Soren Steffensen

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BACKGROUND Faithful segregation of the genome during mitosis requires interphase chromatin to be condensed into well-defined chromosomes. Chromosome condensation involves a multiprotein complex known as condensin that associates with chromatin early in prophase. Until now, genetic analysis of SMC subunits of the condensin complex in higher eukaryotic cells(More)
Nucleotide sequence analysis is increasingly being used to identify bacteria. In this work, a PCR assay based on degenerate primers was used to obtain the partial sequence of infB, the gene encoding translation initiation factor 2 (IF2), in 39 clinical isolates of different Enterobacteriaceae. The partial sequence encodes the GTP-binding domain of IF2.(More)
Sgt1 was described previously in yeast and humans to be a Hsp90 co-chaperone and required for kinetochore assembly. We have identified a mutant allele of Sgt1 in Drosophila and characterized its function. Mutations in sgt1 do not affect overall kinetochore assembly or spindle assembly checkpoint. sgt1 mutant cells enter less frequently into mitosis and(More)
'Cohesin' is a highly conserved multiprotein complex thought to be the primary effector of sister-chromatid cohesion in all eukaryotes. Cohesin complexes in budding yeast hold sister chromatids together from S phase until anaphase, but in metazoans, cohesin proteins dissociate from chromosomes and redistribute into the whole cell volume during prophase,(More)
The partially conserved Mad3/BubR1 protein is required during mitosis for the spindle assembly checkpoint (SAC). In meiosis, depletion causes an accelerated transit through prophase I and missegregation of achiasmate chromosomes in yeast [1], whereas in mice, reduced dosage leads to severe chromosome missegregation [2]. These observations indicate a meiotic(More)
Mammalian topoisomerase IIalpha (topo IIalpha) plays a vital role in the removal of topological complexities left on DNA during S phase. Here, we developed a new assay to selectively identify sites of catalytic activity of topo IIalpha with subcellular resolution. We show that topo IIalpha activity concentrates at replicating heterochromatin in late S in a(More)
Recently, we described llama antibody fragments (VHH) that can neutralize human immunodeficiency virus, type 1 (HIV-1). These VHH were obtained after selective elution of phages carrying an immune library raised against gp120 of HIV-1 subtype B/C CN54 with soluble CD4. We describe here a new, family-specific approach to obtain the largest possible diversity(More)
The Escherichia coli translation initiation factor IF2 is a 97 kDa protein which interacts with the initiator fMet-tRNAfMet, GTP and the ribosomal subunits during initiation of protein biosynthesis. For structural and functional investigations of the factor, we have raised and characterised monoclonal antibodies against E. coli IF2. Twelve epitopes have(More)
The functionally uncharacterised N-terminal of translation initiation factor IF2 has been found to be extremely variable when comparing different bacterial species. In order to study the intraspecies variability of IF2 the 2670 basepairs nucleotide sequence of the infB gene (encoding IF2) was determined in 10 clinical isolates of E. coli. The N-terminal(More)
Chemokines and chemokine receptors are key modulators in inflammatory diseases and malignancies. Here, we describe the identification and pharmacologic characterization of nanobodies selectively blocking CXCR2, the most promiscuous of all chemokine receptors. Two classes of selective monovalent nanobodies were identified, and detailed epitope mapping showed(More)