Pineal Regulation: Developmental and Circadian Changes in the Transcriptome

全球基因表达分析：松果体基因表达特征的研究正在进行中。第一阶段涉及对大鼠松果体的分析：利用微阵列基因表达研究啮齿动物松果体转录组。比较中午和午夜的表达谱发现，全球1000个基因的表达变化了2倍，其中2/3在夜间增加。其中，400个基因的表达增加了4倍；器官培养的研究表明，在几乎所有的病例中，高度上调的基因的表达都是通过去甲肾上腺素或环核苷酸类似物诱导的。这些发现与NE-环核苷酸信号是导致夜间基因表达增加的主要机制相一致。然而，也很清楚还有其他机制参与其中，因为少数高节律基因不被去甲肾上腺素诱导或被弱诱导。将松果体中的基因表达水平与其他组织中的中位数进行比较，发现松果体中有一组&gt；300基因的表达水平是松果体的8倍。最高表达基因的一个重要子集编码与褪黑素合成和这一过程的控制有关的蛋白质，包括通过肾上腺素能受体和第二信使(包括环核苷酸、钙离子和磷脂)进行信号传递。高表达基因簇与甲状腺激素、维甲酸、谷氨酸等细胞生物学有关，与金属离子稳态、膜转运和免疫反应有关。其他高度和/或有节律性表达的基因也编码转录因子、离子通道、转运体、受体、调节分子和分泌产物，这些都是以前在松果体文献中没有出现过的。松果体基因表达谱与其他几个组织的比较进一步证明，松果体与视网膜最相似的是扩大了仅在这两个组织中高度表达的基因的数量。这项研究表明，松果体生物学的控制比之前认为的要复杂得多，松果体和视网膜中高表达基因的数量比之前认为的要多，并提供了分子证据来怀疑松果体可能在高度保守的褪黑素产生作用之外发挥作用。继对啮齿动物松果体的研究之后，还对猴子和人类的松果体进行了类似的研究，以确定这三种组织中基因表达模式的相似性。 对啮齿动物松果体的分析结果引发了许多研究，其中一些研究已经发表，重点关注微阵列研究中突出的基因。HD000095-37中详细介绍了一个示例。 这项工作正在使用RNA序列技术进行扩展，除了注释基因外，还将重点放在miRNA和长的非编码RNA上。

Analysis of global gene expression: Studies are in progress which have characterized gene expression in the pineal gland. The first stage has involved analysis of the rat pineal gland: The rodent pineal transcriptome was investigated using microarray gene expression. Comparison of midday and midnight expression profiles revealed that a global >2-fold change in the expression of 1000 genes, 2/3 of which increase at night. Among these, 400 increase >4- fold in expression; studies in organ culture reveal that in nearly all cases, the expression of the highly upregulated genes is induced by treatment with NE or cyclic nucleotide analogs. These findings are consistent with the conclusion that NE-cyclic nucleotide signaling is the primary mechanism responsible for the nocturnal increase in gene expression. However, it is also clear that other mechanisms are involved, because a small number of highly rhythmic genes are not induced or are weakly induced by NE treatment. Comparison of the level of gene expression in the pineal gland to the median expression in other tissues indicates that a set of > 300 genes are expressed >8- fold higher in the pineal gland. A significant subset of the most highly expressed genes encode proteins involved in melatonin synthesis and the control of this process, including signalling via adrenergic receptors and second messengers including cyclic nucleotides, Ca++ and phospholipids. Clusters of highly expressed genes are associated with the cellular biology of thyroid hormone, retinoid acid, glutamate biology; and, with metal ion homeostasis, membrane trafficking, and the immune response. Other highly and/or rhythmically expressed genes also encode transcription factors, ion channels, transporters, receptors, regulatory molecules and secreted products that have not previously appeared in the pineal literature. Comparison of the pineal gene expression profile to that of several other tissues adds to the evidence that the pineal gland is most similar to the retina by expanding the number of genes that are highly expressed exclusively in these two tissues. This study indicates that control of pineal biology is significantly more complex than previously thought, that the number of highly expressed genes in the pineal gland and retina is higher than previously thought, and also provides molecular evidence to suspect that the gland might function outside of the highly conserved role it plays in melatonin production. The work on the rodent pineal gland is being followed up with similar work on the pineal gland of the monkey and human, so as to determine the similarity of the patterns of gene expression in these three tissues. The results of the analysis of the rodent pineal gland has triggered a number of studies, some of which have been published, which have focused on genes that have been highlighted by the microarray studies. An example is detailed in HD000095-37. This work is being extended using RNA Seq technology, with focus on miRNA and long noncoding RNAs in addition to annotated genes.