Regulation of mRNA processing: Mechanisms and Consequences

真核生物mRNAs的合成是一个复杂的过程，包括mRNAs的剪接和3‘端的形成 先驱物。我的实验室多年来一直在研究这些过程，包括最近它们如何在 辨证与疾病。这一建议继续了我们对这些主题的研究，并可分为 以下是几个方面。癌症中的信使核糖核酸加工。研究编码剪接的基因突变如何 导致MDS和其他肿瘤的因素将继续存在，重点是SF3B1。研究以澄清 SF3B1突变影响剪接的机制(S)以及 不规范和导致疾病将被追查。关于机制，近期目标将是 继续表征SUGP1的SF3B1相互作用区。另一个目标是确定SUGP1- 与RNA解旋酶相互作用，并确定其在正常BP识别中的功能，这将使 确定SF3B1突变破坏剪接的详细机制。关于路径， 阐明最近描述的MAP3K7/p38/GATA1通路细节的实验 对MDS患者进行贫血检查。影响其他相关通路的错误拼接事件，如异常 将对核因子-kB的激活进行研究。FUS和其他限制性商业惯例在ALS/FTD中。关于FUS，实验是为了 分析FUS核质内稳态，这是形成有毒细胞质FUS的重要过程 聚合，将继续。支持涉及NPC和相互作用的门控机制的证据 对于本身与肌萎缩侧索硬化症(ALS)有关的特定核孔素，将继续进行研究。建议这一过程可能 涉及细胞类型特异性，MNS可能更具允许性，将进行调查。实验 观察到RBP聚集和随之而来的错接发生在很大一部分零星的 ALS/FTD患者的大脑在没有已知突变的情况下将继续存在。聚合体将从 运动皮质样本和蛋白质/RNA组成被确定为研究可能导致其成核的因素 队形。AS对PA因子活性的调节作用。细胞外基质异构体功能的研究 将继续研究多聚腺苷(PA)因子WDR33。内含子产生两种短的异构体v2和v3。 V2，而不是v3，是一种不直接参与PA的核内膜蛋白。相互作用的蛋白质 两者都将被确认，并将继续追查表明它们被核因子-kB途径上调的结果。 这两种异构体在包括SARS-CoV-2感染在内的抗病毒反应中发挥作用的证据将是 进一步调查。在人类体内产生45种PA因子Fip1亚型的发现将是 探索过了。ERNAs作为mRNAs。结果表明，某些核不稳定的lncRNA，包括eRNAs，是 稳定的，输出到细胞质的，在某些情况下被翻译的，将被追求。观察到高达5% 当外体辅因子MTR4耗尽时，含有重要的ORF和可能被翻译的eRNAs的将是 进一步调查。Erna“激活”的可能生理意义将在#年进行研究。 分化的hESCs，显示其mtr4水平显著降低。

Synthesis of eukaryotic mRNAs is a complex process, and includes splicing and 3’ end formation of mRNA precursors. My lab has studied these processes for many years, including recently how they function in differentiation and disease. This proposal continues our studies on these topics, and can be divided into the following areas. mRNA processing in cancer. Work investigating how mutations in genes encoding splicing factors lead to MDS and other neoplasms will be continued, with an emphasis on SF3B1. Studies to elucidate both the mechanism(s) by which SF3B1 mutations affect splicing as well as the pathways that are dysregulated and lead to disease will be pursued. With respect to mechanism, an immediate goal will be to continue characterizing the SF3B1-interacting region of SUGP1. Another goal is to identify the SUGP1- interacting RNA helicase and determine its function in normal BP recognition, which will then allow determination of the detailed mechanism by which SF3B1 mutations disrupt splicing. With respect to pathways, experiments to elucidate the details of the recently described MAP3K7/p38/GATA1 pathway that underlies anemia in MDS will be performed. Missplicing events that affect other relevant pathways, such as aberrant activation of NF-kB, will be studied. FUS and other RBPs in ALS/FTD. With respect to FUS, experiments to analyze FUS nucleocytoplasmic homeostasis, a process important for formation of toxic cytoplasmic FUS aggregates, will be continued. Evidence supporting a gating mechanism involving the NPC and interactions with specific nucleoporins, themselves implicated in amyotrophic lateral sclerosis (ALS), will be pursued. Suggestions that this process may involve cell-type specificity, with MNs perhaps being more permissive, will be investigated. Experiments pursing the observation that RBP aggregates and consequent missplicing occur in a large fraction of sporadic ALS/FTD patient brains in the absence of known mutations will be continued. Aggregates will be isolated from motor cortex samples and protein/RNA composition determined to investigate what might nucleate their formation. Regulation of PA factor activity by AS. Experiments investigating the functions of isoforms of the polyadenylation (PA) factor WDR33 will be pursued. Two short isoforms, v2 and v3, are produced by intronic PA), and v2 but not v3 is an inner nuclear membrane protein not directly involved in PA. Interacting proteins of both will be identified, and results suggesting they are upregulated by an NF-kB pathway will be pursued. Evidence that the two isoforms function in the antiviral response, including to SARS-CoV-2 infection, will be further investigated. The finding that 45 isoforms of the PA factor Fip1 are produced in humans will be explored. eRNAs as mRNAs. Results suggesting that certain nuclear unstable lncRNAs, including eRNAs, are stabilized, exported to the cytoplasm and in some case translated, will be pursued. Observations that up to 5% of eRNAs contain significant ORFs and may be translated when the exosome cofactor Mtr4 is depleted will be further investigated. The possible physiological significance of eRNA “activation” will be studied in differentiated hESCs, which were shown to have sharply reduced levels of Mtr4.