10 research outputs found
The Mre11-Nbs1 Interface Is Essential for Viability and Tumor Suppression
The Mre11 complex (Mre11, Rad50, and Nbs1) is integral to both DNA repair and ataxia telangiectasia mutated (ATM)-dependent DNA damage signaling. All three Mre11 complex components are essential for viability at the cellular and organismal levels. To delineate essential and non-essential Mre11 complex functions that are mediated by Nbs1, we used TALEN-based genome editing to derive Nbs1 mutant mice (Nbs1mid mice), which harbor mutations in the Mre11 interaction domain of Nbs1. Nbs1mid alleles that abolished interaction were incompatible with viability. Conversely, a 108-amino-acid Nbs1 fragment comprising the Mre11 interface was sufficient to rescue viability and ATM activation in cultured cells and support differentiation of hematopoietic cells in vivo. These data indicate that the essential role of Nbs1 is via its interaction with Mre11 and that most of the Nbs1 protein is dispensable for Mre11 complex functions and suggest that Mre11 and Rad50 directly activate ATM
The Mre11-Nbs1 interface is essential for viability and tumor suppression
The Mre11 complex (Mre11, Rad50, and Nbs1) is integral to both DNA repair and ataxia telangiectasia mutated (ATM)-dependent DNA damage signaling. All three Mre11 complex components are essential for viability at the cellular and organismal levels. To delineate essential and non-essential Mre11 complex functions that are mediated by Nbs1, we used TALEN-based genome editing to derive Nbs1 mutant mice (Nbs1mid mice), which harbor mutations in the Mre11 interaction domain of Nbs1. Nbs1mid alleles that abolished interaction were incompatible with viability. Conversely, a 108-amino-acid Nbs1 fragment comprising the Mre11 interface was sufficient to rescue viability and ATM activation in cultured cells and support differentiation of hematopoietic cells in vivo. These data indicate that the essential role of Nbs1 is via its interaction with Mre11 and that most of the Nbs1 protein is dispensable for Mre11 complex functions and suggest that Mre11 and Rad50 directly activate ATM
Architectural plasticity of human BRCA2-RAD51 complexes in DNA break repair
The tumor suppressor BRCA2 is a large multifunctional protein mutated in 50-60% of familial breast cancers. BRCA2 interacts with many partners and includes multiple regions with potentially disordered structure. In homology directed DNA repair BRCA2 delivers RAD51 to DNA resulting in removal of RPA and assembly of a RAD51 nucleoprotein filame
Structural dynamics of a nanomachine: investigating structure-to-function properties of large, flexible, DNA-associating proteins
Proteins, the working tools of each and every cell, are able to carry
out and catalyse all processes essential for cellular metabolism
and survival. Every protein is equipped with a set of specific
properties, e.g. catalytic or structural features, that enable them
to fulfil specific tasks necessary for the proper functioning of the
cell. Moreover, proteins and peptides can assemble in intricate,
multicomponent arrays, that further increases the efficiency and
specificity of performed tasks, thus functioning as biological
nanomachines. As in every machine, or tool, structure and
structural dynamics are inseparable with proteinâ function. With
the recent developments in techniques utilized to study protein
structure, advances in understanding protein function had been
remarkable, however, big, flexible proteins prove difficult to study
and very often remain outside the scope of conventional
biochemical investigations. The aim of this thesis was to employ
Scanning Force Microscopy (SFM) to investigate structure-to-
function relations of proteins which size and structural dynamics
are limiting factors in most biochemical approaches
Enhanced Chromatin Dynamics by FACT Promotes Transcriptional Restart after UV-Induced DNA Damage
Chromatin remodeling is tightly linked to all DNA-transacting activities. To study chromatin remodeling during DNA repair, we established quantitative fluorescence imaging methods to measure the exchange of histones in chromatin in living cells. We show that particularly H2A and H2B are evicted and replaced at an accelerated pace at sites of UV-induced DNA damage. This accelerated exchange of H2A/H2B is facilitated by SPT16, one of the two subunits of the histone chaperone FACT (facilitates chromatin transcription) but largely independent of its partner SSRP1. Interestingly, SPT16 is targeted to sites of UV light-induced DNA damage-arrested transcription and is required for efficient restart of RNA synthesis upon damage removal. Together, our data uncover an important role for chromatin dynamics at the crossroads of transcription and the UV-induced DNA damage response
Toward a pulsed antihydrogen beam for WEP tests in AEgIS
The AEgÌ
IS collaboration at CERNâs AD produces antihydrogen atoms in the form of a pulsed, isotropic source with a precisely defined formation time. AEgÌ
IS has recently undergone major upgrades to fully benefit from the increased number of colder antiprotons provided by the new ELENA decelerator and to move toward forming a horizontal beam to directly investigate the influence of gravity on the HÌ
atoms, thereby probing the Weak Equivalence Principle for antimatter. This contribution gives an overview of these upgrades as well as subsequent results from the first beam times with ELENA