Tripodi Grazia, Modica Rossana, Reina Cristina, Bianchi Giuseppe
Prassis-Sigma Tau Research Institute, Via Forlanini, 1, 20029 Settimo Milanese, Milan, Italy.
Biochem Biophys Res Commun. 2003 Mar 28;303(1):230-7. doi: 10.1016/s0006-291x(03)00330-9.
Genetic variants in Adducins, a family of cytoskeleton proteins (alpha, beta, and gamma) encoded by three genes, have been associated with primary hypertension in humans and in Milan hypertensive (MHS) rats. The present paper describes the identification of a rat beta 4 alternative splicing isoform differing from beta subunit for an in-frame insertion of 18 amino acids and showing a polymorphic site (R592W) between MHS and its normotensive control (MNS). Furthermore, we established a quantitative real-time PCR assay for analyzing the tissue expression of adducin gene family and determining whether any subunit transcript demonstrates altered expression during the development of MHS hypertension, especially in tissues relevant for the control of cardiovascular phenotypes (i.e., kidney, left ventricle, and large arteries). Among the three adducins only beta transcripts were modulated, in a tissue-specific manner, during the development of hypertension in MHS, compared to age-matched MNS controls. A 43% decrease in renal outer medulla was already present at the prehypertensive phase; a 70% decrease in femoral artery and 66% increase in left ventricle were observed after the development of hypertension. Surprisingly beta 4-Add, which is a minor component of total beta transcripts, is drastically reduced up to 88% in all MHS tissues. Alteration in beta-Add expression levels may account, at least in part, for the observed phenotypic changes in MHS hypertension.
内收蛋白是一类由三个基因编码的细胞骨架蛋白家族（α、β和γ），其基因变异已被证实与人类原发性高血压以及米兰高血压大鼠（MHS）相关。本文描述了一种大鼠β4可变剪接异构体的鉴定，该异构体与β亚基不同，有一个18个氨基酸的框内插入，并且在MHS及其正常血压对照（MNS）之间显示出一个多态性位点（R592W）。此外，我们建立了一种定量实时PCR检测方法，用于分析内收蛋白基因家族的组织表达，并确定在MHS高血压发展过程中，尤其是在与心血管表型控制相关的组织（即肾脏、左心室和大动脉）中，是否有任何亚基转录本的表达发生改变。在MHS高血压发展过程中，与年龄匹配的MNS对照相比，在三个内收蛋白中，只有β转录本以组织特异性方式受到调节。在高血压前期，肾外髓质中的β转录本已经减少了43%；高血压发展后，股动脉中的β转录本减少了70%，左心室中的β转录本增加了66%。令人惊讶的是，β4-Add作为总β转录本的次要成分，在所有MHS组织中急剧减少，高达88%。β-Add表达水平的改变可能至少部分解释了在MHS高血压中观察到的表型变化。
