Genomic organization of mouse ZAKI-4 gene that encodes ZAKI-4 α and β isoforms, endogenous calcineurin inhibitors, and changes in the expression of these isoforms by thyroid hormone in adult mouse brain and heart
Genomic organization of mouse ZAKI-4 gene that encodes ZAKI-4 α and β isoforms, endogenous calcineurin inhibitors, and changes in the expression of these isoforms by thyroid hormone in adult mouse brain and heart
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DOI：
10.1530/eje.0.1500371
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发表时间：
2004-03-01
影响因子：
5.8
通讯作者：
Murata, Y
中科院分区：
文献类型：
--
作者：
Mizuno, Y;Kanou, Y;Murata, Y
目的：在培养的人成纤维细胞中，ZAKI-4基因被鉴定为甲状腺激素反应基因。一个Zaki-4基因编码两种异构体。Zaki-4α和β都能抑制钙调神经磷酸酶的活性。Zaki-4α和β在N末端不同，在人体组织中表现出不同的分布特征。本研究的目的是阐明小鼠Zaki-4基因的组织结构，并确定甲状腺激素对体内Zaki-4亚型表达的影响。设计：克隆小鼠人Zaki-4α和β基因的同源物。荧光原位杂交和生物信息学分析确定基因组织。方法：从小鼠小脑中提取总RNA，通过RT-PCR方法克隆Zaki-4α和βcDNAs，然后快速扩增cDNAs。以添加丙基硫氧嘧啶的低碘饲料喂养小鼠2周，造成小鼠甲状腺功能低下。甲亢组(甲亢组)腹腔注射L-T-3；而另一组(甲状腺功能减退组)仅接受赋形剂治疗。结果与结论：小鼠Zaki-4α和βcDNA与人类同源异构体高度同源。该基因被定位在染色体17qC上。与人类6号染色体同线，人类Zaki-4基因所在的地方。与在人类中观察到的一样，Zaki-4αmRNA仅在脑中表达，而βmRNA也在其他组织中表达，如心脏和骨骼肌。甲减小鼠大脑皮层中Zaki-4α基因表达水平较低。注射L-T3后，心脏组织中ZAKI-4β基因表达增加，而其他组织中ZAKI-4α和β基因的表达均不受甲状腺状况的影响。这些结果表明，Zaki-4α及其异构体的表达在体内受甲状腺激素的调节，并且这种调节是同种异构体和组织特异性的。
Objective: ZAKI-4 was identified as a thyroid hormone-responsive gene in cultured human fibroblasts. A single ZAKI-4 gene encodes two isoforms. ZAKI-4 alpha and beta, both inhibiting calcineurin activity. ZAKI-4 alpha and beta differ at their N termini, and show distinct distribution profiles in human tissues. The aim of this study was to elucidate the organization of the mouse ZAKI-4 gene and to determine the effect of thyroid hormone on the expression of ZAKI-4 isoforms in vivo.Design: We cloned mouse homologues of human ZAKI-4 alpha and beta cDNA. Fluorescence in situ hybridization and bioinformatics analysis were employed to determine the gene organization. The effect of thyroid hormone on the expression of ZAKI-4 isoforms in mouse brain and heart was also studied.Methods: Total RNA extracted from mouse cerebellum was used to clone ZAKI-4 alpha and beta cDNAs by RT-PCR followed by rapid amplification of cDNA ends. Mice were rendered hypothyroid by feeding a low iodine diet supplemented with propylthiouracil for 2 weeks. In one group (hyperthyroid) L-T-3 was injected i.p. for the last 4 days whereas another group (hypothyroid) received vehicle only. Non-treated mice were controls.Results and conclusion: Mouse ZAKI-4 alpha and beta cDNAs were highly homologous to the human isoforms. The gene was mapped on chromosome 17qC. syntenic to human chromosome 6 where the human ZAKI-4 gene is located. As observed in human, ZAKI-4 alpha mRNA was expressed only in brain whereas beta mRNA was distributed in other tissues as well, such as heart and skeletal muscle. ZAKI-4 alpha mRNA was lower in the cerebral cortex of hypothyroid mice. Injection of L-T3 caused an increase in ZAKI-4 beta mRNA in heart: however, expression of neither ZAKI-4 alpha nor beta mRNA was influenced by thyroid status in other tissues. These results indicate that expression of ZAKI-4 alpha and isoforms is regulated by thyroid hormone in vivo, and the regulation is isoform- and tissue-specific.