Publications by authors named "Jan Palecek"

Structural maintenance of chromosome (SMC) complexes play roles in cohesion, condensation, replication, transcription, and DNA repair. Their cores are composed of SMC proteins with a unique structure consisting of an ATPase head, long arm, and hinge. SMC complexes form long rod-like structures, which can change to ring-like and elbow-bent conformations upon binding ATP, DNA, and other regulatory factors.

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DNA-protein crosslinks (DPCs) are highly toxic DNA lesions represented by proteins covalently bound to the DNA. Persisting DPCs interfere with fundamental genetic processes such as DNA replication and transcription. Cytidine analog zebularine (ZEB) has been shown to crosslink DNA METHYLTRANSFERASE1 (MET1).

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Most eukaryotic organisms employ a telomerase complex for the maintenance of chromosome ends. The core of this complex is composed of telomerase reverse transcriptase (TERT) and telomerase RNA (TR) subunits. The TERT reverse transcriptase (RT) domain synthesises telomeric DNA using the TR template sequence.

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Structural maintenance of chromosomes (SMC) complexes are molecular machines ensuring chromatin organization at higher levels. They play direct roles in cohesion, condensation, replication, transcription, and DNA repair. Their cores are composed of long-armed SMC, kleisin, and kleisin-associated subunits.

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Telomere repeat binding proteins (TRBs) belong to a family of proteins possessing a Myb-like domain which binds to telomeric repeats. Three members of this family (TRB1, TRB2, TRB3) from Arabidopsis thaliana have already been described as associated with terminal telomeric repeats (telomeres) or short interstitial telomeric repeats in gene promoters (telo-boxes). They are also known to interact with several protein complexes: telomerase, Polycomb repressive complex 2 (PRC2) E(z) subunits and the PEAT complex (PWOs-EPCRs-ARIDs-TRBs).

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The integrity of plant genetic information is constantly challenged by various internal and external factors. Therefore, plants use a sophisticated molecular network to identify, signal and repair damaged DNA. Here, we report on the identification and analysis of four uncharacterized Arabidopsis BRCT5 DOMAIN CONTAINING PROTEINs (BCPs).

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Background: Inconsistencies in the management of hypothyroidism have been reported among endocrinologists in different European countries. Aim of this study was to explore Czech endocrinologists' use of thyroid hormones in hypothyroid and euthyroid patients.

Methods: We used a web-based survey containing 32 questions regarding the use of thyroid hormones.

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Objective: Thyroid nodules are a common finding in the general population. The primary aim of the study was to determine the prevalence of thyroid nodules and cancer found by ultrasound (US) in women who underwent screening for thyroid dysfunction during pregnancy.

Design: A double-centric, retrospective, cohort study.

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Structural Maintenance of Chromosomes (SMC) complexes are important for many aspects of the chromosomal organization. Unlike cohesin and condensin, the SMC5/6 complex contains a variant RING domain carried by its Nse1 subunit. RING domains are characteristic for ubiquitin ligases, and human NSE1 has been shown to possess ubiquitin-ligase activity in vitro.

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The SMC (Structural Maintenance of Chromosomes) complexes are composed of SMC dimers, kleisin and kleisin-interacting (HAWK or KITE) subunits. Mutual interactions of these subunits constitute the basal architecture of the SMC complexes. In addition, binding of ATP molecules to the SMC subunits and their hydrolysis drive dynamics of these complexes.

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Networks of protein-protein interactions (PPI) constitute either stable or transient complexes in every cell. Most of the cellular complexes keep their function, and therefore stay similar, during evolution. The evolutionary constraints preserve most cellular functions via preservation of protein structures and interactions.

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Analysis of protein-protein interactions (PPI) is key for the understanding of most protein assemblies including structural maintenance of chromosomes (SMC) complexes. SMC complexes are composed of SMC proteins, kleisin, and kleisin-interacting subunits. These subunits interact in specific ways to constitute and regulate the closed structure of the complexes.

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Mdm2 and MdmX are related proteins serving in the form of the Mdm2 homodimer or Mdm2/MdmX heterodimer as an E3 ubiquitin ligase for the tumor suppressor p53. The dimerization is required for the E3 activity and is mediated by the conserved RING domains present in both proteins, but only the RING domain of Mdm2 can form homodimers efficiently. We performed a systematic mutational analysis of human Mdm2, exchanging parts of the RING with the corresponding MdmX sequence, to identify the molecular determinants of this difference.

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The genome replication process is challenged at many levels. Replication must proceed through different problematic sites and obstacles, some of which can pause or even reverse the replication fork (RF). In addition, replication of DNA within chromosomes must deal with their topological constraints and spatial organization.

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Background: Studying the patterns of protein-protein interactions (PPIs) is fundamental for understanding the structure and function of protein complexes. The exploration of the vast space of possible mutual configurations of interacting proteins and their contact zones is very time consuming and requires the proteomic expert knowledge.

Results: In this paper, we propose a novel tool containing a set of visual abstraction techniques for the guided exploration of PPI configuration space.

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The structural maintenance of chromosomes (SMC) family of proteins supports mitotic proliferation, meiosis, and DNA repair to control genomic stability. Impairments in chromosome maintenance are linked to rare chromosome breakage disorders. Here, we have identified a chromosome breakage syndrome associated with severe lung disease in early childhood.

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SMC/kleisin complexes form elongated annular structures, which are critical for chromosome segregation, genome maintenance, and the regulation of gene expression. We describe marked structural similarities between bacterial and eukaryotic SMC/kleisin partner proteins (designated here as "kite" proteins for kleisin interacting tandem winged-helix (WH) elements of SMC complexes). Kite proteins are integral parts of all prokaryotic SMC complexes and Smc5/6 but not cohesin and condensin.

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SMC5/6 is a highly conserved protein complex related to cohesin and condensin, which are the key components of higher-order chromatin structures. The SMC5/6 complex is essential for proliferation in yeast and is involved in replication fork stability and processing. However, the precise mechanism of action of SMC5/6 is not known.

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The MAGE (Melanoma-associated antigen) protein family members are structurally related to each other by a MAGE-homology domain comprised of 2 winged helix motifs WH/A and WH/B. This family specifically evolved in placental mammals although single homologs designated NSE3 (non-SMC element) exist in most eukaryotes. NSE3, together with its partner proteins NSE1 and NSE4 form a tight subcomplex of the structural maintenance of chromosomes SMC5-6 complex.

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Background: The Nse1, Nse3 and Nse4 proteins form a tight sub-complex of the large SMC5-6 protein complex. hNSE3/MAGEG1, the mammalian ortholog of Nse3, is the founding member of the MAGE (melanoma-associated antigen) protein family and the Nse4 kleisin subunit is related to the EID (E1A-like inhibitor of differentiation) family of proteins. We have recently shown that human MAGE proteins can interact with NSE4/EID proteins through their characteristic conserved hydrophobic pocket.

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Background: The SMC5-6 protein complex is involved in the cellular response to DNA damage. It is composed of 6-8 polypeptides, of which Nse1, Nse3 and Nse4 form a tight sub-complex. MAGEG1, the mammalian ortholog of Nse3, is the founding member of the MAGE (melanoma-associated antigen) protein family and Nse4 is related to the EID (E1A-like inhibitor of differentiation) family of transcriptional repressors.

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Apparitions and possessions can be taken as genuine spiritual events or as symptoms of psychopathology. We focus upon occasions when the two seemingly conflicting "interpretations" co-exist in order to explore these phenomena as kinds of boundary objects-polymorphous realities stable and graspable enough, yet belonging to different worlds at once. Related diagnostic knowledge is often uncertain and always incomplete.

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We previously searched for interactions between plant telomere-binding proteins and found that AtTRB1, from the single-myb-histone (Smh) family, interacts with the Arabidopsis POT1-like-protein, AtPOT1b, involved in telomere capping. Here we identify domains responsible for that interaction. We also map domains in AtTRB1 responsible for interactions with other Smh-family-members.

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