Mechanisms of Translation Initiation Mediated by mRNA Structure

mRNA结构介导的翻译起始机制 分子生物学的中心法则是DNA用于制造mRNA，mRNA用于制造蛋白质。 翻译的起始，即从信使RNA（mRNA）中产生蛋白质的行为，是蛋白质翻译的核心。 规范这个过程。翻译起始的失调在许多人类细胞中起着重要的作用。 包括癌症在内的疾病。在包括人类在内的真核生物中，翻译的起始涉及募集 与mRNA的两个末端（5'和3'）相互作用的因子，本质上是一个圆圈， 被翻译。因子的募集和随后的循环化功能知之甚少。 我们的目标是通过核酸的物理化学的透镜来对这个生物学问题进行新的观察 和结构生物学。虽然因子介导的mRNA环化被认为是蛋白质合成的关键， 综合，这一建议提出了另一种假设：形成碱基配对的相互作用内的 mRNA本身导致在不存在蛋白质复合物的情况下mRNA的环化。所以 mRNA的末端固有地彼此靠近。这种“循环化”可以促进 补充蛋白质复合物，从而帮助翻译起始。为了验证我们的假设，我们将 通过实验研究在没有蛋白质起始的情况下mRNA的末端是否紧密接近 配合物我们还将测试mRNA末端之间的碱基配对相互作用的破坏是否抑制了 蛋白质合成和翻译起始因子与mRNA的结合。拟议的研究将跨越一个 包括单分子荧光显微术和荧光光谱学的方法谱， RNA结构的化学探测、计算生物学和体内翻译的检查。我们提出的 研究将阐明mRNA二级结构和末端到末端距离是否是 在真核生物中控制翻译起始。

Mechanisms of Translation Initiation Mediated by mRNA Structure The Central Dogma of molecular biology is that DNA is used to make mRNA, which is used to make proteins. The initiation of translation, the act of making proteins from messenger RNA (mRNA), is central to the regulation of this process. Dysregulation of translation initiation plays an important role in a number of human diseases including cancer. In eukaryotes including humans, the initiation of translation involves the recruitment of factors that interact with the two (5' and 3') ends of the mRNA to make, in essence, a circle that is poised to be translated. The recruitment of factors and the function of subsequent circularization are poorly understood. We aim to take a novel look at this biological problem through the lens of physical chemistry of nucleic acids and structural biology. Although factor-mediated circularization of mRNA is thought to be critical for protein synthesis, this proposal puts forward an alternative hypothesis: formation of basepairing interactions within the mRNA itself results in the circularization of the mRNA in the absence of the protein complexes. Hence, the ends of the mRNA are inherently located close to one another. Such “circularization” could facilitate the recruitment of the protein complexes and thereby aid translation initiation. To test our hypothesis, we will experimentally examine whether the ends of mRNAs are in close proximity in the absence of protein initiation complexes. We will also test whether the disruption of basepairing interactions between mRNA ends inhibits protein synthesis and binding of translation initiation factors to the mRNA. The proposed studies will span a spectrum of approaches including single-molecule fluorescent microscopy and fluorescent spectroscopy, chemical probing of RNA structure, computational biology and examination of translation in vivo. Our proposed studies will elucidate whether mRNA secondary structure and end-to-end distance are major determinants that govern translational initiation in eukaryotes.