Mapping of heterogeneous nuclear ribonucleoprotein (hnRNP) binding sites in regulation of alternative splicing in cancer Using a novel technique known as UV-crosslinking immunoprecipitation (CLIP), we are in the process of pinpointing the RNA sequences to which mRNA regulatory proteins bind. These small regulatory proteins, referred to as hnRNPs, control the pattern of mRNA splicing resulting in expression of alternative isoforms of proteins. In specific relevance to cancer, our laboratory has implicated the hnRNP-regulated alternative splicing of pyruvate kinase, via the metabolic pathway of aerobic glycolysis, as crucial to cancer cell proliferation. Our current efforts aim to elucidate the specific molecular targets of hnRNPs in mRNA transcripts of genes implicated in cancer