About Student Research

Kasandra Jean-Louise Riley (2002–2007)

Surprises from the "guardian of the genome"

While the p53 tumor suppressor protein is famous as an established barrier to the development of cancer, much remains to be understood of its biochemistry and detailed function. p53 is a transcription factor that binds double-stranded DNA. Kasandra Riley first came to Mayo as a Summer Undergraduate Research fellow from Wartburg College. Kasandra returned to undertake a Ph.D. thesis project that investigated an unexpected feature of p53: the ability of the protein to bind to RNA.

This phenomenon was encountered in the Maher lab by accident when p53 was expressed in yeast cells as a negative control for experiments performed by Ph.D. Student Laura Cassiday. Kasandra Riley pursued this puzzle and carefully investigated the p53-RNA interaction in yeast, in vitro, and in mammalian cells. Her work suggested that the basic carboxyl terminus of p53 is responsible for RNA binding, and that this interaction is not sequence specific. Moreover, Kasandra's work suggested that the normal array of post-translational modifications present at the p53 C terminus prevent RNA interactions within living cells.