Acyl carrier protein promotes MukBEF action in Escherichia coli chromosome organization-segregation.

Structural Maintenance of Chromosomes (SMC) complexes act ubiquitously to compact DNA linearly, thereby facilitating chromosome organization-segregation. SMC proteins have a conserved architecture, with a dimerization hinge and an ATPase head domain separated by a long antiparallel intramolecular coiled-coil. Dimeric SMC proteins interact with essential accessory proteins, kleisins that bridge the two subunits of an SMC dimer, and HAWK/KITE proteins that interact with kleisins.

Competitive binding of MatP and topoisomerase IV to the MukB hinge domain.

Structural Maintenance of Chromosomes (SMC) complexes have ubiquitous roles in compacting DNA linearly, thereby promoting chromosome organization-segregation. Interaction between the SMC complex, MukBEF, and -bound MatP in the chromosome replication termination region, , results in depletion of MukBEF from , a process essential for efficient daughter chromosome individualization and for preferential association of MukBEF with the replication origin region. Chromosome-associated MukBEF complexes also interact with topoisomerase IV (ParCE), so that their chromosome distribution mirrors that of MukBEF.

Nonrandom segregation of sister chromosomes by MukBEF.

Structural maintenance of chromosomes (SMC) complexes contribute to chromosome organization in all domains of life. In , MukBEF, the functional SMC homolog, promotes spatiotemporal chromosome organization and faithful chromosome segregation. Here, we address the relative contributions of MukBEF and the replication terminus () binding protein, MatP, to chromosome organization-segregation.

MUK OPTIMUM protocol: a screening study to identify high-risk patients with multiple myeloma suitable for novel treatment approaches combined with a phase II study evaluating optimised combination of biological therapy in newly diagnosed high-risk multiple myeloma and plasma cell leukaemia.

Introduction: Multiple myeloma (MM) is a plasma cell tumour with over 5800 new cases each year in the UK. The introduction of biological therapies has improved outcomes for the majority of patients with MM, but in approximately 20% of patients the tumour is characterised by genetic changes which confer a significantly poorer prognosis, generally termed high-risk (HR) MM. It is important to diagnose these genetic changes early and identify more effective first-line treatment options for these patients.

Transient non-specific DNA binding dominates the target search of bacterial DNA-binding proteins.

Despite their diverse biochemical characteristics and functions, all DNA-binding proteins share the ability to accurately locate their target sites among the vast excess of non-target DNA. Toward identifying universal mechanisms of the target search, we used single-molecule tracking of 11 diverse DNA-binding proteins in living Escherichia coli. The mobility of these proteins during the target search was dictated by DNA interactions rather than by their molecular weights.

Bortezomib, Vorinostat, and Dexamethasone Combination Therapy in Relapsed Myeloma: Results of the Phase 2 MUK four Trial.

Introduction: Outcomes continue to improve in relapsed myeloma as more effective treatment options emerge. We report a multicenter single-arm phase 2 trial evaluating toxicity and efficacy of the histone deacetylase (HDAC) inhibitor vorinostat in combination with bortezomib and dexamethasone.

Patients And Methods: Sixteen patients who had received a median of 1 prior treatment line received bortezomib subcutaneously 1.

Experiences of a new cadre of midwives in Bangladesh: findings from a mixed method study.

Background: Bangladesh did not have dedicated professional midwives in public sector health facilities until recently, when the country started a nation-wide programme to educate and deploy diploma midwives. The objective of the findings presented in this paper, which is part of a larger study, was to better understand the experience of the midwives of their education programme and first posting as a qualified midwife and to assess their midwifery knowledge and skills.

Methods: We applied a mixed method approach, which included interviewing 329 midwives and conducting 6 focus group discussions with 43 midwives and midwifery students.

The MUK eight protocol: a randomised phase II trial of cyclophosphamide and dexamethasone in combination with ixazomib, in relapsed or refractory multiple myeloma (RRMM) patients who have relapsed after treatment with thalidomide, lenalidomide and a proteasome inhibitor.

Background: Multiple myeloma is a plasma cell tumour with approximately 5500 new cases in the UK each year. Ixazomib is a next generation inhibitor of the 20S proteasome and is thought to be an effective treatment for those who have relapsed from bortezomib. The combination of cyclophosphamide and dexamethasone (CD) is a recognised treatment option for patients with relapsed refractory multiple myeloma (RRMM) who have relapsed after treatment with bortezomib and lenalidomide, whilst also often being combined with newer proteasome inhibitors.

Functional Analysis of the XerC and XerD Site-Specific Recombinases: Potential Role in Dissemination of Resistance Genes.

Modules composed of a resistance gene flanked by Xer site-specific recombination sites, the vast majority of which were found in , are thought to behave as elements that facilitate horizontal dissemination. The and genes were cloned, and the recombinant clones used to complement the cognate mutants. The complemented strains supported the resolution of plasmid dimers, and, as is the case with and plasmids, the activity was enhanced when the cells were grown in a low osmolarity growth medium.

SMC complexes organize the bacterial chromosome by lengthwise compaction.

Structural maintenance of chromosomes (SMC) complexes are ancient and conserved molecular machines that organize chromosomes in all domains of life. We propose that the principles of chromosome folding needed to accommodate DNA inside a cell in an accessible form will follow similar principles in prokaryotes and eukaryotes. However, the exact contributions of SMC complexes to bacterial chromosome organization have been elusive.

Organization of the Escherichia coli Chromosome by a MukBEF Axial Core.

Structural maintenance of chromosomes (SMC) complexes organize chromosomes ubiquitously, thereby contributing to their faithful segregation. We demonstrate that under conditions of increased chromosome occupancy of the Escherichia coli SMC complex, MukBEF, the chromosome is organized as a series of loops around a thin (<130 nm) MukBEF axial core, whose length is ∼1,100 times shorter than the chromosomal DNA. The linear order of chromosomal loci is maintained in the axial cores, whose formation requires MukBEF ATP hydrolysis.

Small Plasmids: Neglected Contributors to Antibiotic Resistance.

is the causative agent of community- and, more commonly, hospital-acquired infections. Infections caused by this bacterium have recently become more dangerous due to the acquisition of multiresistance to antibiotics and the rise of hypervirulent variants. Plasmids usually carry genes coding for resistance to antibiotics or virulence factors, and the recent sequence of complete genomes showed that most strains harbor many of them.

Dynamic architecture of the Escherichia coli structural maintenance of chromosomes (SMC) complex, MukBEF.

Ubiquitous Structural Maintenance of Chromosomes (SMC) complexes use a proteinaceous ring-shaped architecture to organize and individualize chromosomes, thereby facilitating chromosome segregation. They utilize cycles of adenosine triphosphate (ATP) binding and hydrolysis to transport themselves rapidly with respect to DNA, a process requiring protein conformational changes and multiple DNA contact sites. By analysing changes in the architecture and stoichiometry of the Escherichia coli SMC complex, MukBEF, as a function of nucleotide binding to MukB and subsequent ATP hydrolysis, we demonstrate directly the formation of dimer of MukBEF dimer complexes, dependent on dimeric MukF kleisin.

Self-organised segregation of bacterial chromosomal origins.

The chromosomal replication origin region () of characterised bacteria is dynamically positioned throughout the cell cycle. In slowly growing , is maintained at mid-cell from birth until its replication, after which newly replicated sister s move to opposite quarter positions. Here, we provide an explanation for positioning based on the self-organisation of the Structural Maintenance of Chromosomes complex, MukBEF, which forms dynamically positioned clusters on the chromosome.

The bacterial cell cycle, chromosome inheritance and cell growth.

All viable bacterial cells, whether they divide symmetrically or asymmetrically, must coordinate their growth, division, cell volume and shape with the inheritance of the genome. These coordinated processes maintain genome integrity over generations as chromosomes are duplicated and segregated during each cell cycle, and include the organization of DNA into nucleoids, controlled and faithful DNA replication, chromosome unlinking and faithful segregation into daughter cells. In this Review, we explore the contributions of chromosome structure and nucleoid organization to cell cycle regulation, detail the cellular processes involved in the initiation of DNA replication and DNA segregation and explore how those processes are linked to cell growth and cell division.

Single-molecule imaging of DNA gyrase activity in living Escherichia coli.

Bacterial DNA gyrase introduces negative supercoils into chromosomal DNA and relaxes positive supercoils introduced by replication and transiently by transcription. Removal of these positive supercoils is essential for replication fork progression and for the overall unlinking of the two duplex DNA strands, as well as for ongoing transcription. To address how gyrase copes with these topological challenges, we used high-speed single-molecule fluorescence imaging in live Escherichia coli cells.

Competition between DivIVA and the nucleoid for ParA binding promotes segrosome separation and modulates mycobacterial cell elongation.

Although mycobacteria are rod shaped and divide by simple binary fission, their cell cycle exhibits unusual features: unequal cell division producing daughter cells that elongate with different velocities, as well as asymmetric chromosome segregation and positioning throughout the cell cycle. As in other bacteria, mycobacterial chromosomes are segregated by pair of proteins, ParA and ParB. ParA is an ATPase that interacts with nucleoprotein ParB complexes - segrosomes and non-specifically binds the nucleoid.

MukB ATPases are regulated independently by the N- and C-terminal domains of MukF kleisin.

The SMC complex, MukBEF, acts in chromosome segregation. MukBEF shares the distinctive architecture of other SMC complexes, with one prominent difference; unlike other kleisins, MukF forms dimers through its N-terminal domain. We show that a 4-helix bundle adjacent to the MukF dimerisation domain interacts functionally with the MukB coiled-coiled 'neck' adjacent to the ATPase head.

Direct observation of end resection by RecBCD during double-stranded DNA break repair in vivo.

The formation of 3' single-stranded DNA overhangs is a first and essential step during homology-directed repair of double-stranded breaks (DSB) of DNA, a task that in Escherichia coli is performed by RecBCD. While this protein complex has been well characterized through in vitro single-molecule studies, it has remained elusive how end resection proceeds in the crowded and complex environment in live cells. Here, we develop a two-color fluorescent reporter to directly observe the resection of individual inducible DSB sites within live E.

Pathways of DNA unlinking: A story of stepwise simplification.

In Escherichia coli DNA replication yields interlinked chromosomes. Controlling topological changes associated with replication and returning the newly replicated chromosomes to an unlinked monomeric state is essential to cell survival. In the absence of the topoisomerase topoIV, the site-specific recombination complex XerCD- dif-FtsK can remove replication links by local reconnection.

Experiences of establishing an academic early phase clinical trials unit.

Background: Early phase trials are essential in drug development, determining appropriate dose levels and assessing preliminary activity. These trials are undertaken by industry and academia, with increasing collaborations between the two. There is pressure to perform these trials quickly, safely, and robustly.

Exploring global recognition of quality midwifery education: Vision or fiction?

Background: Midwifery education is the foundation for preparing competent midwives to provide a high standard of safe, evidence-based care for women and their newborns. Global competencies and standards for midwifery education have been defined as benchmarks for establishing quality midwifery education and practice worldwide. However, wide variations in type and nature of midwifery education programs exist.