Research objectives and content
The human nuclear cap binding complex (CBC) plays a role in different aspects of RNA metabolism. CBC facilitates removal of cap proximal introns, increases the efficiency of 3' end cleavage, ensures poly (A) tail length control and is involved in the transport of snRNAs to the cytoplasm. A yeast CBC (yCBC) has recently been isolated. This yeast homologue is capable of cap binding, is a commitment complex component involved in an early step of pre-mRNA splicing and can interact in vivo with the protein import machinery. We propose to analyze the involvement of yCBC in RNA transport and 3' end processing and to study the molecular mechanisms that allow yCBC to influence RNA metabolism. A synthetic lethal screen using yCBC has already been carried out and 32 positive mutant lines have been isolated. The genes mutated in these yeast strains are expected to encode products that functionally interact with CBC. Some of these clones show reduced splicing efficiency or nuclear poly (A) accumulation. We propose to isolate the genes responsible for these phenotypes and study their function. Once a function related to RNA metabolism is observed, the functional interaction with CBC will be analyzed.
Training content (objective, benefit and expected impact)
The isolation of factors involved in cap dependent RNA metabolism will allow us to understand better the molecular mechanisms of RNA processing and transport as well as the function of the RNA cap in these processes. This understanding will be of potential usefulness in designing vectors that are capable of high level expression of heterologous genes in the biotechnology and basic research fields.