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、行为和心理上的强烈相似性表明，是我们的遗传物质在很大程度上决定了我们是什么。这种遗传物质就是我们的DNA，它可以被视为一盘非常长的‘磁带’(例如一盘巨大的录像带)，其中包含大约30亿比特的信息，编码着许多不同类型的蛋白质，这些蛋白质执行我们的大部分身体功能。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。对DNA中的这些信息进行解码的过程包括首先制作档案中其中一盘录像带的工作副本。事实上，这份初始副本中的信息是分段的，有意义的部分点缀着无意义的部分。因此，这个初始拷贝中有意义的片段需要被剪切并拼接在一起，就像电影在前电子时代通过拼接创建的一样。在许多情况下，这种剪接可以以略有不同的方式发生，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/环境中包括。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种变体。一种被称为多嘧啶结合蛋白(PTB)的蛋白质对选择性剪接产生强烈的影响，导致一些有意义的片段被包含而另一些被排除。视频拼接在一起后，被称为核糖体的小颗粒解码，核糖体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”与真实视频的相似之处在于，录像带中有图片信息的部分前面有一个没有信息的短引导者长度。在大多数情况下，我们的生物VCR(核糖体)通过快进模式搜索或扫描整个无意义的引导者，找到真正信息的起始点。然而，对于一些这样的视频，生物VCR能够直接到达有意义的图像信息开始的起始点，而无需搜索无意义的引导部分，并且在许多这样的情况下，对于生物VCR直接定位开始位置，PTB是必要的。这个项目的目的是找出PTB(A)如何使生物VCR在不需要从一开始就搜索磁带的情况下定位这些起始点，以及(B)可以影响不同有意义的片段拼接在一起以提供最终的录像带的确切模式。

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.