<i>Saccharomyces cerevisiae</i> telomerase subunit Est3p binds DNA and RNA and stimulates unwinding of RNA/DNA heteroduplexes

Sharanov, Yu.S.; Zvereva, Maria I.; Донцова, О. А.

doi:10.1016/j.febslet.2006.07.048

Cited by 11 publications

(5 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…DNA-binding activity and proposed to act as the anchor site for the complex (20)(21)(22). In contrast, not withstanding an earlier report, we and others had been unable to detect a DNA-binding activity for ScEst3 and CaEst3 (9,11,23). The direct physical interaction between Est3 and TEN domain raises the interesting possibility that they may influence each other's nucleic acid-binding properties.…”

Section: Resultscontrasting

confidence: 46%

See 1 more Smart Citation

Telomerase regulatory subunit Est3 in two Candida species physically interacts with the TEN domain of TERT and telomeric DNA

Yen

Chico

Lei

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

The yeast telomerase regulatory protein Est3 is required for telomere maintenance in vivo, and shares intriguing structural and functional similarities with the mammalian telomeric protein TPP1. Here we report our physical and functional characterizations of Est3 homologues from Candida parapsilosis and Lodderomyces elongisporus, which bear unique N-and C-terminal tails in addition to a conserved central OB fold. We show that these Est3 homologues form stable complexes with the TEN domain of telomerase reverse transcriptase. Efficient complex formation requires both the N-and C-terminal tails, as well as conserved OB fold residues of Est3. Other Est3 homologues devoid of the tails failed to interact strongly with the cognate TEN domains. Remarkably, the C. parapsilosis Est3 alone exhibits no appreciable DNA-binding activity, but can be crosslinked to telomeric DNA in the presence of the TEN domain. A conserved basic residue on the putative DNAbinding surface of CpEst3 is required for efficient crosslinking. Mutating the equivalent residue in Candida albicans Est3 caused telomere attrition. We propose that interaction with the TEN domain unmasks a functionally important nucleic acid-binding activity in Est3. Our findings provide insights on the mechanisms and evolution of a widely conserved and functionally critical telomeric/ telomerase component.

show abstract

Section: Resultscontrasting

confidence: 46%

“…The history for this process is in all likelihood difficult to reconstruct (18). Nevertheless, it appears that similarly drastic changes have transpired in other telomeric proteins (e.g., plant POT1), thus highlighting the malleability of the telomere maintenance machinery in some eukaryotes (23,29).…”

Section: Discussionmentioning

confidence: 99%

Telomerase regulatory subunit Est3 in two Candida species physically interacts with the TEN domain of TERT and telomeric DNA

Yen

Chico

Lei

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…Furthermore, it is suggested in this study that a network of low-affinity interactions among multiple telomerase components is required for the proper assembly of the telomerase holoenzyme. Although S. cerevisiae Est3 has not been shown to bind directly to TLC1, it was shown to be capable of binding RNA (20). Our results are consistent with a scenario in which the telomerase proteins interact with each other and with TER1.…”

Section: Fig 6 Est3 and Reg2 Are Dispensable For Telomerase Activitsupporting

confidence: 86%

The 5′ Arm of Kluyveromyces lactis Telomerase RNA Is Critical for Telomerase Function

Kabaha

Zhitomirsky

Schwartz

et al. 2008

Molecular and Cellular Biology

View full text Add to dashboard Cite

Telomerase is a ribonucleoprotein reverse transcriptase that copies a short template within its integral telomerase RNA moiety (TER) onto eukaryotic chromosome ends, thus compensating for incomplete replication and degradation. The highly divergent yeast TER is structured in three long arms, with a catalytic core at its center. A binding site for the protein Ku80 is conserved within the 5' arm of TER in Saccharomyces but not in Kluyveromyces budding yeast species. Consistently, KU80 deletion in Kluyveromyces lactis does not affect telomere length, while it causes telomere shortening in Saccharomyces cerevisiae. We found elements in the 5' arm of K. lactis TER that are crucial for telomerase activity and stability. However, we found no indication of the association of Ku80 with this arm. Although the overexpression of Ku80 rescues a particular mutation in K. lactis TER1 that phenocopies a telomerase null mutation, this effect is indirect, caused by the repression of the recombination pathway competing for telomere maintenance. Interestingly, the overexpression of Est3, an essential telomerase protein whose function is still unknown, suppresses the phenotypes of mutations in this arm. These results indicate that the 5' arm of K. lactis TER has critical roles in telomerase function, which may be linked to the function of Est3.

show abstract

“…This possibility was raised by a prior study which reported that an S. cerevisiae GST-Est3 fusion protein, when expressed in E. coli and affinity purified, exhibited an apparent (albeit weak) ability to bind telomeric DNA substrates, as assessed by gel shifts (36). We re-examined this, using NMR chemical shift perturbation, which should reveal chemical shift changes at proximal amide sites, as well as any sites that undergo a conformational change, upon binding of DNA.…”

Section: Resultsmentioning

confidence: 99%

Investigating the role of the Est3 protein in yeast telomere replication

Lee

Mandell

Rao

et al. 2010

Nucleic Acids Research

View full text Add to dashboard Cite

The Est3 subunit of yeast telomerase, which adopts a predicted OB-fold, is essential for telomere replication. To assess the possible contributions that Est3 might make to enzyme catalysis, we compared telomerase activity from wild type and est3-Δ strains of Saccharomyces castellii, which revealed that loss of the Est3 subunit results in a 2- to 3-fold decline in nucleotide addition. This effect was not primer-specific, based on assessment of a panel of primers that spanned the template of the S. castellii telomerase RNA. Furthermore, using nuclear magnetic resonance chemical shift perturbation, no chemical shift change was observed at any site in the protein upon addition of single-stranded DNA, arguing against a role for Est3 in recognition of telomeric substrates by telomerase. Addition of exogenous Est3 protein, including mutant Est3 proteins that are severely impaired for telomere replication in vivo, fully restored activity in est3-Δ telomerase reactions. Thus, Est3 performs an in vivo regulatory function in telomere replication, which is distinct from any potential contribution that Est3 might make to telomerase activity.

show abstract

Saccharomyces cerevisiae telomerase subunit Est3p binds DNA and RNA and stimulates unwinding of RNA/DNA heteroduplexes

Cited by 11 publications

References 28 publications

Telomerase regulatory subunit Est3 in two Candida species physically interacts with the TEN domain of TERT and telomeric DNA

Telomerase regulatory subunit Est3 in two Candida species physically interacts with the TEN domain of TERT and telomeric DNA

The 5′ Arm of Kluyveromyces lactis Telomerase RNA Is Critical for Telomerase Function

Investigating the role of the Est3 protein in yeast telomere replication

Contact Info

Product

Resources

About