Pineal Regulation: Molecular basis of development

松果体调节：发育的分子基础

• 批准号: 8941521
• 负责人: David Klein
• 金额: $ 0.52万
• 依托单位: EUNICE KENNEDY SHRIVER NATIONAL INSTITUTE OF CHILD HEALTH & HUMAN DEVELOPMENT
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8941521
• 关键词: Acetyl Coenzyme A; Acetylation; Acetyltransferase; Adult; Affect; Age-Months; Anterior; BHLH Protein; Binding; Biological; Brain; Catalysis; Cells; Chronobiology Disorders; Cre-LoxP; Development; Disease; Electroretinography; Elements; Embryo; Endocrine; Enzymes; Event; Evolution; Exhibits; Eye Development; Fishes; Gene Chips; Gene Duplication; Gene Expression; Gene Expression Profile; Genes; Genetic Recombination; Genome; Goals; Histologic; Homeobox; Homeostasis; Knock-out; Knockout Mice; Learning; Light; Maintenance; Melatonin; Microarray Analysis; Modeling; Molecular; Molecular Evolution; Monitor; Mutate; Neural Fold; Pattern; Phenethylamines; Phenotype; Photoreceptors; Physiological; Pineal gland; Pinealocyte; Play; Positioning Attribute; Process; Production; Proteins; Psyche structure; Quantitative Reverse Transcriptase PCR; RNA Interference; Rattus; Regulation; Regulatory Element; Research; Retina; Retinal; Retinal Degeneration; Retinal Diseases; Retinal Photoreceptors; Role; Sea Bream; Serotonin; Sleep; Specificity; Structure; Structure-Activity Relationship; Substrate Specificity; Testing; Tissues; Transcript; Undifferentiated; Vertebrate Photoreceptors; Vertebrates; Work; base; duplicate genes; immune function; interest; neurodevelopment; paralogous gene; postnatal; preference; prevent; promoter; recombinase; selective expression; teleost fish; three-dimensional modeling; transcription factor

Rax: Retina and anterior neural fold homeobox (Rax) gene encodes a transcription factor essential for vertebrate eye development. Recent microarray studies indicate that Rax is expressed in the adult rat pineal gland and retina. The present study reveals that Rax expression levels in the rat change significantly during retinal development with a peak occurring at embryonic day 18, whereas Rax expression in the pineal is relatively delayed and not detectable until embryonic day 20. In both tissues, Rax is expressed throughout postnatal development into adulthood. In the mature rat pineal gland, the abundance of Rax transcripts increases 2-fold during the light period with a peak occurring at dusk. These findings are consistent with the evidence that Rax is of functional importance in eye development and suggest a role of Rax in the developing pineal gland. In addition, it would appear possible that Rax contributes to phenotype maintenance in the mature retina and pineal gland and may facilitate 24-h changes in the pineal transcriptome.(From Rhode et al., 2011). NeuroD: NeuroD1 encodes a basic helix-loop-helix transcription factor involved in the development of neural and endocrine structures, including the retina and pineal gland. To determine the effect of NeuroD1 knockout in these tissues, a Cre/loxP recombination strategy was used to target a NeuroD1 floxed gene and generate NeuroD1 conditional knockout (cKO) mice. Tissue specificity was conferred using Cre recombinase expressed under the control of the promoter of Crx, which is selectively expressed in the pineal gland and retina. At 2 months of age, NeuroD1 cKO retinas have a dramatic reduction in rod- and cone-driven electroretinograms and contain shortened and disorganized outer segments; by 4 months, NeuroD1 cKO retinas are devoid of photoreceptors. In contrast, the NeuroD1 cKO pineal gland appears histologically normal. Microarray analysis of 2-month-old NeuroD1 cKO retina and pineal gland identified a subset of genes that were affected 2-100-fold; in addition, a small group of genes exhibit altered differential night/day expression. Included in the down-regulated genes are Aipl1, which is necessary to prevent retinal degeneration, and Ankrd33, whose protein product is selectively expressed in the outer segments. These findings suggest that NeuroD1 may act through Aipl1 and other genes to maintain photoreceptor homeostasis. Molecular Evolution: ArylalkylamineN-acetyltransferase (AANAT) catalyzes the transfer of an acetyl group from acetyl coenzyme A (AcCoA) to arylalkylamines, including indolethylamines and phenylethylamines. Multiple aanats are present in teleost fish as a result of whole genome and gene duplications. Fish aanat1a and aanat2 paralogs display different patterns of tissue expression and encode proteins with different substrate preference: AANAT1a is expressed in the retina, and acetylates both indolethylamines and phenylethylamines; while AANAT2 is expressed in the pineal gland, and preferentially acetylates indolethylamines. The two enzymes are therefore thought to serve different roles. Here, the molecular changes that led to their specialization were studied by investigating the structure-function relationships of AANATs in the gilthead seabream (sb, Sperus aurata). Acetylation activity of reciprocal mutated enzymes pointed to specific residues that contribute to substrate specificity of the enzymes. Inhibition tests followed by complementary analyses of the predicted three-dimensional models of the enzymes, suggested that both phenylethylamines and indolethylamines bind to the catalytic pocket of both enzymes. These results suggest that substrate selectivity of AANAT1a and AANAT2 is determined by the positioning of the substrate within the catalytic pocket, and its accessibility to catalysis. This illustrates the evolutionary process by which enzymes encoded by duplicated genes acquire different activities and play different biological roles. (From Zilberman-Peled et al., 2011).

RAX：视网膜和前神经褶皱同源物（RAX）基因编码脊椎动物眼发育至关重要的转录因子。最近的微阵列研究表明，RAX在成年大鼠松果体和视网膜中表达。本研究表明，在视网膜发育过程中，大鼠中的RAX表达水平发生了显着变化，在胚胎第18天发生了峰值，而松果的RAX表达相对延迟，直到胚胎第20天都无法检测到。在这两个组织中，RAX在整个后期发育均表达。在成熟的大鼠松果体中，在光周期内，RAX转录物的丰度增加了2倍，黄昏在峰值。这些发现与RAX在眼睛发育中具有功能重要性的证据是一致的，并暗示了RAX在发育中的松果体中的作用。此外，RAX似乎有可能有助于成熟的视网膜和松果体中的表型维持，并有助于促进松果体转录组的24小时变化。（Rhode等，2011）。 Neurod：Neurod1编码参与神经和内分泌结构（包括视网膜和松果体）发展的基本螺旋 - 环螺旋转录因子。为了确定这些组织中NeuroD1敲除的影响，使用CRE/LOXP重组策略来靶向神经1的floxed基因并产生Neurod1条件敲除（CKO）小鼠。使用在CRX启动子的控制下表达的CRE重组酶赋予组织特异性，该酶在松果体和视网膜中选择性表达。在2个月大时，NeuroD1 CKO视网膜的杆和锥体驱动的电视图的降低显着降低，并且包含缩短和混乱的外部段。到4个月，NeuroD1 CKO视网膜没有光感受器。相反，NeuroD1 CKO松果体在组织学上似乎正常。对2个月大的Neurod1 CKO视网膜和松果体的微阵列分析确定了一部分受影响2-100倍的基因；此外，一小部分基因表现出改变的差异夜/白天表达。在下调的基因中包括AIPL1，这对于预防视网膜变性是必不可少的，Ankrd33的蛋白产物在外部段中有选择地表达。这些发现表明，NeuroD1可以通过AIPL1和其他基因作用以维持感光体稳态。 分子进化： 芳基烷基胺 - 乙酰转移酶（AANAT）催化乙酰基从乙酰基辅酶A（ACCOA）转移到芳基烷基胺，包括吲哚甲胺和苯甲胺。由于整个基因组和基因重复，硬骨鱼中存在多个AANAT。 FISH AANAT1A和AANAT2旁系同源物显示出不同的组织表达模式，并用不同的底物偏好编码蛋白质：AANAT1A在视网膜中表达，乙酰化乙酰化氨基甲胺和苯基甲胺均表达。而AANAT2在松果体中表达，优先乙酰氨基氨基胺。因此，这两种酶被认为发挥了不同的作用。在这里，通过研究了吉尔特黑德·Seabream（SB，sperus aurata）中AANAT的结构 - 功能关系来研究导致其专业化的分子变化。倒数突变酶的乙酰化活性指向有助于酶底物特异性的特定残基。抑制测试，然后对预测的三维模型进行互补分析，表明苯甲胺和吲哚甲胺都与这两种酶的催化口袋结合。这些结果表明，AANAT1A和AANAT2的底物选择性取决于底物在催化口袋中的定位及其催化性的可及性。这说明了通过重复基因编码的酶获得不同的活性并扮演不同的生物学作用。 （摘自Zilberman-Peled等，2011）。