MOLECULAR PATHOLOGY OF PRE-mRNS SPLICING. DIAGNOSTIC AND MECHANISTIC ASPECTS

In order for genes to exert their effects the sequence of bases in the DNA is first copied into a related molecule called pre-mRNA. A pre-mRNA molecule must be correctly processed before it can be translated in the cytoplasm of the cell. In particular, only parts of the pre-mRNA sequence are used to direct the production of specific proteins (exons) whilst the remaining parts (introns) must be removed. A process called splicing is responsible for the correct joining together of the exons. Most importantly, the exons can be selectively included by a process known as alternative splicing, allowing each pre-mRNA codify for different proteins. The result is that, although the human genome has only 25,000-35,000 genes, through the alternative splicing process the human genome can codify up to 100.000 proteins. Alternative splicing is therefore a fundamentally important mechanism that allows the production of specialized proteins in different tissues and some diseases arise when errors in alternative splicing occur. Our proposal is aimed at understanding how the splicing process is controlled. In our approach we will analyze several genes in which errors in this mechanism have already been known to cause such human genetic diseases as Cystic Fibrosis, Neurofibromatosis etc. In order to understand the molecular bases of these mistakes we will first look at how particular RNA sequences interact with regulator proteins to affect splicing. The second part of the project will then involve looking at these splicing aberrant events in a global way in order to see how the wider genomic context can influence RNA processing. The final aim of this approach will be to gather useful data for the potential development of future therapeutic and diagnostic techniques.