TY  - JOUR
A1  - Nguyen, Tu N.
A1  - Müller, Laura S. M.
A1  - Park, Sung Hee
A1  - Siegel, T. Nicolai
A1  - Günzl, Arthur
T1  - Promoter occupancy of the basal class I transcription factor A differs strongly between active and silent VSG expression sites in Trypanosoma brucei
JF  - Nucleic Acid Research
N2  - Monoallelic expression within a gene family is found in pathogens exhibiting antigenic variation and in mammalian olfactory neurons. Trypanosoma brucei, a lethal parasite living in the human bloodstream, expresses variant surface glycoprotein (VSG) from 1 of 15 bloodstream expression sites (BESs) by virtue of a multifunctional RNA polymerase I. The active BES is transcribed in an extranucleolar compartment termed the expression site body (ESB), whereas silent BESs, located elsewhere within the nucleus, are repressed epigenetically. The regulatory mechanisms, however, are poorly understood. Here we show that two essential subunits of the basal class I transcription factor A (CITFA) predominantly occupied the promoter of the active BES relative to that of a silent BES, a phenotype that was maintained after switching BESs in situ. In these experiments, high promoter occupancy of CITFA was coupled to high levels of both promoter-proximal RNA abundance and RNA polymerase I occupancy. Accordingly, fluorescently tagged CITFA-7 was concentrated in the nucleolus and the ESB. Because a ChIP-seq analysis found that along the entire BES, CITFA-7 is specifically enriched only at the promoter, our data strongly indicate that monoallelic BES transcription is activated by a mechanism that functions at the level of transcription initiation.
KW  - RNA-polymerase-I
KW  - blood-stream forms
KW  - acrican trypanosomes
KW  - gene expression
KW  - antigenic variation
KW  - ribosomal RNA
KW  - plasmodium falciparum
KW  - virulence genes
KW  - subunit
KW  - complex
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-117232
SN  - 1362-4962
VL  - 42
IS  - 5
ER  - 
TY  - JOUR
A1  - Peissert, Stefan
A1  - Sauer, Florian
A1  - Grabarczyk, Daniel B.
A1  - Braun, Cathy
A1  - Sander, Gudrun
A1  - Poterszman, Arnaud
A1  - Egly, Jean-Marc
A1  - Kuper, Jochen
A1  - Kisker, Caroline
T1  - In TFIIH the Arch domain of XPD is mechanistically essential for transcription and DNA repair
JF  - Nature Communications
N2  - The XPD helicase is a central component of the general transcription factor TFIIH which plays major roles in transcription and nucleotide excision repair (NER). Here we present the high-resolution crystal structure of the Arch domain of XPD with its interaction partner MAT1, a central component of the CDK activating kinase complex. The analysis of the interface led to the identification of amino acid residues that are crucial for the MAT1-XPD interaction. More importantly, mutagenesis of the Arch domain revealed that these residues are essential for the regulation of (i) NER activity by either impairing XPD helicase activity or the interaction of XPD with XPG; (ii) the phosphorylation of the RNA polymerase II and RNA synthesis. Our results reveal how MAT1 shields these functionally important residues thereby providing insights into how XPD is regulated by MAT1 and defining the Arch domain as a major mechanistic player within the XPD scaffold.
KW  - nucleotide excision repair
KW  - nuclear receptors
KW  - helicase
KW  - transactivation
KW  - fluorescence
KW  - recognition
KW  - subunit
KW  - binding
KW  - sulfur
KW  - kinease
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-229857
VL  - 11
IS  - 1
ER  - 
TY  - JOUR
A1  - Rakette, Sonja
A1  - Donat, Stefanie
A1  - Ohlsen, Knut
A1  - Stehle, Thilo
T1  - Structural Analysis of Staphylococcus aureus Serine/Threonine Kinase PknB
JF  - PLoS One
N2  - Effective treatment of infections caused by the bacterium Staphylococcus aureus remains a worldwide challenge, in part due to the constant emergence of new strains that are resistant to antibiotics. The serine/threonine kinase PknB is of particular relevance to the life cycle of S. aureus as it is involved in the regulation of purine biosynthesis, autolysis, and other central metabolic processes of the bacterium. We have determined the crystal structure of the kinase domain of PknB in complex with a non-hydrolyzable analog of the substrate ATP at 3.0 angstrom resolution. Although the purified PknB kinase is active in solution, it crystallized in an inactive, autoinhibited state. Comparison with other bacterial kinases provides insights into the determinants of catalysis, interactions of PknB with ligands, and the pathway of activation.
KW  - SER/THR kinase
KW  - domain
KW  - subunit
KW  - dependent protein-kinase
KW  - mycobacterium-tuberculosis
KW  - activation mechanism
KW  - crystal structure
KW  - antibiotic resistance
KW  - catalytic
KW  - methicillin
KW  - inhibitor
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-135369
VL  - 7
IS  - 6
ER  -