Printed in U.S.A. Copyright © 2001 by The Endocrine Society Characterization of Two Forms of Cocaine- and Amphetamine-Regulated Transcript (CART) Peptide Precursors in Goldfish: Molecular Cloning and Distribution, Modulation of Expression by Nutritional S
Printed in U.S.A. Copyright © 2001 by The Endocrine Society Characterization of Two Forms of Cocaine- and Amphetamine-Regulated Transcript (CART) Peptide Precursors in Goldfish: Molecular Cloning and Distribution, Modulation of Expression by Nutritional S
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DOI：
10.1210/endo.142.12.8519
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发表时间：
2001-12
期刊：
影响因子：
4.8
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中科院分区：
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从金鱼脑中鉴定出编码可卡因和安非他明调节转录物（CART）肽前体两种形式的互补DNA，并命名为CART I和CART II。每个cDNA包含信号肽序列、推定的CART样肽和羧基末端延伸肽。I型编码117个氨基酸的pro-CART，而II型编码120个氨基酸的pro-CART。这两种形式类似于哺乳动物CART肽。每个金鱼CART前体由基因组DNA内的三个外显子编码，其中两个内含子被中断。RT-PCR、狭缝印迹和北方印迹分析表明，I型和II型前体的mRNA具有广泛的分布。I型和II型存在于脑、垂体、眼、性腺和肾中。I型也存在于鳃中。在脑中，I型在嗅球和下丘脑中占优势，II型在视顶盖中占优势。食物剥夺96小时诱导端脑视前区，下丘脑和嗅球中的I型mRNA水平下降，嗅球中的II型mRNA表达下降。mRNA水平的增加，观察到2小时后，在嗅球和下丘脑的形式I餐后，而没有餐后变化，形式II的mRNA水平进行了观察。脑室内注射单独的人CART诱导食物摄入量显著减少。注射瘦素加强CART处理的鱼的摄食行为和食物摄入的抑制。中枢注射瘦素可诱导视顶盖、下丘脑和嗅球CART I mRNA的表达增加，但对大脑CART II mRNA的表达无影响。这些结果表明，CART肽作为瘦素调节的饱足因子在金鱼，他们可能有其他的生理作用，除了喂养，可能在感官信息处理。
Complementary DNAs encoding two forms of cocaine- and amphetamine-regulated transcript (CART) peptide precursors were identified from goldfish brain and named CART I and CART II. Each cDNA contains a signal peptide sequence, the putative CART-like peptide, and a carboxy-terminal extension peptide. Form I encodes a 117-amino acid pro-CART, whereas form II encodes a 120-amino acid pro-CART. Both forms resemble mammalian CART peptides. Each goldfish CART precursor is encoded by three exons interrupted by two introns within genomic DNA. RT-PCR, slot blot, and Northern blot analysis showed that the mRNAs for form I and II precursors have a widespread distribution. Form I and II are present in the brain, pituitary, eye, gonads, and kidney. Form I is also present in the gill. In the brain, form I is predominant in the olfactory bulb and hypothalamus, and form II is predominant in the optic tectum. Food deprivation for 96 h induced a decrease in form I mRNA levels in the telencephalon-preoptic region, hypothalamus, and olfactory bulb and in form II mRNA expression in the olfactory bulb. An increase in mRNA levels was observed 2 h following a meal in the olfactory bulbs and hypothalamus for form I whereas no postprandial changes in form II mRNA levels were observed. Intracerebroventricular injections of human CART alone induced a significant decrease in food intake. Injections of leptin reinforced the inhibition of feeding behavior and food intake seen in CART-treated fish. Central injection of leptin induced an increase in CART I mRNA in the optic tectum, hypothalamus, and olfactory bulbs but had no effect on CART II mRNA expression in the brain. These results suggest that CART peptides act as leptin-regulated satiety factors in goldfish and that they might have other physiological roles besides feeding, possibly in sensory information processing.