Detailed mapping of the sites of interaction of polypyrimidine tract binding protein with its RNA targets: viral and cellular IRESs and pre-mRNAs.

同卵双胞胎在身体、行为和心理上的高度相似性表明，正是我们的遗传物质在很大程度上决定了我们是什么样的人。这种遗传物质就是我们的DNA，它可以被看作是一个非常长的“磁带”（例如一个巨大的录像带），包含大约30亿比特的信息，编码了许多不同类型的蛋白质，这些蛋白质执行我们身体的大部分功能。DNA可以被认为是“母带”，一个由数千个正常长度的视频连接在一起的档案。在DNA中解码这些信息的过程包括首先制作档案中这些录像带之一的工作副本。事实上，这个初始副本中的信息是分段的，有意义的部分散布在无意义的部分中。因此，最初拷贝中有意义的片段需要剪切并拼接在一起，就像在电子时代之前通过拼接来制作电影一样。在许多情况下，这种剪接可以以稍微不同的方式发生，其中一些有意义的片段在某些细胞或某些情况下被排除，但在其他细胞/情况下被包括。因此，存档的“视频”的初始副本可以产生最终可播放视频的多于一个变体。一种被称为多聚嘧啶束结合蛋白（PTB）的蛋白质对选择性剪接产生强烈影响，导致一些有意义的片段被包含而另一些片段被排除。在视频被拼接在一起之后，它被称为核糖体的小颗粒解码，它基本上执行类似于录像机（VCR）的功能，因为它将信息解码为图片。“生物视频”与真实的视频类似，因为具有图像信息的磁带部分之前是没有信息的短前导长度。在大多数情况下，我们的生物VCR（核糖体）通过快速搜索或扫描整个无意义的领导者来找到真正信息的起点。然而，对于某些这样的视频，生物VCR能够直接进入有意义的图像信息开始的起始点，而不需要搜索无意义的前导部分，并且在许多这样的情况下，PTB对于生物VCR的起始位置的直接定位是必要的。这个项目的目的是找出PT B如何（a）使生物VCR定位这些起始位点，而不需要从一开始就搜索整个磁带，以及（B）如何影响不同有意义的片段拼接在一起的确切模式，从而得到最终的录像带。

The strong physical, behavioural, and mental similarity of identical twins shows that it is our genetic material that largely specifies what we are. This genetic material is our DNA, which can be regarded as an exceedingly long 'tape' (e.g. an enormous video tape) with some 3 billion bits of information, coding for the numerous different types of protein which carry out most of our bodily functions. The DNA can be thought of as the 'master tape', an archive of thousands of normal length videos joined together. The process of decoding this information in the DNA involves first making a working copy of one of these videotapes in the archive. In fact the information in this initial copy is segmented, with the meaningful segments interspersed with meaningless sections. Consequently, the meaningful segments in this initial copy need to be cut out and spliced together, much as cine films were created by splicing in the pre-electronic era. In many cases, this splicing can occur in slightly different ways, with some meaningful segments excluded in some cells or some circumstances, but included in other cells/circumstances. Thus the initial copy of the archived 'video' can give rise to more than one variant of the final playable video. A protein known as polypyrimidine tract binding protein (PTB) exerts a strong influence on the alternative splicing, causing the inclusion of some meaningful segments and the exclusion of others. After the video has been spliced together it is decoded by a small particle known as a ribosome, which essentially carries out an analogous function to that of a video recorder (VCR) as it decodes the information as pictures. The 'biological videos' are similar to real videos in so far as the part of the tape with the pictorial information is preceded by a short leader length that has no information. In most cases our biological VCR (the ribosome) finds the point where the true information starts by searching or scanning in fast-forward mode through the whole meaningless leader. However, with some such videos the biological VCR is able to go straight to the starting point where the meaningful pictorial information begins without searching through the meaningless leader section, and in many such cases PTB is necessary for the direct location of the start position by the biological VCR. The aim of this project is to find out how PTB (a) causes the biological VCR to locate these starting sites without a need for searching through the tape from the very start, and (b) can influence the exact pattern in which the different meaningful segments are spliced together to give the finished video tape.