scholarly journals Stable inheritance of Sinorhizobium meliloti cell growth polarity requires an FtsN-like protein and an amidase

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Elizaveta Krol ◽  
Lisa Stuckenschneider ◽  
Joana M. Kästle Silva ◽  
Peter L. Graumann ◽  
Anke Becker
Keyword(s):  
Cell Division ◽  
Cell Polarity ◽  
Chromosome Segregation ◽  
Cell Elongation ◽  
Sinorhizobium Meliloti ◽  
Growth Zone ◽  
Cell Pole ◽  
Growth Polarity ◽  
Selection Of

AbstractIn Rhizobiales bacteria, such as Sinorhizobium meliloti, cell elongation takes place only at new cell poles, generated by cell division. Here, we show that the role of the FtsN-like protein RgsS in S. meliloti extends beyond cell division. RgsS contains a conserved SPOR domain known to bind amidase-processed peptidoglycan. This part of RgsS and peptidoglycan amidase AmiC are crucial for reliable selection of the new cell pole as cell elongation zone. Absence of these components increases mobility of RgsS molecules, as well as abnormal RgsS accumulation and positioning of the growth zone at the old cell pole in about one third of the cells. These cells with inverted growth polarity are able to complete the cell cycle but show partially impaired chromosome segregation. We propose that amidase-processed peptidoglycan provides a landmark for RgsS to generate cell polarity in unipolarly growing Rhizobiales.

scholarly journals Tol-Pal System and Rgs Proteins Interact to Promote Unipolar Growth and Cell Division in Sinorhizobium meliloti

mBio ◽  
2020 ◽  
Vol 11 (3) ◽  
Author(s):  
Elizaveta Krol ◽  
Hamish C. L. Yau ◽  
Marcus Lechner ◽  
Simon Schäper ◽  
Gert Bange ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Cell Growth ◽  
Cell Elongation ◽  
Sinorhizobium Meliloti ◽  
Rgs Proteins ◽  
Polar Growth ◽  
Content Type ◽  
Cell Pole ◽  
Growing Cell

ABSTRACT Sinorhizobium meliloti is an alphaproteobacterium belonging to the Rhizobiales. Bacteria from this order elongate their cell wall at the new cell pole, generated by cell division. Screening for protein interaction partners of the previously characterized polar growth factors RgsP and RgsM, we identified the inner membrane components of the Tol-Pal system (TolQ and TolR) and novel Rgs (rhizobial growth and septation) proteins with unknown functions. TolQ, Pal, and all Rgs proteins, except for RgsE, were indispensable for S. meliloti cell growth. Six of the Rgs proteins, TolQ, and Pal localized to the growing cell pole in the cell elongation phase and to the septum in predivisional cells, and three Rgs proteins localized to the growing cell pole only. The putative FtsN-like protein RgsS contains a conserved SPOR domain and is indispensable at the early stages of cell division. The components of the Tol-Pal system were required at the late stages of cell division. RgsE, a homolog of the Agrobacterium tumefaciens growth pole ring protein GPR, has an important role in maintaining the normal growth rate and rod cell shape. RgsD is a periplasmic protein with the ability to bind peptidoglycan. Analysis of the phylogenetic distribution of the Rgs proteins showed that they are conserved in Rhizobiales and mostly absent from other alphaproteobacterial orders, suggesting a conserved role of these proteins in polar growth. IMPORTANCE Bacterial cell proliferation involves cell growth and septum formation followed by cell division. For cell growth, bacteria have evolved different complex mechanisms. The most prevalent growth mode of rod-shaped bacteria is cell elongation by incorporating new peptidoglycans in a dispersed manner along the sidewall. A small share of rod-shaped bacteria, including the alphaproteobacterial Rhizobiales, grow unipolarly. Here, we identified and initially characterized a set of Rgs (rhizobial growth and septation) proteins, which are involved in cell division and unipolar growth of Sinorhizobium meliloti and highly conserved in Rhizobiales. Our data expand the knowledge of components of the polarly localized machinery driving cell wall growth and suggest a complex of Rgs proteins with components of the divisome, differing in composition between the polar cell elongation zone and the septum.

scholarly journals Tol-Pal system and Rgs proteins interact to promote unipolar growth and cell division in Sinorhizobium meliloti

2020 ◽  
Author(s):  
Elizaveta Krol ◽  
Hamish C. L. Yau ◽  
Marcus Lechner ◽  
Simon Schäper ◽  
Gert Bange ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Cell Growth ◽  
Cell Elongation ◽  
Sinorhizobium Meliloti ◽  
Normal Growth ◽  
Rgs Proteins ◽  
Polar Growth ◽  
Cell Pole ◽  
Growing Cell

ABSTRACTSinorhizobium meliloti is an α-proteobacterium belonging to the Rhizobiales. Bacteria from this order elongate their cell wall at the new cell pole, generated by cell division. Screening for protein interaction partners of the previously characterized polar growth factors RgsP and RgsM, we identified the inner membrane components of the Tol-Pal system (TolQ and TolR) and novel Rgs (rhizobial growth and septation) proteins with unknown functions. TolQ, Pal and all Rgs proteins, except for RgsE, were indispensable for S. meliloti cell growth. Six of the Rgs proteins, TolQ and Pal localized to the growing cell pole in the cell elongation phase and to the septum in pre-divisional cells, and three Rgs proteins localized to growing cell pole only. The FtsN-like protein RgsS contains a conserved SPOR domain and is indispensable at the early stages of cell division. The components of the Tol-Pal system were required at the late stages of cell division. RgsE, a homolog of the Agrobacterium tumefaciens growth pole ring protein GPR, has an important role in maintaining the normal growth rate and rod cell shape. RgsD is a novel periplasmic protein with the ability to bind peptidoglycan. Analysis of the phylogenetic distribution of novel Rgs proteins showed that they are conserved in Rhizobiales and mostly absent from other α-proteobacterial orders, suggesting a conserved role of these proteins in polar growth.IMPORTANCEBacterial cell proliferation involves cell growth and septum formation followed by cell division. For cell growth, bacteria have evolved different complex mechanisms. The most prevalent growth mode of rod shaped bacteria is cell elongation by incorporating new peptidoglycan in a dispersed manner along the sidewall. A small share of rod-shaped bacteria, including the α-proteobacterial Rhizobiales, grow unipolarly. Here, we identified and initially characterized a set of Rgs (rhizobial growth and septation) proteins, which are involved in cell division and unipolar growth of Sinorhizobium meliloti and highly conserved in Rhizobiales. Our data expand the knowledge of components of the polarly localized machinery driving cell wall growth and suggest a complex of Rgs proteins with components of the divisome, differing in composition between the polar cell elongation zone and the septum.

fumble Encodes a Pantothenate Kinase Homolog Required for Proper Mitosis and Meiosis in Drosophila melanogaster

Genetics ◽  
2001 ◽  
Vol 157 (3) ◽  
pp. 1267-1276
Author(s):  
Katayoun Afshar ◽  
Pierre Gönczy ◽  
Stephen DiNardo ◽  
Steven A Wasserman
Keyword(s):  
Cell Division ◽  
Chromosome Segregation ◽  
Cell Division Cycle ◽  
Protein Isoforms ◽  
Pantothenate Kinase ◽  
Male Germline ◽  
Dividing Cells ◽  
Mutant Cells ◽  
Mitosis And Meiosis

Abstract A number of fundamental processes comprise the cell division cycle, including spindle formation, chromosome segregation, and cytokinesis. Our current understanding of these processes has benefited from the isolation and analysis of mutants, with the meiotic divisions in the male germline of Drosophila being particularly well suited to the identification of the required genes. We show here that the fumble (fbl) gene is required for cell division in Drosophila. We find that dividing cells in fbl-deficient testes exhibit abnormalities in bipolar spindle organization, chromosome segregation, and contractile ring formation. Cytological analysis of larval neuroblasts from null mutants reveals a reduced mitotic index and the presence of polyploid cells. Molecular analysis demonstrates that fbl encodes three protein isoforms, all of which contain a domain with high similarity to the pantothenate kinases of A. nidulans and mouse. The largest Fumble isoform is dispersed in the cytoplasm during interphase, concentrates around the spindle at metaphase, and localizes to the spindle midbody at telophase. During early embryonic development, the protein localizes to areas of membrane deposition and/or rearrangement, such as the metaphase and cellularization furrows. Given the role of pantothenate kinase in production of Coenzyme A and in phospholipid biosynthesis, this pattern of localization is suggestive of a role for fbl in membrane synthesis. We propose that abnormalities in synthesis and redistribution of membranous structures during the cell division cycle underlie the cell division defects in fbl mutant cells.

scholarly journals The Drosophila Kinesin-like Protein KLP67A Is Essential for Mitotic and Male Meiotic Spindle Assembly

2004 ◽  
Vol 15 (1) ◽  
pp. 121-131 ◽  
Author(s):  
Rita Gandhi ◽  
Silvia Bonaccorsi ◽  
Diana Wentworth ◽  
Stephen Doxsey ◽  
Maurizio Gatti ◽  
...  
Keyword(s):  
Cell Division ◽  
Chromosome Segregation ◽  
Mutational Analysis ◽  
Spindle Assembly ◽  
Male Meiosis ◽  
Meiotic Spindle ◽  
Drosophila Cell ◽  
Centrosome Separation ◽  
Mutant Cells

We have performed a mutational analysis together with RNA interference to determine the role of the kinesin-like protein KLP67A in Drosophila cell division. During both mitosis and male meiosis, Klp67A mutations cause an increase in MT length and disrupt discrete aspects of spindle assembly, as well as cytokinesis. Mutant cells exhibit greatly enlarged metaphase spindle as a result of excessive MT polymerization. The analysis of both living and fixed cells also shows perturbations in centrosome separation, chromosome segregation, and central spindle assembly. These data demonstrate that the MT plus end-directed motor KLP67A is essential for spindle assembly during mitosis and male meiosis and suggest that the regulation of MT plus-end polymerization is a key determinant of spindle architecture throughout cell division.

scholarly journals First person – Victor Palacios

2021 ◽  
Vol 134 (7) ◽  
Keyword(s):  
Chromosome Segregation ◽  
Germ Cells ◽  
Medical Center ◽  
Early Career ◽  
First Person ◽  
University Of Texas ◽  
Early Career Researchers ◽  
The University ◽  
Selection Of

ABSTRACT First Person is a series of interviews with the first authors of a selection of papers published in Journal of Cell Science, helping early-career researchers promote themselves alongside their papers. Victor Palacios is first author on ‘Importin-9 regulates chromosome segregation and packaging in Drosophila germ cells’, published in JCS. Victor conducted his PhD research in the lab of Michael Buszczak at the University of Texas Southwestern Medical Center, Dallas, TX, where he investigated the essential role of Importin-9 in Drosophila fertility.

Budding in hydra: the role of cell multiplication and cell movement in bud initiation

Development ◽  
1972 ◽  
Vol 27 (2) ◽  
pp. 301-316
Author(s):  
Gerald Webster ◽  
Susan Hamilton
Keyword(s):  
Cell Division ◽  
Mitotic Index ◽  
Cell Population ◽  
Cell Movement ◽  
Growth Zone ◽  
Cell Multiplication ◽  
Rapid Rise ◽  
The Mean ◽  
Bud Initiation

The work described in this paper is concerned with the role of cell multiplication and cell movement in relation to the initiation of buds in hydra. Hydra starved for 6 days do not initiate new buds; in such animals the mean mitotic index is only 10% of that in well-fed animals. When starved animals are re-fed, there is a rapid rise in mitotic index which reaches a maximum 12 h after feeding and thereafter declines. This cell division causes an increase in the cell population of about 30% in the 24 h following the meal. New buds are initiated at 24–72 h, i.e. at some time after the major part of the cell multiplication. Cell division occurs in all parts of the axis to more or less the same extent and there is no sign of a growth zone in the budding region. However, the cell population in the budding zone of re-fed animals shows a significantly greater increase than in other parts of the axis and this can only be accounted for if it is assumed that cells have moved into this region from other parts of the axis. Some cell multiplication is a necessary prerequisite for bud initiation, but grafting experiments with starved animals suggest that division per se is not necessary; the important factor seems to be the increase in size resulting from division. The mechanics and causes of the cell movement which results in bud initiation are briefly discussed. It is suggested that changes in intercellular adhesion may be important.

scholarly journals CENP-C is a blueprint for constitutive centromere–associated network assembly within human kinetochores

2015 ◽  
Vol 210 (1) ◽  
pp. 11-22 ◽  
Author(s):  
Kerstin Klare ◽  
John R. Weir ◽  
Federica Basilico ◽  
Tomasz Zimniak ◽  
Lucia Massimiliano ◽  
...  
Keyword(s):  
Cell Division ◽  
Chromosome Segregation ◽  
The Other ◽  
Microtubule Binding ◽  
Kinetochore Assembly ◽  
Binding Interface ◽  
Other Hand ◽  
Spindle Microtubules ◽  
Data Point

Kinetochores are multisubunit complexes that assemble on centromeres to bind spindle microtubules and promote faithful chromosome segregation during cell division. A 16-subunit complex named the constitutive centromere–associated network (CCAN) creates the centromere–kinetochore interface. CENP-C, a CCAN subunit, is crucial for kinetochore assembly because it links centromeres with the microtubule-binding interface of kinetochores. The role of CENP-C in CCAN organization, on the other hand, had been incompletely understood. In this paper, we combined biochemical reconstitution and cellular investigations to unveil how CENP-C promotes kinetochore targeting of other CCAN subunits. The so-called PEST domain in the N-terminal half of CENP-C interacted directly with the four-subunit CCAN subcomplex CENP-HIKM. We identified crucial determinants of this interaction whose mutation prevented kinetochore localization of CENP-HIKM and of CENP-TW, another CCAN subcomplex. When considered together with previous observations, our data point to CENP-C as a blueprint for kinetochore assembly.

Cell Polarity and Migration: Emerging Role for the Endosomal Sorting Machinery

Physiology ◽  
2011 ◽  
Vol 26 (3) ◽  
pp. 171-180 ◽  
Author(s):  
Viola Hélène Lobert ◽  
Harald Stenmark
Keyword(s):  
Cell Migration ◽  
Cell Division ◽  
Cell Polarity ◽  
Tumor Suppressors ◽  
Potential Role ◽  
Endosomal Sorting ◽  
Escrt Machinery ◽  
Viral Budding ◽  
And Migration

The endosomal sorting complex required for transport (ESCRT) machinery has been implicated in the regulation of endosomal sorting, cell division, viral budding, autophagy, and cell signaling. Here, we review recent evidence that implicates ESCRTs in cell polarity and cell migration, and discuss the potential role of ESCRTs as tumor suppressors.

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