Regulation of protein multi-functionality by 3 UTRs

3‘端非编码区对蛋白质多功能的调控 摘要 许多蛋白质功能是由蛋白质复合体介导的，而蛋白质复合体的形成往往受丰度的调节 随着更高的级别增加了遇到互动伙伴的机会。MRNA包含一个编码区，该编码区 被翻译成蛋白质，但它们也包含一个3‘非翻译区(3’UTR)。除了通过以下方式进行监管 丰富，我的实验室发现，蛋白质的功能可以由3‘UTRs调节，就像在蛋白质合成过程中一样 3‘端非编码区参与蛋白质间的相互作用。3‘端非编码区依赖的蛋白质复合体组装是由 本地翻译环境。每个mRNA生成自己的翻译环境，该环境由 与该信使核糖核酸结合的蛋白质和招募的蛋白质。因此，mrna的异构体具有选择性。 通常长度差异很大的3‘UTRs提供了截然不同的翻译环境，以及 因此编码不同的蛋白质功能。目前，数以千计的3‘非编码区依赖功能是未知的 因为它们不能从典型的蛋白质功能中推断出来。我们已经开发出一种方法来 系统鉴定多个非编码区基因的长3‘非编码区亚型介导的蛋白质功能 基于CRISPR的方法。我们将鉴定3‘UTRs，它们调节目前为止未知的蛋白质功能。 在迁移和分化的调节中，逃避细胞死亡。 我们目前知道两种实现3‘非编码区依赖功能的方法。如上所述，一种可以 包含一个长3‘的UTR，可以生成自己的翻译环境。此外，mRNAs可以在 他们的3‘UTRs定位于由相分离的胞质形成的预先存在的翻译环境 车厢。在这些大的细胞质无膜细胞器中，环境是由许多 MRNAs及其招募的蛋白质。我们发现了这样一个称为TIS颗粒网络的隔室。 我们测定了数百个浓缩的mRNA，并观察到通常只有一半的转录本具有相同的 3‘非编码区定位于TIS颗粒。这意味着蛋白质可以有不同的功能，这取决于 它们在胞浆或TIS颗粒中被翻译。我们的目标是研究蛋白质如何改变它们的 在TIS颗粒内转换时的函数。为了研究TIS颗粒依赖的蛋白质功能，我们有 不能组装TIS颗粒的工程化细胞。对于其mRNAs强烈的候选人 富含TIS颗粒，我们正在研究TIS颗粒中的翻译是否控制后- 翻译修饰，特定蛋白质复合体的建立，或者它是否抑制蛋白质 聚合。 如果成功，我们的研究将揭示信使核糖核酸在脑区隔和生理功能中的广泛作用。 翻译中的脚手架。它将展示3‘UTRs中的元素如何对蛋白质的多样化做出贡献 功能。从长远来看，它将促进mrna疗法的发展，其中包括特定的 3‘非编码区元件允许mRNAs编码具有更强大或替代功能的蛋白质。

Regulation of protein multi-functionality by 3′UTRs SUMMARY Many protein functions are mediated by protein complexes whose formation is often regulated by abundance as higher levels increase the chance to encounter an interaction partner. mRNAs contain a coding region that is translated into protein, but they also contain a 3′ untranslated region (3′UTR). In addition to regulation by abundance, my lab discovered that protein function can be regulated by 3′UTRs as during protein synthesis 3′UTRs mediate protein-protein interactions. 3′UTR-dependent protein complex assembly is mediated by the local translation environment. Each mRNA generates its own translation environment that consists of the proteins bound by the mRNA together with the recruited proteins. As a result, mRNA isoforms with alternative 3′UTRs – that often differ substantially in length – provide drastically different translation environments, and thus encode different protein functions. Currently, thousands of 3′UTR-dependent functions are unknown because they cannot be inferred from canonical protein functions. We have developed a method to systematically identify protein functions mediated by long 3′UTR isoforms of multi-UTR genes using a CRISPR-based approach. We will identify 3′UTRs that mediate so far unknown protein functions involved in the evasion of cell death, in the regulation of migration, and differentiation. We currently know of two ways to achieve 3′UTR-dependent functions. As described above, an mRNA that contains a long 3′UTR can generate its own translation environment. Moreover, mRNAs can use elements in their 3′UTRs to localize to pre-existing translation environments that are formed by phase-separated cytosolic compartments. Within these large cytosolic membraneless organelles the environment is generated by many mRNAs together with their recruited proteins. We discovered such a compartment called TIS granule network. We determined hundreds of enriched mRNAs and observed that usually only half of transcripts with the same 3′UTR localize to TIS granules. This implies that proteins can have alternative functions depending on whether they are translated in the cytosol or in TIS granules. Our goal is to investigate how proteins change their function when translated within TIS granules. To study TIS granule-dependent protein functions, we have engineered cells that are unable to assemble TIS granules. For candidates whose mRNAs are strongly enriched in TIS granules, we are investigating if translation in TIS granules controls the addition of post- translational modifications, the establishment of specific protein complexes, or if it suppresses protein aggregation. If successful, our research will reveal a widespread role of mRNA in the compartmentalization and physical scaffolding during translation. It will show how elements in 3′UTRs contribute to the diversification of protein function. In the long-term, it will facilitate the development of mRNA therapeutics where inclusion of specific 3′UTR elements allows mRNAs to encode proteins with more robust or alternative functions.