Heterogeneous nuclear ribonucleoprotein roles in alternative RNA splicing and human disease (2007–2010)
Control of the use of DNA, gene expression, is vital to all living organisms, especially in development and disease. The information in the genes of DNA is transferred to an intermediate molecule, mRNA, in a process called transcription. The genetic information in the mRNA is subsequently used, in the process called translation, to make the protein encoded by the original gene. The switching on and off of DNA appears to be most frequently controlled at the transcription step but recently it has become apparent that there are many post-transcriptional events that govern how efficiently the genetic information is ultimately converted to protein molecules. An important step is the cutting out of parts (introns) of the RNA molecule that is copied from DNA, and splicing of the retained sections (exons). During this process the RNA may also lose one or more of its exons. As a result of this variable retention of exons a single gene may produce many isoforms of the protein it encodes. By this mechanism the roughly 30,000 genes in the human genome can give rise to potentially hundreds of thousands of proteins. RNA splicing connects to cancer in two ways. First, changes in the concentrations of the proteins that control splicing may change the isoforms, resulting in changes that lead to uncontrolled cell proliferation. Secondly, DNA mutations that affect the splicing process can also vary the ratios of the isoforms produced from a gene: if this occurs in a protein that is involved in the growth of cells this too may lead to cancer. In this project we will study the molecular mechanism of this alternative splicing, and particularly a group of proteins that generally favour the excision of some exons, with a focus on cancer cells. Recent publications have highlighted the potential for the therapeutic use of drugs that target the splicing apparatus: it is anticipated that studies of alternative splicing will underpin development of new therapeutic agents.