共查询到20条相似文献,搜索用时 437 毫秒
1.
2.
3.
4.
5.
6.
Sox9基因是一个重要的转录调控因子,参与性别决定及软骨等多种组织和器官的发育过程。本研究利用简并引物扩增鲤鱼基因组DNA,首次发现在鲤鱼中存在两种形式的Sox9基因。二者在保守盒区编码的氨基酸序列相同,并都存在一个内含子,但内含子序列差异很大,分别长704bp和616bp。在此基础上采用RACE技术克隆了鲤鱼Sox9b基因的5’端和3’端,通过拼接获得了2447bp 的全长cDNA序列,编码428个氨基酸。其中96-174位共79个氨基酸为HMG保守盒。将鲤鱼Sox9b基因与三刺鱼等九种动物的氨基酸序列相比较发现,它们的同源性高达75%以上,显示Sox9 基因在进化中较保守。应用半定量RT-PCR技术对成体鲤鱼不同组织中Sox9b基因的表达进行了分析,结果表明该基因广泛表达,尤以脑及精巢中表达最为丰富。 相似文献
7.
Sox9基因是一个重要的转录调控因子,参与性别决定及软骨等多种组织和器官的发育过程。本研究利用简并引物扩增鲤鱼基因组DNA,首次发现在鲤鱼中存在两种形式的Sox9基因。二者在保守盒区编码的氨基酸序列相同,并都存在一个内含子,但内含子序列差异很大,分别长704bp和616bp。在此基础上采用RACE技术克隆了鲤鱼Sox9b基因的5’端和3’端,通过拼接获得了2447bp的全长cDNA序列。编码428个氨基酸。其中96—174位共79个氨基酸为HMG保守盒。将鲤鱼Sox9b基因与三刺鱼等九种动物的氨基酸序列相比较发现。它们的同源性高达75%以上,显示soz9基因在进化中较保守。应用半定量RT—PCR技术对成体鲤鱼不同组织中Sox9b基因的表达进行了分析。结果表明该基因广泛表达,尤以脑及精巢中表达最为丰富。 相似文献
8.
非编码DNA序列是指基因组中不编码蛋白质的DNA序列。这些序列可以结合调节因子、转录为功能性RNA、单独或协同地调节生理活动和病理过程。文章围绕基因表达调控作用, 总结了近几年非编码DNA序列的研究成果, 对其结构、功能和可能的作用机制进行了初步阐述, 介绍了目前鉴定非编码DNA序列中功能元件的计算方法和实验技术, 并对非编码DNA未来的研究进行了展望。 相似文献
9.
《生理科学进展》2014,(1)
<正>长非编码RNA是一种新的调节RNA,包括长200至1000000个碱基对的由DNA转录而来但无蛋白编码能力的RNA。最近,高通量转录组分析发现了人类基因组中大量的lncRNA。人类基因组中只有1.5%的蛋白编码蛋白,而大部分非编码调节原件都转录为非编码RNA。其中,lncRNA在发育、分化、代谢等生理过程中基因表达的各个水平都起调控作用。已有的报道发现,lncRNA可作为信号、脚手架以及基因转录和翻译中各种修饰过程的抑制剂或激活剂,并通过这些途径调控基因表达。近年来,lncRNA被视为基因转录调控中至关重要的一环。然而lncRNA在各种生理过程中的功能仍需进一步研究。 相似文献
10.
11.
The sea lamprey is an important model organism for investigating the evolutionary origins of vertebrates. As more vertebrate genome sequences are obtained, evolutionary developmental biologists are becoming increasingly able to identify putative gene regulatory elements across the breadth of the vertebrate taxa. The identification of these regions makes it possible to address how changes at the genomic level have led to changes in developmental gene regulatory networks and ultimately to the evolution of morphological diversity. Comparative genomics approaches using sea lamprey have already predicted a number of such regulatory elements in the lamprey genome. Functional characterisation of these sequences and other similar elements requires efficient reporter assays in lamprey. In this report, we describe the development of a transient transgenesis method for lamprey embryos. Focusing on conserved non-coding elements (CNEs), we use this method to investigate their functional conservation across the vertebrate subphylum. We find instances of both functional conservation and lineage-specific functional evolution of CNEs across vertebrates, emphasising the utility of functionally testing homologous CNEs in their host species. 相似文献
12.
Beaster-Jones L 《Briefings in functional genomics》2012,11(2):118-130
The origin of the vertebrates was a major event in the evolution of morphological diversity and the genetic mechanisms responsible for this diversity, once purely theoretical, can now be approached experimentally in the genome era. With a prototypical chordate genome, vertebrate-like development and simple morphology, amphioxus provides the appropriate model for investigating the origin of the vertebrates. Comparative genomics is revealing that both conservation and divergence of genes and cis-regulatory elements involved in developmental regulatory networks are required to shape different animal body plans. This article reviews the cis-regulatory studies performed in amphioxus, the discovery of conserved non-coding elements (CNEs) across the metazoans and the examination of amphioxus CNEs. Emerging ideas on the evolution of CNEs after large-scale genome duplication events and the state of cephalochordate genomics are also discussed. 相似文献
13.
Koh Onimaru 《Development, growth & differentiation》2020,62(5):326-333
How random DNA mutations have established the diverse morphology of extant vertebrates is one of the major challenges in evolutionary biology. Thanks to the recent advancement in DNA sequencing technologies, the genome sequences of many non-model species have been determined, which allows us to address previously inaccessible questions about gene regulatory evolution in vertebrates. In particular, the genome sequences of non-teleost ray-finned fishes and cartilaginous fishes offer clues about when and how vertebrates gained developmental enhancers related to morphological traits that were required for the water-to-land transition. In this review, I examine the evolutionary origin of conserved non-coding elements (CNEs), which often function as tissue-specific developmental enhancers, and discuss how CNEs are related to gene regulatory changes that caused the major morphological transitions of vertebrates. 相似文献
14.
15.
Vertebrate genomes contain thousands of conserved noncoding elements (CNEs) that often function as tissue-specific enhancers. In this study, we have identified CNEs in human, dog, chicken, Xenopus, and four teleost fishes (zebrafish, stickleback, medaka, and fugu) using elephant shark, a cartilaginous vertebrate, as the base genome and investigated the evolution of these ancient vertebrate CNEs (aCNEs) in bony vertebrate lineages. Our analysis shows that aCNEs have been evolving at different rates in different bony vertebrate lineages. Although 78-83% of CNEs have diverged beyond recognition ("lost") in different teleost fishes, only 24% and 40% have been lost in the chicken and mammalian lineages, respectively. Relative rate tests of substitution rates in CNEs revealed that the teleost fish CNEs have been evolving at a significantly higher rate than those in other bony vertebrates. In the ray-finned fish lineage, 68% of aCNEs were lost before the divergence of the four teleosts. This implicates the "fish-specific" whole-genome duplication in the accelerated evolution and the loss of a large number of both copies of duplicated CNEs in teleost fishes. The aCNEs are rich in tissue-specific enhancers and thus many of them are likely to be evolutionarily constrained cis-regulatory elements. The rapid evolution of aCNEs might have affected the expression patterns driven by them. Transgenic zebrafish assay of some human CNE enhancers that have been lost in teleosts has indicated instances of conservation or changes in trans-acting factors between mammals and fishes. 相似文献
16.
17.
Halligan DL Oliver F Guthrie J Stemshorn KC Harr B Keightley PD 《Molecular biology and evolution》2011,28(9):2651-2660
There are many more selectively constrained noncoding than coding nucleotides in the mammalian genome, but most mammalian noncoding DNA is subject to weak selection, on average. One of the most striking discoveries to have emerged from comparisons among mammalian genomes is the hundreds of noncoding elements of more than 200 bp in length that show absolute conservation among mammalian orders. These elements represent the tip of the iceberg of a much larger class of conserved noncoding elements (CNEs). Much evidence suggests that CNEs are selectively constrained and not mutational cold-spots, and there is evidence that some CNEs play a role in the regulation of development. Here, we quantify negative and positive selection acting in murine CNEs by analyzing within-species nucleotide variation and between-species divergence of CNEs that we identified using a phylogenetically independent comparison. The distribution of fitness effects of new mutations in CNEs, inferred from within-species polymorphism, suggests that CNEs receive a higher number of strongly selected deleterious mutations and many fewer nearly neutral mutations than amino acid sites of protein-coding genes or regulatory elements close to genes. However, we also show that CNEs experience a far higher proportion of adaptive substitutions than any known category of genomic sites in murids. The absolute rate of adaptation of CNEs is similar to that of amino acid sites of proteins. This result suggests that there is widespread adaptation in mammalian conserved noncoding DNA elements, some of which have been implicated in the regulation of crucially important processes, including development. 相似文献
18.
BackgroundMutations in the SHOX gene are responsible for Leri-Weill Dyschondrosteosis, a disorder characterised by mesomelic limb shortening. Recent investigations into regulatory elements surrounding SHOX have shown that deletions of conserved non-coding elements (CNEs) downstream of the SHOX gene produce a phenotype indistinguishable from Leri-Weill Dyschondrosteosis. As this gene is not found in rodents, we used zebrafish as a model to characterise the expression pattern of the shox gene across the whole embryo and characterise the enhancer domains of different CNEs associated with this gene.Conclusion/SignificanceOur results using whole zebrafish embryos have provided a more comprehensive picture of the expression pattern of the shox gene, and a better understanding of its regulation via deeply conserved noncoding elements. In particular, we identify additional tissues under the regulatory control of previously identified SHOX CNEs. We also demonstrate the importance of these CNEs in evolution by identifying duplicated shox CNEs and more deeply conserved sub-sequences within already identified CNEs. 相似文献
19.
Goode DK Callaway HA Cerda GA Lewis KE Elgar G 《Development (Cambridge, England)》2011,138(5):879-884
Within the vertebrate lineage, a high proportion of duplicate genes have been retained after whole genome duplication (WGD) events. It has been proposed that many of these duplicate genes became indispensable because the ancestral gene function was divided between them. In addition, novel functions may have evolved, owing to changes in cis-regulatory elements. Functional analysis of the PAX2/5/8 gene subfamily appears to support at least the first part of this hypothesis. The collective role of these genes has been widely retained, but sub-functions have been differentially partitioned between the genes in different vertebrates. Conserved non-coding elements (CNEs) represent an interesting and readily identifiable class of putative cis-regulatory elements that have been conserved from fish to mammals, an evolutionary distance of 450 million years. Within the PAX2/5/8 gene subfamily, PAX2 is associated with the highest number of CNEs. An additional WGD experienced in the teleost lineage led to two copies of pax2, each of which retained a large proportion of these CNEs. Using a reporter gene assay in zebrafish embryos, we have exploited this rich collection of regulatory elements in order to determine whether duplicate CNEs have evolved different functions. Remarkably, we find that even highly conserved sequences exhibit more functional differences than similarities. We also discover that short flanking sequences can have a profound impact on CNE function. Therefore, if CNEs are to be used as candidate enhancers for transgenic studies or for multi-species comparative analyses, it is paramount that the CNEs are accurately delineated. 相似文献
20.
Daniel L. Halligan Athanasios Kousathanas Rob W. Ness Bettina Harr Lél E?ry Thomas M. Keane David J. Adams Peter D. Keightley 《PLoS genetics》2013,9(12)
The contribution of regulatory versus protein change to adaptive evolution has long been controversial. In principle, the rate and strength of adaptation within functional genetic elements can be quantified on the basis of an excess of nucleotide substitutions between species compared to the neutral expectation or from effects of recent substitutions on nucleotide diversity at linked sites. Here, we infer the nature of selective forces acting in proteins, their UTRs and conserved noncoding elements (CNEs) using genome-wide patterns of diversity in wild house mice and divergence to related species. By applying an extension of the McDonald-Kreitman test, we infer that adaptive substitutions are widespread in protein-coding genes, UTRs and CNEs, and we estimate that there are at least four times as many adaptive substitutions in CNEs and UTRs as in proteins. We observe pronounced reductions in mean diversity around nonsynonymous sites (whether or not they have experienced a recent substitution). This can be explained by selection on multiple, linked CNEs and exons. We also observe substantial dips in mean diversity (after controlling for divergence) around protein-coding exons and CNEs, which can also be explained by the combined effects of many linked exons and CNEs. A model of background selection (BGS) can adequately explain the reduction in mean diversity observed around CNEs. However, BGS fails to explain the wide reductions in mean diversity surrounding exons (encompassing ∼100 Kb, on average), implying that there is a substantial role for adaptation within exons or closely linked sites. The wide dips in diversity around exons, which are hard to explain by BGS, suggest that the fitness effects of adaptive amino acid substitutions could be substantially larger than substitutions in CNEs. We conclude that although there appear to be many more adaptive noncoding changes, substitutions in proteins may dominate phenotypic evolution. 相似文献