Control of segmental expression of the cardiac-restricted ankyrin repeat protein gene by distinct regulatory pathways in murine cardiogenesis.
Control of segmental expression of the cardiac-restricted ankyrin repeat protein gene by distinct regulatory pathways in murine cardiogenesis.
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发表时间：
1999-10
期刊：
影响因子：
4.6
通讯作者：
Hai‐Chien Kuo;Ju Chen;P. Ruiz‐Lozano;Y. Zou;M. Nemer;K. Chien
中科院分区：
文献类型：
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作者：
Hai‐Chien Kuo;Ju Chen;P. Ruiz‐Lozano;Y. Zou;M. Nemer;K. Chien
尽管越来越多的证据表明心脏以节段的方式发育，但控制发育中的心脏中心肌细胞区域规范的分子机制仍然很大程度上未知。在本研究中，我们使用小鼠心脏限制性锚蛋白重复蛋白（CARP）基因作为模型系统来研究这些机制。 CARP 基因编码心脏基因表达的核协同调节因子，位于心脏同源盒基因 Nkx 2.5 的下游，是心肌细胞谱系的早期标记。我们已经证明，在心脏肥大期间，作为胚胎基因程序的一部分，该基因的表达在发育过程中被下调并被显着诱导。使用 lacZ/敲入小鼠和三个带有各种 CARP 启动子/lacZ 报告基因的转基因小鼠品系，我们鉴定了该基因的不同 5' 顺式调控元件，可以指导心脏节段特异性转基因表达，例如心房与心室以及左心室与右心室。最有趣的是，发现该基因的 213 个碱基对序列元件赋予圆锥干节段特异性转基因表达。使用转基因作为圆锥干节段特异性标记，我们能够记录心脏发生过程中圆锥干部分心肌细胞的发育命运。此外，我们还确定了该基因近端上游调控区的一个重要的 GATA-4 结合位点以及由 Nkx2.5 和 GATA-4 介导的协同转录调控。我们已经表明，这种协同调节依赖于 GATA-4 与其启动子中的同源 DNA 序列的结合，这表明 Nkx2.5 至少部分通过 GATA-4 控制 CARP 表达。
Although accumulating evidence suggests that the heart develops in a segmental fashion, the molecular mechanisms that control regional specification of cardiomyocytes in the developing heart remain largely unknown. In this study, we have used the mouse cardiac-restricted ankyrin repeat protein (CARP) gene as a model system to study these mechanisms. The CARP gene encodes a nuclear co-regulator for cardiac gene expression, which lies downstream of the cardiac homeobox gene, Nkx 2.5, and is an early marker of the cardiac muscle cell lineage. We have demonstrated that the expression of the gene is developmentally down regulated and dramatically induced as part of the embryonic gene program during cardiac hypertrophy. Using a lacZ/knock-in mouse and three lines of transgenic mouse harboring various CARP promoter/lacZ reporters, we have identified distinct 5' cis regulatory elements of the gene that can direct heart segment-specific transgene expression, such as atrial versus ventricular and left versus right. Most interestingly, a 213 base pair sequence element of the gene was found to confer conotruncal segment-specific transgene expression. Using the transgene as a conotruncal segment-specific marker, we were able to document the developmental fate of a subset of cardiomyocytes in the conotruncus during cardiogenesis. In addition, we have identified an essential GATA-4 binding site in the proximal upstream regulatory region of the gene and cooperative transcriptional regulation mediated by Nkx2.5 and GATA-4. We have shown that this cooperative regulation is dependent on binding of GATA-4 to its cognate DNA sequence in the promoter, which suggests that Nkx2.5 controls CARP expression, at least in part, through GATA-4.