Jay R. Hesselberth

A novel nuclease with a possible role in nuclear pre-mRNA quality control

We are characterizing a novel mechanism in S. cerevisiae for the nuclear degradation of aberrant pre-mRNAs. Using yeast two-hybrid screens, we identified interactions between an uncharacterized protein, Ygr093w, and two components of mRNA splicing: the RNA debranching enzyme Dbr1, and the spliceosomal component Syf1. There is substantial homology between Ygr093w and the active site of Dbr1, raising the possibility that Ygr093w is a nuclease. We are carrying out studies both in vitro and in vivo to identify the substrates of this nuclease and clarify its role in the degradation of pre-mRNAs.

Genomewide detection of spliced introns

We have recently used tiling microarrays, which contain millions of overlapping oligonucleotide probes, to analyze RNA from a yeast strain carrying a genetic mutation that alters intron abundance; this analysis identified introns on a genomewide basis. This tiling array method is useful for the confirmation of predicted gene structures and the identification of novel RNA splice forms, and may be applicable to the study of alternative mRNA splicing.

Metabolite profiling

We are developing an analytical framework for the discovery of novel metabolites in yeast. By combining functional genomic methods with computational prediction and micro-scale separation methods, we identify signaling molecules used by cells in order to signify physiological states. As a first test of the framework, we are focusing on nucleotide cofactors (ATP, NAD and SAM) in order to understand their production and use as signaling molecules in a biological context (e.g. histone modification). We are also focusing on the role of lipids in cellular signaling.

My long-term focus is the development of molecular technologies for studying non-coding RNA expression and function.