Dnase1L3 Mutations Provide Novel Insight into the Catalytic Mechanism of Dnase1 Family Endonucleases

by Kristin Osika (VI)

DNA degradation is a key post-cell death process driven by the Dnase1 family of endonucleases. One such enzyme, Dnase1L3, functions primarily in the liver. While its activity is known to prevent the onset of Systemic Lupus Erythematosus (SLE), the catalytic mechanism of Dnase1L3 remains disputed. Prior research has implicated two catalytic histidines as catalytically necessary, but mutations have not been tested to date. By transforming, inducing, purifying, and conducting an activity assay, here I plan to test the impact of a proposed catalytic site mutation, H155A, on the impact of Dnase1L3 function. Assay results should illustrate that while wild type (WT) Dnase1L3 effectively degrades DNA, H155A mutants experience loss of function in vitro. Understanding Dnase1L3 catalytic site mutations contributes to a growing body of research aimed at understanding not only Dnase1L3 activity, but also the onset of SLE and other autoimmune conditions in humans.

Figure 1: A model created by Kristin Osika testing the impact of catalytic site mutation, Hr55A on the impact of Dnase1L3 function.