P120 Specific domain knockout of murine DNA damage

P120
Specific domain knockout of murine DNA damage-inducible protein 2 (Ddi2)
Svoboda Michal, Kašpárek Petr, Chawengsaksophak Kallayanee, Procházka Jan, Sedláček
Radislav, Konvalinka Jan, Grantz Šašková Klára, Sivá Monika
Přírodovědecká Fakulta Univerzity Karlovy v Praze; ÚOCHB AV ČR,v.v.i.
E-mail: [email protected]
Sekce: Molekulární genetika v biochemii a medicíně
Ddi1-like proteins are considered to belong to a family of protein shuttles, such as Rad23 and
Dsk2, that are responsible for regulation of protein degradation in ubiquitin-proteasome
system. The function of shuttling proteins is provided via conserved domains – ubiquitin-like
domain (UBL) targeting the proteasome, and ubiquitin-associated domain (UBA) bound to
the polyubiquitin chain on the substrate. In contrast to other family members, Ddi1-like
proteins harbor a retroviral protease-like domain (RVP), structurally similar to HIV protease,
which contains a catalytic triad DT/SG typical for aspartic proteases. This suggests an
additional role which has not been sufficiently studied yet.
Ddi1-like proteins are highly conserved among eukaryotes and have an important role, as
knockout experiments in yeast, worms and fruit flies suggest. In S. cerevisiae, the deficiency
of DDI1 gene results in increased secretion of various proteins into growth media. Knockouts
of Ddi1 in C. elegans and in D. melanogaster cause defects in synaptogenesis and germline
cell development, respectively.
Our study focuses on revealing the biological role of mammalian homolog of Ddi1-like
proteins, DNA damage-inducible protein 2 (Ddi2), using gene knockout in mouse. As the
human gene shares 96% sequence identity with its murine ortholog, mouse represents an ideal
model for studying its function. We successfully generated mice with defect in the Ddi2 gene
that results in embryonic lethality of homozygous individuals. The truncation of the protein in
the RVP domain causes severe developmental defects in embryo, yolk sac and early placenta.