Post-transcriptional regulation of TNF-alpha production

性状（申请人提供）：一种富含腺嘌呤和尿苷的元素（ARE） 位于TNF α转录物的3'非翻译区调节mRNA 稳定性和翻译的方式，防止TNF α的过度表达。 ARE依赖的转录后调控需要RNA结合活性 作为翻译阻遏物发挥功能的蛋白质（例如TIA-1和TIAR）， 稳定剂（例如HuR）和mRNA去稳定剂（例如AUF 1和TTP）。人惊讶 关于这些ARE结合蛋白（ARE-BPs）如何相互作用， 调节TNFa的表达。TIA-I（和/或TIAR）促进一般的免疫应答。 翻译抑制，伴随着环境压力和 TNF α的选择性翻译抑制发生在LPS激活的 巨噬细胞翻译抑制的转录本在 离散的细胞质病灶，称为应激颗粒（SG）。我们假设 SG作为翻译检查点起作用， 转录本被翻译或降解。我们进一步建议， 受调节转录物稳定性的ARE-BP（例如HuR、AUF 1和 TTP）。我们将通过确定以下来测试这些假设：i）TIA-1的作用 截短突变体，其抑制SG的组装对TNF α的产生， ii）巨噬细胞中LPS诱导的SG的mRNA和蛋白质组成， 不同功能类别的ARE-BP是否以不同的方式与TNFa ARE结合， 合作、非合作或竞争的方式，以及iv）如何不同 ARE-Bps的功能类别协同调节TNF α的产生。 这些目标的完成将提高我们对ARE-BP如何相互作用的理解 调节TNFa的产生。这些研究也可能确定分子 开发可使用的口服TNFa阻滞剂的目标 来治疗风湿性关节炎的病人。

DESCRIPTION (provided by applicant): An adenine and uridine-rich element (ARE) located in the 3' untranslated region of TNF a transcripts regulates mRNA stability and translation in a way that prevents the overexpression of TNFa. ARE-dependent post-transcriptional control requires the activity of RNA-binding proteins that function as translational repressors (e.g. TIA-l and TIAR), rnRNA stabilizers (e.g. HuR) and mRNA destabilizers (e.g. AUF1 and TTP). Surprisingly little is known about how these ARE-binding proteins (ARE-BPs) interact to regulate the expression of TNFa. TIA-l (and/or TIAR) promote the general translational repression that accompanies environmental stress and the selective translational repression of TNFa that occurs in LPS-activated macrophages. Translationally repressed transcripts transiently accumulate at discrete cytoplasmic foci known as stress granules (SGs). We hypothesize that the SG functions as a translational checkpoint that determines whether TNFa transcripts are translated or degraded. We further propose that this decision is influenced by ARE-BPs that regulate transcript stability (e.g. HuR, AUF1 and TTP). We will test these hypotheses by determining: i) the effect of a TIA-l truncation mutant that inhibits the assembly of SGs on the production of TNFa, ii) the mRNA and protein composition of LPS-induced SGs in macrophages, iii) whether different functional classes of ARE-BPs bind to the TNFa ARE in a cooperative, non-cooperative or competitive manner, and iv) how different functional classes of ARE-Bps cooperate to regulate the production of TNFa. Completion of these aims will improve our understanding of how ARE-BPs interact to regulate the production of TNFa. These studies might also identify molecular targets for the development of orally available TNFa blockers that can be used to treat patients with rheumatoid arthritis.