scholarly journals Integrase Mutants Defective for Interaction with LEDGF/p75 Are Impairedin Chromosome Tethering and HIV-1Replication*

2005 ◽  
Vol 280 (27) ◽  
pp. 25517-25523 ◽  
Author(s):  
Stéphane Emiliani ◽  
Aurélie Mousnier ◽  
Katrien Busschots ◽  
Marlène Maroun ◽  
Bénédicte Van Maele ◽  
...  
Keyword(s):  
Chromosome Tethering

scholarly journals tRNA Genes Affect Chromosome Structure and Function via Local Effects

2019 ◽  
Vol 39 (8) ◽  
Author(s):  
Omar Hamdani ◽  
Namrita Dhillon ◽  
Tsung-Han S. Hsieh ◽  
Takahiro Fujita ◽  
Josefina Ocampo ◽  
...  
Keyword(s):  
Long Range ◽  
Binding Sites ◽  
Genomic Organization ◽  
Chromosome Structure ◽  
Trna Genes ◽  
Local Effects ◽  
Chromosome Architecture ◽  
Architectural Proteins ◽  
And Function ◽  
Chromosome Tethering

ABSTRACT The genome is packaged and organized in an ordered, nonrandom manner, and specific chromatin segments contact nuclear substructures to mediate this organization. tRNA genes (tDNAs) are binding sites for transcription factors and architectural proteins and are thought to play an important role in the organization of the genome. In this study, we investigate the roles of tDNAs in genomic organization and chromosome function by editing a chromosome so that it lacked any tDNAs. Surprisingly our analyses of this tDNA-less chromosome show that loss of tDNAs does not grossly affect chromatin architecture or chromosome tethering and mobility. However, loss of tDNAs affects local nucleosome positioning and the binding of SMC proteins at these loci. The absence of tDNAs also leads to changes in centromere clustering and a reduction in the frequency of long-range HML-HMR heterochromatin clustering with concomitant effects on gene silencing. We propose that the tDNAs primarily affect local chromatin structure, which results in effects on long-range chromosome architecture.

scholarly journals The chromatin-tethering domain of human cytomegalovirus immediate-early (IE) 1 mediates associations of IE1, PML and STAT2 with mitotic chromosomes, but is not essential for viral replication

2012 ◽  
Vol 93 (4) ◽  
pp. 716-721 ◽  
Author(s):  
Hye Jin Shin ◽  
Young-Eui Kim ◽  
Eui Tae Kim ◽  
Jin-Hyun Ahn
Keyword(s):  
Viral Replication ◽  
Human Cytomegalovirus ◽  
Immediate Early ◽  
Wild Type Virus ◽  
Type Virus ◽  
Virus Infections ◽  
Wild Type ◽  
Mitotic Chromosomes ◽  
Carboxyl Terminal ◽  
Chromosome Tethering

Human cytomegalovirus (HCMV) immediate-early (IE) 1 protein associates with chromosomes in mitotic cells using its carboxyl-terminal 16 aa region. However, the role of this IE1 activity in viral growth has not been evaluated in the context of mutant virus infection. We produced a recombinant HCMV encoding mutant IE1 with the carboxyl-terminal chromosome-tethering domain (CTD) deleted. This IE1(ΔCTD) virus grew like the wild-type virus in fibroblasts, indicating that the CTD is not essential for viral replication in permissive cells. Unlike wild-type virus infections, PML and STAT2, which interact with IE1, did not accumulate at mitotic chromosomes in IE1(ΔCTD) virus-infected fibroblasts, demonstrating that their associations with chromosomes are IE1 CTD-dependent. IE1 SUMOylation did not affect IE1 association with chromosomes. Our results provide genetic evidence that the CTD is required for the associations of IE1, PML and STAT2 with mitotic chromosomes, but that these IE1-related activities are not essential for viral replication in fibroblasts.

scholarly journals DNA-Membrane Anchor Facilitates Efficient Chromosome Translocation at a Distance inBacillus subtilis

mBio ◽  
2019 ◽  
Vol 10 (3) ◽  
Author(s):  
Nikolai P. Radzinski ◽  
Marina Besprozvannaya ◽  
Eric L. McLean ◽  
Anusha Talwalkar ◽  
Briana M. Burton
Keyword(s):  
Chromosome Segregation ◽  
Chromosome Translocation ◽  
Similar Degree ◽  
Cell Physiology ◽  
Membrane Anchor ◽  
Content Type ◽  
Dna Capture ◽  
Secondary Function ◽  
Membrane Tether ◽  
Chromosome Tethering

ABSTRACTChromosome segregation in sporulatingBacillus subtilisinvolves the tethering of sister chromosomes at opposite cell poles. RacA is known to mediate chromosome tethering by interacting with both centromere-like elements in the DNA and with DivIVA, a membrane protein which localizes to the cell poles. RacA has a secondary function in which it assists in nucleoid condensation. Here we demonstrate that, in addition to positioning and condensing the chromosome, RacA contributes to efficient transport of DNA by the chromosome segregation motor SpoIIIE. When RacA is deleted, one-quarter of cells fail to capture DNA in the nascent spore, yet 70% of cells fail to form viable spores without RacA. This discrepancy indicates that RacA possesses a role in sporulation beyond DNA capture and condensation. We observed that the mutant cells had reduced chromosome translocation into the forespore across the entire length of the chromosome, requiring nearly twice as much time to move a given DNA locus. Additionally, functional abolition of the RacA-DivIVA interaction reduced translocation to a similar degree as in aracAdeletion strain, demonstrating the importance of the RacA-mediated tether in translocation and chromosome packaging during sporulation. We propose that the DNA-membrane anchor facilitates efficient translocation by SpoIIIE, not through direct protein-protein contacts but by virtue of physical effects on the chromosome that arise from anchoring DNA at a distance.IMPORTANCETo properly segregate their chromosomes, organisms tightly regulate the organization and dynamics of their DNA. Aspects of the process by which DNA is translocated during sporulation are not yet fully understood, such as what factors indirectly influence the activity of the motor protein SpoIIIE. In this work, we have shown that a DNA-membrane tether mediated by RacA contributes to the activity of SpoIIIE. Loss of RacA nearly doubles the time of translocation, despite the physically distinct locations these proteins and their activities occupy within the cell. This is a rare example of an explicit effect that DNA-membrane connections can have on cell physiology and demonstrates that distant changes to the state of the chromosome can influence motor proteins which act upon it.

scholarly journals Metaphase Chromosome Tethering Is Necessary for the DNA Synthesis and Maintenance of oriP Plasmids but Is Insufficient for Transcription Activation by Epstein-Barr Nuclear Antigen 1

2003 ◽  
Vol 77 (21) ◽  
pp. 11767-11780 ◽  
Author(s):  
John Sears ◽  
John Kolman ◽  
Geoffrey M. Wahl ◽  
Ashok Aiyar
Keyword(s):  
Metaphase Chromosome ◽  
Transcription Activation ◽  
Nuclear Antigen ◽  
Chromatin Binding ◽  
Metaphase Chromosomes ◽  
Barr Virus ◽  
Epstein Barr ◽  
Stable Maintenance ◽  
Chromosome Tethering ◽  
Fundamental Requirement

ABSTRACT Epstein-Barr Virus (EBV) infects resting B cells, within which it establishes latency as a stable, circular episome with only two EBV components, the cis element oriP and the latently expressed protein EBNA1. It is believed that EBNA1's ability to tether oriP episomes to metaphase chromosomes is required for its stable replication. We created fusions between the DNA-binding domain (DBD) of EBNA1 and the cellular chromatin-binding proteins HMGA1a and HMG1 to determine the minimal requirements for stable maintenance of an oriP-based episome. These two proteins differ in that HMGA1a can associate with metaphase chromosomes but HMG1 cannot. Interestingly, coinciding with metaphase chromosome association, HMGA1a-DBD but not HMG1-DBD supported both the transient replication and stable maintenance of oriP plasmids, with efficiencies quantitatively similar to that of EBNA1. However, HMGA1a-DBD activated transcription from EBNA1-dependent episomal reporter to only 20% of the level of EBNA1. Furthermore, EBNA1 but not HMGA1a-DBD activated transcription from a chromosomally integrated EBNA1-dependent transcription reporter. This indicates that EBNA1 possesses functional domains that support transcription activation independent of its ability to tether episomal oriP plasmids to cellular chromosomes. We provide evidence that metaphase chromosome tethering is a fundamental requirement for maintenance of an oriP plasmid but is insufficient for EBNA1 to activate transcription.

scholarly journals Role for perinuclear chromosome tethering in maintenance of genome stability

Nature ◽  
2008 ◽  
Vol 456 (7222) ◽  
pp. 667-670 ◽  
Author(s):  
Karim Mekhail ◽  
Jan Seebacher ◽  
Steven P. Gygi ◽  
Danesh Moazed
Keyword(s):  
Genome Stability ◽  
Chromosome Tethering

scholarly journals Effect of Chromosome Tethering on Nuclear Organization in Yeast

PLoS ONE ◽  
2014 ◽  
Vol 9 (7) ◽  
pp. e102474 ◽  
Author(s):  
Barış Avşaroğlu ◽  
Gabriel Bronk ◽  
Susannah Gordon-Messer ◽  
Jungoh Ham ◽  
Debra A. Bressan ◽  
...  
Keyword(s):  
Nuclear Organization ◽  
Chromosome Tethering

Mitotic segregation of viral and cellular acentric extrachromosomal molecules by chromosome tethering

2001 ◽  
Vol 114 (1) ◽  
pp. 49-58 ◽  
Author(s):  
T. Kanda ◽  
M. Otter ◽  
G.M. Wahl
Keyword(s):  
Epstein Barr Virus ◽  
Fluorescent Protein ◽  
Lac Repressor ◽  
Virus Vectors ◽  
Barr Virus ◽  
Daughter Cells ◽  
Double Minute ◽  
Epstein Barr ◽  
Chromosome Tethering ◽  
Double Minute Chromosomes

Mitotic chromosome segregation is mediated by spindle microtubules attached to centromeres. Recent studies, however, revealed that acentric DNA molecules, such as viral replicons and double minute chromosomes, can efficiently segregate into daughter cells by associating with mitotic chromosomes. Based on this similarity between viral and cellular acentric molecules, we introduced Epstein-Barr virus vectors into cells harboring double minute chromosomes and compared their mitotic behaviors. We added lac operator repeats to an Epstein-Barr virus vector, which enabled us to readily identify the transgene in cells expressing a fusion protein between the lac repressor and green fluorescent protein. Unexpectedly, we found that Epstein-Barr virus vectors integrated into the acentric double minute chromosomes, but not into normal chromosomes, in all of the six stably transfected clones examined. While transiently transfected Epstein-Barr virus vectors randomly associated with wheel-shaped prometaphase chromosome rosettes, the chimeras of double minute chromosomes and Epstein-Barr virus vectors in stably transfected clones always attached to the periphery of chromosome rosettes. These chimeric acentric molecules faithfully represented the behavior of native double minute chromosomes, providing a tool for analyzing their behavior in living cells throughout the cell cycle. Further detailed analyses, including real-time observations, revealed that double minute chromosomes appeared to be repelled from the spindle poles at the same time that they attached to the chromosome periphery, while centromeric regions were pulled poleward by the attached microtubules. Disrupting microtubule organization eliminated such peripheral localization of double minute chromosomes, but it did not affect their association with chromosomes. The results suggest a model in which double minute chromosomes, but not Epstein-Barr virus vectors, are subject to the microtubule-mediated antipolar force, while they both employ chromosome tethering strategies to increase their segregation to daughter cells.

scholarly journals Transfer RNA Genes Affect Chromosome Structure and Function via Local Effects

2018 ◽  
Author(s):  
Omar Hamdani ◽  
Namrita Dhillon ◽  
Tsung-Han S. Hsieh ◽  
Takahiro Fujita ◽  
Josefina Ocampo ◽  
...  
Keyword(s):  
Long Range ◽  
Binding Sites ◽  
Transfer Rna ◽  
Chromosome Architecture ◽  
Architectural Proteins ◽  
Random Manner ◽  
And Function ◽  
Chromosome Tethering ◽  
Rna Genes

AbstractThe genome is packaged and organized in an ordered, non-random manner and specific chromatin segments contact nuclear substructures to mediate this organization. While transfer RNA genes (tDNAs) are essential for the generation of tRNAs, these loci are also binding sites for transcription factors and architectural proteins and are thought to play an important role in the organization of the genome. In this study, we investigate the role of tDNAs in genomic organization and chromosome function by editing a chromosome so that it lacks any tDNAs. Surprisingly our analyses of this tDNA-less chromosome show that loss of tDNAs does not grossly affect chromosome folding or chromosome tethering. However, loss of tDNAs affects local nucleosome positioning and the binding of SMC proteins at these loci. The absence of tDNAs also leads to changes in centromere clustering and a reduction in the frequency of long range HML-HMR heterochromatin clustering. We propose that the tDNAs primarily affect local chromatin structure that result in effects on long-range chromosome architecture.

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