Molecular Basis for the Central Role of the DEAD-Box Helicase Dhh1 in the Formation and Function of Processing Bodies

Processing-bodies (P-bodies) contain the machinery that is involved in 5ʼ
to 3ʼ mRNA degradation. This includes the DEAD box RNA helicase Dhh1 as
well as the mRNA decapping enzyme Dcp2, proteins that interact with the
decapping enzyme (Dcp1, Pat1, LSm1-7, Edc1, Edc3), the 3ʼ to 5ʼ
exonuclease Xrn1 and translationally inactive mRNA. The Dhh1 enzyme is
involved in RNP assembly, in translational repression and in the
degradation of mRNA. The hot-spot function of Dhh1 in P-body formation is
underscored by recent observations that show that the helicase undergoes
spontaneous LLPS in vitro in the presence of RNA and ATP as well as by
studies that show that the size of in vivo P-bodies is altered upon Dhh1

Here, we aim at unraveling the atomic details of the network of
intermolecular interactions between Dhh1, mRNA and other P-body
components. To that end, we make use of an in vitro bottom up approach to
assay LLPS of a mixture of purified and well defined P-body components.
These experiments are complemented with high resolution NMR studies that
identify residues that are at the center of the interaction interfaces.

Current State of Research

We have cloned and expressed most proteins and they behave well in
biochemical and biophysical experiments. This now allows us to start
mapping interactions and to perform high throughput in vitro LLPS assays

About us

Our lab is interested in combines biophysical methods (NMR spectroscopy,
X-ray crystallography and cryo-EM) with biochemical experiments
(determination of enzymatic reaction rates and LLPS diagrams). In this SPP
we are especially interested in unraveling large interaction networks in a
quantitative manner.
In particular working on the project: Julian Hübner, PhD Student

Remco Sprangers
University of Regensburg
Universitätsstrasse 31
93053 Regensburg
Phone: 0941-9437751