Mechanisms of Translation Initiation Mediated by mRNA Structure

信使核糖核酸结构介导的翻译启动机制 分子生物学的中心法则是DNA被用来制造信使核糖核酸，信使核糖核酸被用来制造蛋白质。 翻译的启动，即从信使RNA(信使RNA)制造蛋白质的行为，是 对这一过程的监管。翻译启动的失调在许多人类中扮演着重要的角色 包括癌症在内的疾病。在包括人类在内的真核生物中，翻译的启动涉及招募 与信使核糖核酸的两个末端(5‘和3’)相互作用的因子，在本质上，形成一个稳定的循环 被翻译。对因子的募集和随后的循环功能知之甚少。 我们的目标是通过核酸物理化学的透镜，以一种新的方式看待这个生物问题 和结构生物学。尽管因子介导的信使核糖核酸的循环被认为是蛋白质的关键 综上所述，这一建议提出了另一种假设：在 在没有蛋白质复合体的情况下，信使核糖核酸本身导致信使核糖核酸的环化。因此， 该信使核糖核酸的末端天生地彼此靠近。这种“循环化”可以促进 蛋白质复合体的招募，从而有助于翻译的启动。为了检验我们的假设，我们将 在没有蛋白质起始的情况下，通过实验检查mRNAs的末端是否非常接近 复合体。我们还将测试mRNA末端之间碱基配对相互作用的中断是否会抑制 蛋白质合成和翻译起始因子与信使核糖核酸的结合。拟议的研究将跨越一个 包括单分子荧光显微镜和荧光光谱在内的各种方法， RNA结构的化学探测、计算生物学和体内翻译检查。我们的建议 研究将阐明mRNA二级结构和末端到末端的距离是否是决定 管理真核生物中的翻译启动。

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.