Talk abstracts

Talk on Saturday 08:45-09:00am submitted by Kim Delaney

Evolution of Ancestral URB Protein Toward Modern U1A/U2´´ snRNP proteins.

Kimberly J. Delaney (Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine), Sandra G. Williams (Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine), Mariah Lawler (Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine), Kathleen B. Hall (Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine)

Abstract:
The U1A/U2B´´/SNF family of snRNP proteins has been highly conserved, as indicated by the 70% homology between their first (and RNA binding) RRMs. However, despite their high degree of sequence similarity, each exhibits unique RNA binding properties. Previously, in an effort to understand the evolutionary pressures that have lead to this functional divergence, we reconstructed the protein phylogeny and discovered that the last common ancestor between humans (U1A & U2B´´) and Drosophila (SNF) contained a single ancestral protein (URB). We have gone on to further examine the reconstructed phylogenetic tree to investigate the changes that occurred as the proteins evolved toward the modern vertebrate specimens. Specifically, the predecessors of modern U1A and U2B´´resulted from a gene duplication in ancestors of jawed vertebrates. We have constructed proteins along the lineage from URB to U1A/U2B´´ and investigated their RNA binding affinity and specificity. Using modern U1 snRNA Stemloop II and U2 snRNA Stemloop IV, and selected mutations, we are mapping the path of protein changes that lead to specific RRM recognition. Supported by NIH R01 GM096444 to KBH, F31 GM089576 to SGW.

References:
Williams and Hall (2013) JMB E-pub ahead of print.

Keywords: snRNP, RRM, evolution