Binding site density enables paralog-specific activity of SLM2 and Sam68 proteins in Neurexin2 AS4 splicing control.
Binding site density enables paralog-specific activity of SLM2 and Sam68 proteins in Neurexin2 AS4 splicing control.
复制标题
DOI：
10.1093/nar/gkw1277
复制
发表时间：
2017-04-20
影响因子：
14.9
通讯作者：
Elliott DJ
中科院分区：
文献类型：
--
作者：
Danilenko M;Dalgliesh C;Pagliarini V;Naro C;Ehrmann I;Feracci M;Kheirollahi-Chadegani M;Tyson-Capper A;Clowry GJ;Fort P;Dominguez C;Sette C;Elliott DJ
SLM 2和Sam 68是剪接调节子旁系同源物，通常在功能上重叠，但只有SLM 2而不是Sam 68控制对脑功能重要的Neurexin 2 AS 4外显子。在此，我们发现，SLM 2和Sam 68类似地结合到Neurexin 2前mRNA，无论是在小鼠皮质内还是在体外。蛋白质结构域交换实验鉴定了包括区分SLM 2和Sam 68在剪接靶选择中的活性的星星结构域的区域，并证实这不是通过参与RNA接触的变体氨基酸建立的。然而，与在Sam 68和SLM 2共同控制下的Neurexin 1和Neurexin 3 AS 4外显子侧翼的那些相比，更少的SLM 2和Sam 68 RNA结合位点侧翼Neurexin 2 AS 4外显子。通过将Neurexin 2 AS 4外显子置于Sam 68和SLM 2的联合剪接控制下，加倍结合位点数切换了Parkinson敏感性。我们的数据支持一个模型，其中靶外显子周围的共享RNA结合位点的密度，而不是不同的旁系同源特异性蛋白-RNA结合位点，控制SLM 2和Sam 68之间的Neurexin 2 AS 4外显子的功能性靶特异性。类似的模型可以解释不同的控制由其他剪接调节家族内的旁系同源物与不可区分的RNA结合位点。
SLM2 and Sam68 are splicing regulator paralogs that usually overlap in function, yet only SLM2 and not Sam68 controls the Neurexin2 AS4 exon important for brain function. Herein we find that SLM2 and Sam68 similarly bind to Neurexin2 pre-mRNA, both within the mouse cortex and in vitro. Protein domain-swap experiments identify a region including the STAR domain that differentiates SLM2 and Sam68 activity in splicing target selection, and confirm that this is not established via the variant amino acids involved in RNA contact. However, far fewer SLM2 and Sam68 RNA binding sites flank the Neurexin2 AS4 exon, compared with those flanking the Neurexin1 and Neurexin3 AS4 exons under joint control by both Sam68 and SLM2. Doubling binding site numbers switched paralog sensitivity, by placing the Neurexin2 AS4 exon under joint splicing control by both Sam68 and SLM2. Our data support a model where the density of shared RNA binding sites around a target exon, rather than different paralog-specific protein–RNA binding sites, controls functional target specificity between SLM2 and Sam68 on the Neurexin2 AS4 exon. Similar models might explain differential control by other splicing regulators within families of paralogs with indistinguishable RNA binding sites.