Molecular characterisation of leader sequences which can also mediate ribosome 'skipping'

通常一个基因编码一个蛋白质。细胞内的许多过程需要多个不同的蛋白质在每个细胞内呈现-这些蛋白质可能相互作用，或者在“途径”中依次执行特定任务。我实验室的研究一直关注的是病毒是如何用一个“基因”产生多种不同的蛋白质的。我们发现了一种方法——我们称之为“核糖体跳跃”——病毒可以通过这种方法完成这一壮举。当需要在同一细胞内表达多种不同的蛋白质时，这种方法已被证明非常适用于许多生物医学和生物技术目的。实际上，人们可以通过将多个基因与我们描述的短序列（'2A'）连接起来，将它们连接成一个。在每个2A序列中，我们设计的新蛋白质（“多蛋白”）被“切割”成其组成的单个蛋白质。幸运的是，这种方法适用于所有动物和植物细胞类型，这使得疾病的治疗、作物的遗传操作等比试图向患者引入多种基因（人类基因疗法）或在植物的情况下，例如，培育抗旱马铃薯要容易得多。我们已经发现了一种新的2A序列，它不仅可以自我切割，而且还有另一种功能，可以将蛋白质引导到细胞内的不同位置。如果序列切割，蛋白质就会位于细胞的一部分；如果它不切割，蛋白质就会进入细胞的另一部分。事实上，我们已经发现了144个新序列——但其中许多是密切相关的，所以我们不需要研究全部144个序列——只需要35个有代表性的序列。这是一个新的发现，我们想要做的一些工作将描述这个系统的生物学特征：这些不同的2As序列如何与它们具有的两种不同特性（自裂/细胞内蛋白质靶向）相关。这项工作的另一个方面是看看这些序列是否在植物和酵母中起作用。如果是这样的话，那么这些序列的潜在用途就会得到极大的扩展。我们希望开发这些序列作为其他科学家使用的工具，使他们能够研究新的疾病治疗方法，开发新的生物技术产品和工艺。

Normally one gene encodes one protein. Many processes within the cell require multiple, different, proteins to present within each individual cell - these proteins may interact with each other ,or, act sequentially (in a 'pathway' to perform a specific task. The research in my laboratory has been concerned with how viruses - with just one 'gene' - can generate multiple, different, proteins. We discovered one method - which we called 'ribosome skipping' - by which viruses can accomplish this feat. This method has proved to be very adaptable for many biomedical and biotechnological purposes when one needs to express multiple, different, proteins within the same cell. In effect, one can concatenate multiple genes into one by linking them with the short sequence ('2A') we characterised. At each 2A sequence, the new protein we have designed (a 'polyprotein') is 'cleaved' apart into it's constituent individual proteins. Fortunately, this method works in all animal and plant cell-types, which makes treatment of diseases, the genetic manipulation of crops etc. much easier than trying to introduce multiple genes into the patient (human gene therapy) or in the case of plants, for example, to make drought-resistant potatoes. We have discovered a new type of 2A sequence that can not only cleave itself, but has another function to direct the protein to a different site within the cell. If the sequence cleaves the protein becomes located in one part of the cell: if it doesn't cleave the protein goes to a different part of the cell. In fact, we have discovered 144 new sequences - but many are closely related so we don't need to study all 144 - just ~35 representative sequences. This is a new discovery and some of the work we want to do will characterise the biology of this system: how the sequence of these different 2As relates to the two different properties (self-cleaving / protein targeting within the cell) they have. The other aspect of the work is to see if these sequences work in plants and yeast. If this is so, then the potential uses of these sequences is dramatically expanded. We want to develop these sequences as tools for other scientists to use, to enable them to conduct their research into new cures for disease, for new biotechnological products and processes.