Alternativesplicin1--2选择性剪切..docVIP

Alternative splicing 选择性剪接 Alternative splicing produces two protein isoforms. 选择性剪接产生两种蛋白亚型。 Alternative splicing is a regulated process during gene expression that results in a single gene coding for multiple proteins. In this process, particular exons of a gene may be included within, or excluded from, the final, processed messenger RNA produced from that gene.[1] Consequently the proteins translated from alternatively spliced mRNAs will contain differences in their amino acid sequence and, often, in their biological functions (see Figure). Notably, alternative splicing allows the human genome to direct the synthesis of many more proteins than would be expected from its 20,000 protein-coding genes. Alternative splicing is sometimes termed differential splicing, but it does not increase gene expression. 选择性剪接是基因表达，其导致单基因编码多种蛋白质中一个调节的过程。在此过程中，一个基因的特定外显子可被包括，或者由排除，从该基因产生的最终，处理信使RNA[1]。因此，从选择性剪接的mRNA翻译将包含在它们的氨基酸序列和差的蛋白质，常，在它们的生物学功能（参见图）。值得注意的是，选择性剪接允许人类基因组的直接更多蛋白质的合成比将从两万蛋白质编码基因可以预期的。选择性剪接有时称为差别剪接，但它不增加基因表达。 Alternative splicing occurs as a normal phenomenon in eukaryotes, where it greatly increases the biodiversity of proteins that can be encoded by the genome;[1] in humans, ~95% of multiexonic genes are alternatively spliced.[2] There are numerous modes of alternative splicing observed, of which the most common is exon skipping. In this mode, a particular exon may be included in mRNAs under some conditions or in particular tissues, and omitted from the mRNA in others.[1] 可变剪接的发生是由于在真核生物正常现象，在那里它大大增加了可通过基因组编码的蛋白质的生物多样性;[1]在人类中，多外显子基因 ~95％的选择性剪接[2]有许多模式选择性剪接观察到的，其中最常见的是外显子跳跃。在这种模式下，特定外显子可被包括在某些条件下的mRNA或在特定组织，而在其他由mRNA被删去。[1] The production of alternatively spliced mRNAs is regulated by a system of trans-acting proteins that bind to cis-acting sites on the pre-mRNA itself. Such proteins include splicing activators that promote the usage of a particular splice site, and splicing repressors that reduce the usage of a particular site. Mechanisms of alternative splici