scholarly journals Telomere length regulation and transcriptional silencing in KU80-deficient Trypanosoma brucei

2004 ◽  
Vol 32 (22) ◽  
pp. 6575-6584 ◽  
Author(s):  
C. J. Janzen
Keyword(s):  
Telomere Length ◽  
Trypanosoma Brucei ◽  
Transcriptional Silencing ◽  
Length Regulation ◽  
Telomere Length Regulation

scholarly journals Rif1 regulates telomere length through conserved HEAT repeats

2021 ◽  
Vol 49 (7) ◽  
pp. 3967-3980
Author(s):  
Calla B Shubin ◽  
Rini Mayangsari ◽  
Ariel D Swett ◽  
Carol W Greider
Keyword(s):  
Dna Binding ◽  
Telomere Length ◽  
Functional Role ◽  
Conserved Residues ◽  
Binding Interface ◽  
Binding Function ◽  
Length Regulation ◽  
Telomere Length Regulation ◽  
Telomere Regulation ◽  
Conserved Amino Acids

AbstractIn budding yeast, Rif1 negatively regulates telomere length, but the mechanism of this regulation has remained elusive. Previous work identified several functional domains of Rif1, but none of these has been shown to mediate telomere length. To define Rif1 domains responsible for telomere regulation, we localized truncations of Rif1 to a single specific telomere and measured telomere length of that telomere compared to bulk telomeres. We found that a domain in the N-terminus containing HEAT repeats, Rif1177–996, was sufficient for length regulation when tethered to the telomere. Charged residues in this region were previously proposed to mediate DNA binding. We found that mutation of these residues disrupted telomere length regulation even when Rif1 was tethered to the telomere. Mutation of other conserved residues in this region, which were not predicted to interact with DNA, also disrupted telomere length maintenance, while mutation of conserved residues distal to this region did not. Our data suggest that conserved amino acids in the region from 436 to 577 play a functional role in telomere length regulation, which is separate from their proposed DNA binding function. We propose that the Rif1 HEAT repeats region represents a protein-protein binding interface that mediates telomere length regulation.

scholarly journals Cdc13 N-Terminal Dimerization, DNA Binding, and Telomere Length Regulation

2010 ◽  
Vol 30 (22) ◽  
pp. 5325-5334 ◽  
Author(s):  
Meghan T. Mitchell ◽  
Jasmine S. Smith ◽  
Mark Mason ◽  
Sandy Harper ◽  
David W. Speicher ◽  
...  
Keyword(s):  
Dna Binding ◽  
Telomere Length ◽  
Functional Characterization ◽  
Point Mutations ◽  
Telomeric Dna ◽  
Dna Binding Domains ◽  
Binding Domains ◽  
Length Regulation ◽  
Telomere Length Regulation

ABSTRACT The essential yeast protein Cdc13 facilitates chromosome end replication by recruiting telomerase to telomeres, and together with its interacting partners Stn1 and Ten1, it protects chromosome ends from nucleolytic attack, thus contributing to genome integrity. Although Cdc13 has been studied extensively, the precise role of its N-terminal domain (Cdc13N) in telomere length regulation remains unclear. Here we present a structural, biochemical, and functional characterization of Cdc13N. The structure reveals that this domain comprises an oligonucleotide/oligosaccharide binding (OB) fold and is involved in Cdc13 dimerization. Biochemical data show that Cdc13N weakly binds long, single-stranded, telomeric DNA in a fashion that is directly dependent on domain oligomerization. When introduced into full-length Cdc13 in vivo, point mutations that prevented Cdc13N dimerization or DNA binding caused telomere shortening or lengthening, respectively. The multiple DNA binding domains and dimeric nature of Cdc13 offer unique insights into how it coordinates the recruitment and regulation of telomerase access to the telomeres.

scholarly journals Regulating telomere length from the inside out: The replication fork model

2016 ◽  
Author(s):  
Carol W Greider
Keyword(s):  
Telomere Length ◽  
Alternative Model ◽  
Replication Fork ◽  
Molecular Level ◽  
Origin Firing ◽  
Length Regulation ◽  
Telomere Length Regulation ◽  
Inside Out ◽  
Counting Model

Telomere length is regulated around an equilibrium set point. Telomeres shorten during replication and are lengthened by telomerase. Disruption of the length equilibrium leads to disease, thus it is important to understand the mechanisms that regulate length at the molecular level. The prevailing protein counting model for regulating telomerase access to elongate the telomere does not explain accumulating evidence of a role of DNA replication in telomere length regulation. Here I present an alternative model: the replication fork model that can explain how passage of a replication fork and regulation of origin firing affect telomere length.

scholarly journals Minishelterins separate telomere length regulation and end protection in fission yeast

2015 ◽  
Vol 29 (11) ◽  
pp. 1164-1174 ◽  
Author(s):  
Lili Pan ◽  
Katie Hildebrand ◽  
Cian Stutz ◽  
Nicolas Thomä ◽  
Peter Baumann
Keyword(s):  
Fission Yeast ◽  
Telomere Length ◽  
Length Regulation ◽  
Telomere Length Regulation

DNA Binding and Telomere Length Regulation of Yeast RAP1 Homologues

2003 ◽  
Vol 332 (4) ◽  
pp. 821-833 ◽  
Author(s):  
Johan Wahlin ◽  
Monika Rosén ◽  
Marita Cohn
Keyword(s):  
Dna Binding ◽  
Telomere Length ◽  
Length Regulation ◽  
Telomere Length Regulation

scholarly journals Mechanisms of the Evolutionary Chromosome Plasticity: Integrating the ‘Centromere-from-Telomere' Hypothesis with Telomere Length Regulation

2016 ◽  
Vol 148 (4) ◽  
pp. 268-278 ◽  
Author(s):  
Predrag Slijepcevic
Keyword(s):  
Telomere Length ◽  
Length Distribution ◽  
Adaptive Responses ◽  
Eukaryotic Chromosome ◽  
Free Dna ◽  
Length Regulation ◽  
Telomere Length Regulation ◽  
Dna Ends ◽  
Size Gradient ◽  
Insight Into

The ‘centromere-from-telomere' hypothesis proposed by Villasante et al. [2007a] aims to explain the evolutionary origin of the eukaryotic chromosome. The hypothesis is based on the notion that the process of eukaryogenesis was initiated by adaptive responses of the symbiont eubacterium and its archaeal host to their new conditions. The adaptive responses included fragmentation of the circular genome of the host into multiple linear fragments with free DNA ends. The action of mobile genetic elements stabilized the free DNA ends resulting in the formation of proto-telomeres. Sequences next to the proto-telomeres, the subtelomeric sequences, were immediately targeted as the new cargo by the tubulin-based cytoskeleton, thus becoming proto-centromeres. A period of genomic instability followed. Eventually, functioning centromeres and telomeres emerged heralding the arrival of the eukaryotic chromosome in the evolution. This paper expands the ‘centromere-from-telomere' hypothesis by integrating it with 2 sets of data: chromosome-specific telomere length distribution and chromomere size gradient. The integration adds a new dimension to the hypothesis but also provides an insight into the mechanisms of chromosome plasticity underlying karyotype evolution.

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