毛细胞纤毛中可见PMCA2强表达,毛细胞和支持细胞的胞体外侧膜可见PMCA3弱表达,PMCA4几乎不表达。4种PMCA亚型在球囊表达的剪接体分别为PMCA1x/b、PMCA2w/b、PMCA3z/(a,b)和PMCA4x/b,它们在椭圆囊的表达类型与球囊相同。结论PMCA1-4在成年大鼠前庭器官的表达部位存在差异,这4种PMCA亚型的剪接体类型也各不相同。这种差异性可能是为了满足前庭组织和亚细胞结构域对Ca2+调节的特殊需求。

Objective To detect the distribution sites of plasma membrane Ca^(2+)-ATPase 1-4(PMCA1-4)and the types of splice variants at sites A and C in adult rat vestibular tissues.Methods Healthy SD rats eight-week old were selected.The inner ear organs were dissected for vestibular sections,while vestibular macula sacculi and macula utriculi were isolated for total RNA extraction.The expression of PMCA1-4 in vestibular tissues of adult rat inner ear was detected by immunofluorescence,and the expression of A-terminal and C-terminal splice variants of PMCA1-4 in vestibular tissues of adult rat was detected by reverse transcription-polymerase chain reaction method.Results PMCA1 was expressed in the basolateral membrane of hair cells and supporting cells in saccule and utricle.PMCA2 was strongly expressed in the hair cell bundles of saccule and utricle.PMCA3 was weakly expressed in the basolateral membrane of hair cells and supporting cells in saccule and utricle.PMCA4 was poorly expressed in saccule and utricle.The four PMCA isoforms respectively expressed PMCA1x/b,PMCA2w/b,PMCA3z/(a,b)and PMCA4x/b in the saccule,their expression pattern in the utricle is the same as that in the saccule.Conclusion The distribution sites of PMCA1-4 varied in the vestibular organs of adult rats,and the spilce variants of the four PMCA subtypes were also variant.The distribution diversity is likely to associated with the special demands of Ca^(2+)regulation in vestibular tissues and subcellular domains.