Intronic cis-regulatory modules mediate tissue-specific and microbial control of angptl4/fiaf transcription.
Intronic cis-regulatory modules mediate tissue-specific and microbial control of angptl4/fiaf transcription.
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DOI：
10.1371/journal.pgen.1002585
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发表时间：
2012
期刊：
影响因子：
4.5
通讯作者：
Rawls JF
中科院分区：
文献类型：
--
作者：
Camp JG;Jazwa AL;Trent CM;Rawls JF
肠道微生物群增强膳食能量收获，导致脂肪组织中脂肪储存增加。这种作用部分是由微生物抑制称为血管生成素样4（Angptl4/Fiaf）的脂蛋白脂肪酶的循环抑制剂的肠上皮表达引起的。为了确定Angptl4转录的丝氨酸特异性和微生物控制的顺式调节机制，我们利用了斑马鱼系统，其中可以在活的、透明的和无菌脊椎动物中快速分析宿主调节DNA。我们发现斑马鱼angptl4在多种组织中转录，包括肝脏、胰岛和肠上皮，这与其哺乳动物同源物相似。斑马鱼angptl4在肠道上皮中也在微生物群定殖时被特异性抑制。体内转基因报告基因测定鉴定了angptl4内含子3内足以驱动肝脏、胰岛β细胞或肠上皮细胞中表达的离散组织特异性调节模块。比较序列分析和异源功能测定angptl4内含子3序列从12硬骨鱼种揭示了胰岛和肠道调节模块的差异进化。高分辨率的功能定位和定点诱变确定了肠道活动所需的最小调控序列。引人注目的是，微生物群抑制了与内源性angptl4基因相似的精氨酸特异性调控模块的转录活性。这些结果表明，微生物群可能通过抑制精氨酸特异性转录增强子的活性来调节宿主肠道Angptl4蛋白表达和外周脂肪储存。该研究为理解微生物信号如何与组织特异性调控网络相互作用以控制宿主基因转录的活性和进化提供了有用的范例。最近的研究表明，肠道中的微生物群落调节脂肪储存。微生物通过抑制Angptl4基因的表达部分地引起这种反应，Angptl4基因编码脂肪储存的分泌抑制剂。尽管Angptl4在多种组织中表达，但微生物抑制仅发生在肠中。为了确定微生物是如何控制脂肪储存的，我们必须阐明Angptl4表达的丝氨酸特异性和微生物调节的潜在机制。在这里，我们利用斑马鱼模型的独特功能来定义控制angptl4表达的调控DNA序列。我们的研究结果表明，不同的DNA调控区域内的angptl4基因介导的angptl4在肠道和其他组织中的表达。通过评估angptl4调控区的进化，并对其进行结构-功能分析，我们确定了肠表达所需的离散DNA序列。引人注目的是，微生物抑制了与内源性angptl4基因相似的精氨酸特异性调节区的活性。因此，肠道微生物可能通过抑制由丝氨酸特异性转录调控区解释的信号传导途径来调节angptl4的产生。我们的研究结果为肠道微生物如何影响脂肪储存和促进肥胖的发展提供了新的机制见解。
The intestinal microbiota enhances dietary energy harvest leading to increased fat storage in adipose tissues. This effect is caused in part by the microbial suppression of intestinal epithelial expression of a circulating inhibitor of lipoprotein lipase called Angiopoietin-like 4 (Angptl4/Fiaf). To define the cis-regulatory mechanisms underlying intestine-specific and microbial control of Angptl4 transcription, we utilized the zebrafish system in which host regulatory DNA can be rapidly analyzed in a live, transparent, and gnotobiotic vertebrate. We found that zebrafish angptl4 is transcribed in multiple tissues including the liver, pancreatic islet, and intestinal epithelium, which is similar to its mammalian homologs. Zebrafish angptl4 is also specifically suppressed in the intestinal epithelium upon colonization with a microbiota. In vivo transgenic reporter assays identified discrete tissue-specific regulatory modules within angptl4 intron 3 sufficient to drive expression in the liver, pancreatic islet β-cells, or intestinal enterocytes. Comparative sequence analyses and heterologous functional assays of angptl4 intron 3 sequences from 12 teleost fish species revealed differential evolution of the islet and intestinal regulatory modules. High-resolution functional mapping and site-directed mutagenesis defined the minimal set of regulatory sequences required for intestinal activity. Strikingly, the microbiota suppressed the transcriptional activity of the intestine-specific regulatory module similar to the endogenous angptl4 gene. These results suggest that the microbiota might regulate host intestinal Angptl4 protein expression and peripheral fat storage by suppressing the activity of an intestine-specific transcriptional enhancer. This study provides a useful paradigm for understanding how microbial signals interact with tissue-specific regulatory networks to control the activity and evolution of host gene transcription. Recent studies have revealed that the community of microorganisms residing in the intestine regulates fat storage. Microbes evoke this response in part by suppressing expression of the Angptl4 gene, which encodes a secreted inhibitor of fat storage. Although Angptl4 is expressed in multiple tissues, microbial suppression occurs only in the intestine. To determine how microbes control fat storage, we must elucidate the mechanisms underlying intestine-specific and microbial regulation of Angptl4 expression. Here, we take advantage of the unique features of the zebrafish model to define the regulatory DNA sequences controlling angptl4 expression. Our results reveal that different DNA regulatory regions within the angptl4 gene mediate expression of angptl4 in the intestine and other tissues. By assessing the evolution of angptl4 regulatory regions and subjecting them to structure-function analyses, we identify discrete DNA sequences that are required for intestinal expression. Strikingly, microbes suppress the activity of the intestine-specific regulatory region similar to the endogenous angptl4 gene. Therefore, intestinal microbes might regulate angptl4 production by suppressing the signaling pathway interpreted by an intestine-specific transcriptional regulatory region. Our results provide new mechanistic insights into how intestinal microbes might influence fat storage and contribute to the development of obesity.
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影响因子：
14.9
作者：
Chekmenev DS;Haid C;Kel AE
通讯作者：
Kel AE
影响因子：
4.5
作者：
Bertrand S;Thisse B;Tavares R;Sachs L;Chaumot A;Bardet PL;Escrivà H;Duffraisse M;Marchand O;Safi R;Thisse C;Laudet V
通讯作者：
Laudet V
影响因子：
29.4
作者：
Camp JG;Kanther M;Semova I;Rawls JF
通讯作者：
Rawls JF
影响因子：
20.1
作者：
Cazes, Aurelie;Galaup, Ariane;Monnot, Catherine
通讯作者：
Monnot, Catherine
DOI：
10.1098/rstb.2005.1669
发表时间：
2005-07-29
影响因子：
6.3
作者：
Felsenstein, J
通讯作者：
Felsenstein, J