The evolution of Dscam genes across the arthropods.
The evolution of Dscam genes across the arthropods.
复制标题
DOI：
10.1186/1471-2148-12-53
复制
发表时间：
2012-04-13
影响因子：
3.4
通讯作者：
Bravo IG
中科院分区：
文献类型：
--
作者：
Armitage SA;Freiburg RY;Kurtz J;Bravo IG
创造表型多样性的一种方法是通过前体mrna的选择性剪接。唐氏综合症细胞粘附分子（Dscam-hv）是一种进化出高度可变形式的基因，它在果蝇中可以通过互斥的选择性剪接产生数千种同种异构体。该蛋白的细胞外区域由三个可变外显子簇编码，每个外显子簇包含多个外显子变体。这种蛋白质对神经线路至关重要，因为轴突引导需要体细胞水平的极端变异性，而且它在免疫中发挥作用，这种变异性被假设与不同抗原的识别有关。在整个pancrustaceae中都发现了Dscam-hv。此外，还发现了三个相似的非高变dscam样基因。本研究采用生物信息学方法，建立隐马尔可夫模型，在物种间搜索Dscam基因的假定同源物和高可变的可选剪接外显子，并推断它们之间的系统发育关系。我们的目的是研究Dscam同源物是否存在于两侧门之外，Dscam-hv的起源是否可能在pancrustaceae之外，当Dscam-hv同源物出现时，每个外显子簇中有多少个选择性剪接的外显子簇存在于最常见的最近祖先中，以及这些集群是如何进化的。我们的研究结果表明，Dscam基因的起源可能是在刺胞目和两侧门分裂之后，并支持了Dscam- v起源于pancrustaceae共同祖先的假设。我们的Dscam基因家族成员的系统发育显示了六个得到良好支持的分支：五个包含Dscam-like基因，一个包含所有Dscam-hv基因，第七个分支包含蛛形动物的Dscam基因。此外，外显子群似乎经历了不同的进化历史。Dscam基因在昆虫和蛛形动物基因组中经历了独立的复制事件，这增加了在Dscam-hv基因中发生的更著名的串联复制。因此，两种形式的基因扩展似乎在这个基因家族中活跃。这个动态基因家族的进化史将进一步展开，从更多不同群体的物种基因组变得可用。
One way of creating phenotypic diversity is through alternative splicing of precursor mRNAs. A gene that has evolved a hypervariable form is Down syndrome cell adhesion molecule (Dscam-hv), which in Drosophila melanogaster can produce thousands of isoforms via mutually exclusive alternative splicing. The extracellular region of this protein is encoded by three variable exon clusters, each containing multiple exon variants. The protein is vital for neuronal wiring where the extreme variability at the somatic level is required for axonal guidance, and it plays a role in immunity where the variability has been hypothesised to relate to recognition of different antigens. Dscam-hv has been found across the Pancrustacea. Additionally, three paralogous non-hypervariable Dscam-like genes have also been described for D. melanogaster. Here we took a bioinformatics approach, building profile Hidden Markov Models to search across species for putative orthologs to the Dscam genes and for hypervariable alternatively spliced exons, and inferring the phylogenetic relationships among them. Our aims were to examine whether Dscam orthologs exist outside the Bilateria, whether the origin of Dscam-hv could lie outside the Pancrustacea, when the Dscam-like orthologs arose, how many alternatively spliced exons of each exon cluster were present in the most common recent ancestor, and how these clusters evolved. Our results suggest that the origin of Dscam genes may lie after the split between the Cnidaria and the Bilateria and supports the hypothesis that Dscam-hv originated in the common ancestor of the Pancrustacea. Our phylogeny of Dscam gene family members shows six well-supported clades: five containing Dscam-like genes and one containing all the Dscam-hv genes, a seventh clade contains arachnid putative Dscam genes. Furthermore, the exon clusters appear to have experienced different evolutionary histories. Dscam genes have undergone independent duplication events in the insects and in an arachnid genome, which adds to the more well-known tandem duplications that have taken place within Dscam-hv genes. Therefore, two forms of gene expansion seem to be active within this gene family. The evolutionary history of this dynamic gene family will be further unfolded as genomes of species from more disparate groups become available.
登录
查看更多内容
影响因子：
2.9
作者：
Chou, Pin-Hsiang;Chang, Hao-Shuo;Wang, K. C. Han-Ching
通讯作者：
Wang, K. C. Han-Ching
影响因子：
64.8
作者：
Clark, Andrew G.;Eisen, Michael B.;MacCallum, Iain
通讯作者：
MacCallum, Iain
影响因子：
9.8
作者：
Dong, Yuemei;Taylor, Harry E;Dimopoulos, George
通讯作者：
Dimopoulos, George
影响因子：
16.2
作者：
Fuerst, Peter G.;Bruce, Freyja;Tian, Miao;Wei, Wei;Elstrott, Justin;Feller, Maria B.;Erskine, Lynda;Singer, Joshua H.;Burgess, Robert W.
通讯作者：
Burgess, Robert W.
DOI：
10.1006/bbrc.2001.5214
发表时间：
2001-07-20
影响因子：
3.1
作者：
Agarwala, KL;Ganesh, S;Yamakawa, K
通讯作者：
Yamakawa, K