Magnesium Deficiency: Global Gene Expression Study

描述（由申请人提供）：镁（Mg2+）是细胞中第二丰富的阳离子。由于Mg2+在数百种酶促反应中作为辅助因子，它对许多生物活动有深远的影响，包括DNA和蛋白质合成、离子运输、细胞内信号转导以及细胞生长和分化。因此，Mg2+缺乏与各种疾病状态，如动脉粥样硬化、高血压、糖尿病、哮喘和酒精中毒有关，这并不奇怪。然而，我们对Mg2+稳态的理解远远落后于其他阳离子，如Ca2+， Na+， K+和H+，主要是因为Mg2+的转运体尚未在分子水平上确定。此外，关于Mg2+缺乏对基因表达的影响，特别是其在各种病理条件下的作用的研究很少。利用cDNA微阵列进行基因表达谱分析是鉴定参与特定细胞或疾病过程的基因的一种强有力的方法。我们建议利用这项技术来鉴定参与镁稳态的基因，并阐明镁缺乏导致各种疾病状态的机制。通过比较正常小鼠与缺镁小鼠选择器官的整体基因表达模式，应该有可能确定参与镁稳态的基因，例如编码镁转运蛋白的基因。在缺镁条件下异常表达的基因也应该被确定。这应该能让我们更好地理解镁在健康和疾病中的作用。在Aims 1和Aims 2中，商业cDNA微阵列将分别用于研究急性和慢性镁缺乏对基因表达的影响。在Aim 3中，将从补镁和缺镁小鼠的各个器官中构建抑制减法杂交文库。然后，文库中的克隆将用于构建用于基因表达谱的定制cDNA微阵列。这种技术的结合应该导致在缺镁期间差异表达的所有基因的鉴定。

DESCRIPTION (provided by applicant): Magnesium (Mg2+) is the second most abundant cation in cells. Because Mg2+ serves as a cofactor in hundreds of enzymatic reactions, it has a profound influence on many biological activities including DNA and protein synthesis, ion transport, intracellular signal transduction, and cell growth and differentiation. Consequently, it is not surprising that Mg2+ deficiency has been implicated in various disease states such as atherosclerosis, hypertension, diabetes, asthma, and alcoholism. Yet, our understanding of Mg2+ homeostasis lags far behind that of other cations such as Ca2+, Na+, K+, and H+, largely because the transporters of Mg2+ have not been identified at the molecular level. In addition, little work has been conducted concerning the effects of Mg2+ deficiency on gene expression, especially with respect to its role in various pathological conditions. Gene expression profiling using cDNA microarrays represents a powerful method for identifying genes involved in specific cellular or disease processes. We propose to use this technology to identify genes involved in magnesium homeostasis and to elucidate the mechanisms by which magnesium deficiency leads to various disease states. By comparing global gene expression patterns of select organs of normal mice to their counterparts in magnesium-deficient mice, it should be possible to identify genes involved in magnesium homeostasis, such as those encoding magnesium transporters. Genes that are aberrantly expressed under magnesium-deficient conditions should also be identified. This should lead to a better understanding of magnesium's role in health and disease. In Aims 1 and 2 commercial cDNA microarrays will be used to investigate the effects of acute and chronic magnesium deficiency on gene expression, respectively. In Aim 3 suppression subtraction hybridization libraries will be constructed from various organs of magnesium-replete and magnesium-deficient mice. Clones from the library will then be used to construct custom cDNA microarrays for gene expression profiling. This combination of techniques should lead to the identification of all genes that are differentially expressed during magnesium deficiency.