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eiieen

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[求助] 求剪接图解释

求专业术语按几个箭头指向解释这个剪接图,2个外显子增强子和1个内含子增强子等怎么作用的。谢谢
求剪接图解释
剪接.jpg
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凌波丽

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eiieen: 金币+2 2013-06-26 08:58:56
eiieen: 金币+3 2013-06-26 09:04:47
gyesang: 金币+2, 鼓励回帖应助! 2013-06-26 12:38:35
你就是这样提问的吗!?intronic splicing enhancer,exonic splicing enhancer的全称都不能明确写出吗!?

我现在知道intronic splicing enhancer,exonic splicing enhancer是分别在于一些intron和exon上的enhancer,有些特定的反式因子与其结合,按照一般的enhancer的作用机理(成环假说、扭曲假说、滑动假说和Oozing假说)影响可变剪接过程。

“Positive-acting splicing regulatory sequences generally can be classified by their location in either exons or introns. Exonic splicing enhancers are sequences, found in certain exons, that can stimulate spliceosome assembly at the upstream 3' splice site of the exon (Fu et al. 1991; Lavigueur et al. 1993; Sun et al. 1993; Watakabe et al. 1993; Caputi et al. 1994; Dirksen et al. 1994; Staknis and Reed 1994; Tanaka et al. 1994; Tian and Maniatis 1994; Ramchatesingh et al. 1995; Wang et al. 1995). Exonic enhancers are usually purine-rich sequences whose ac- ivity is  mediated, at least  in part, by a group of molecules  known as  SR (serine-  and  arginine-rich)  proteins.  These are a large  family of proteins, found  in both Drosophila and mammalian cells, each containing a serine- and arginine-rich domain and one or more RNA-binding  domains of  the  ribonucleoprotein  or RNP-type (Fu 1995; Manley and Tacke 1996; Valc~ircel and Green 1996). SR proteins have been implicated  in many aspects of the splicing process. Most notably, they have been shown to bind to exonic enhancers and in one case to synergize with more specialized regulatory proteins bound to  the  enhancer (Lynch and Maniatis
1996). Although less  understood than  exonic splicing enhancers, there are also intronic sequences that activate splicing (Balvay et al. 1992; Black 1992; Huh and Hynes 1994; Del Gatto and Breathnach 1995; Lou et al.  1995; Sirand-Pugnet et al. 1995; Carlo et al. 1996; Ryan and Cooper 1996). Intronic  splicing  enhancers  are  often found in the introns downstream of regulated exons and are required for the splicing of these exons. They have been identified in an array of transcripts, including c-src, fibronectin, ~-tropomyosin, fibroblast growth factor re-
ceptor,  cardiac  troponin  T, and  calcitonin/calcitonin gene-related peptide. These intronic  enhancers contain diverse sequence elements that are often repeated and
show a variety of tissue  specific regulation. So far,  SR proteins have not been found to bind to these sequences. Although the c-src intronic enhancer binds to a complex  of proteins, including the heterogeneous nuclear ribonucleoprotein F (hnRNP F), other proteins that  mediate splicing  through  these  regulatory  sequences  are  unknown (Min et al. 1995). ”------From :Hosung Min,  Christoph W. Turck,  Julia M. Nikolic, and Douglas L. Black ,A new regulatory protein, KSRP, mediates exon inclusion through an intronic splicing enhancer,GENES & DEVELOPMENT 1997,11:1023-1036.
8楼2013-06-25 22:28:07
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凌波丽

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感谢参与,应助指数 +1
kx444555: 金币+3, 很热心 2013-06-25 22:01:17
eiieen: 金币+5 2013-06-26 09:05:36
你的图太小,还没有上下文,我看不清楚。cryptic 应该是cryptic gene,隐蔽基因。这样我大致理解为:某个隐蔽基因的产生,通过可变剪接(alternative splicing),把不同的外显子和不同的内含子组合到一起,形成最终的外显子,这种外显子就是隐蔽基因(cryptic gene),其可能不止一种,在同一个基因位点上可能产生几种隐蔽基因(cryptic gene)。因为alternative splicing机制每次留下的外显子和去除的内含子(intron)不是固定的,而是根据需要选择一些DNA片段留下作为外显子,不是条件下的留下作为外显子(exon)的一些DNA片段在另外的条件下可能作为intron而被去除了。
箭头指向是其尾部链接的DNA片段连接的作为外显子(exon)留下的一些DNA片段,箭头的头尾连接的字母之间的其他字母是作为intron而被去除了的内含子(intron)。每个箭头表示一种alternative splicing的一种类型。

起始alternative splicing还有保留原来的部分的外显子(exon)和部分内含子(intron)的情况。但是你的图的箭头的头部落点没有对应到具体字母的应该是此类情况。
2楼2013-06-25 21:33:58
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凌波丽

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2个外显子增强子和1个内含子增强子等怎么作用的?不知道此表达的英文原文是什么?增强子是enhancer,本身是调控元件不是基因本身,谈不上外显子和内含子。
3楼2013-06-25 21:36:11
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eiieen

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引用回帖:
3楼: Originally posted by 凌波丽 at 2013-06-25 21:36:11
2个外显子增强子和1个内含子增强子等怎么作用的?不知道此表达的英文原文是什么?增强子是enhancer,本身是调控元件不是基因本身,谈不上外显子和内含子。

ISE 内含子增强子
4楼2013-06-25 21:37:19
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