Protection of Telomeres 1 Is Required for Telomere Integrity in the Moss <i>Physcomitrella patens</i>

Shakirov, Eugene V.; Perroud, Pierre‐François; Nelson, Andrew D. L.; Cannell, Maren E.; Quatrano, Ralph S.; Shippen, Dorothy E.

doi:10.1105/tpc.110.075846

Cited by 31 publications

(18 citation statements)

References 69 publications

(114 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…POT1 from algae, moss, maize, and Asparagales binds telomeric DNA in vitro (10,45). Moreover, moss POT1, like its counterparts in yeast and vertebrates, is required for chromosome end protection (45).…”

Section: Discussionmentioning

confidence: 99%

Two RNA subunits and POT1a are components of Arabidopsis telomerase

Cifuentes-Rojas

Kannan

Tseng

et al. 2010

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

Self Cite

100

View full text Add to dashboard Cite

Telomerase is a ribonucleoprotein (RNP) reverse transcriptase whose essential RNA subunit (TER) functions as a template for telomere repeat synthesis. Here we report the identification of two divergent TER moieties in the flowering plant Arabidopsis thaliana. Although both TER1 and TER2 copurify with telomerase activity and serve as templates for telomerase in vitro, depletion of TER1, but not TER2, leads to decreased telomerase activity and progressive telomere shortening in vivo. Moreover, mutation of the templating domain in TER1 results in the incorporation of mutant telomere repeats on chromosome ends. Thus, TER1 provides the major template for telomerase in vivo. We also show that POT1a binds TER1 with a Kd of 2 × 10 −7 M and the two components assemble into an enzymatically active RNP in vivo. In contrast, TER1-POT1b and TER2-POT1a associations were not observed. In other organisms POT1 proteins bind telomeric DNA and provide chromosome end protection. We propose that duplication of TER and POT1 in Arabidopsis fueled the evolution of novel proteinnucleic acid interactions and the migration of POT1 from the telomere to the telomerase RNP.OB fold | RNA template | gene duplication

show abstract

Section: Discussionmentioning

confidence: 99%

Two RNA subunits and POT1a are components of Arabidopsis telomerase

Cifuentes-Rojas

Kannan

Tseng

et al. 2010

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

Self Cite

100

View full text Add to dashboard Cite

show abstract

“…POT1, on the other hand, is highly conserved in plants, and like its vertebrate counterparts, it is crucial for chromosome end protection in the moss Physcomitrella patens (Shakirov et al 2010). Intriguingly, A. thaliana encodes two full-length POT1 proteins (POT1a and POT1b) as well as a smaller, truncated POT1 (POT1c) (Rossignol et al 2007).…”

Section: Discussionmentioning

confidence: 99%

“…None of the three AtPOT1 paralogs specifically bind telomeric DNA in vitro (Shakirov et al 2005, 2010). This phenomenon is not a quirk of Arabidopsis , because biochemical analysis of POT1 proteins across the plant kingdom revealed only two examples of DNA binding by one of two POT1 paralogs from Zea mays and the single POT1 protein from green algae (Shakirov et al 2009a,b).…”

Section: Discussionmentioning

confidence: 99%

Surprises from the Chromosome Front: Lessons from Arabidopsis on Telomeres and Telomerase

Nelson

Shippen

2012

Cold Spring Harbor Symposia on Quantitative Biology

View full text Add to dashboard Cite

Telomeres serve two vital functions: They act as a buffer against the end-replication problem, and they prevent chromosome ends from being recognized as double-strand DNA (dsDNA) breaks. These functions are orchestrated by the telomerase reverse transcriptase and a variety of telomere protein complexes. Here, we discuss our recent studies with Arabidopsis thaliana that uncovered a new and highly conserved telomere complex called CST (Cdc13/CTC1, STN1, TEN1). Formerly believed to be yeast specific, CST has now been identified as a key component of both plant and vertebrate telomeres, which is essential for genome integrity and stem cell viability. We also describe the unexpected discovery of alternative telomerase ribonucleoprotein complexes in Arabidopsis. Fueled by duplication and diversification of the telomerase RNA subunit and telomerase accessory proteins, these telomerase complexes act in concert to maintain genome stability. In addition to the canonical telomerase enzyme, one of two alternative telomerase ribonucleoprotein (RNP) complexes functions as a novel negative regulator of enzyme activity in response to genotoxic stress. These contributions highlight the immense potential of Arabidopsis in probing the depths of the chromosome end.

show abstract

“…It should be noted that the reduced colony size of the gene replacement moss lines could be due to improper RNA processing, since the vector used for gene replacement lacks a terminator sequence for the introduced PpPDK1 gene. However, this vector has been used previously for gene replacement without noticeable differences from the wild type (Shakirov et al, 2010;Spinner et al, 2010). Additionally, from the pdk1 knockout line, it appears that the loss of PpPDK1 is not completely lethal but does not produce healthy moss tissue.…”

Section: Q106amentioning

confidence: 99%

Characterization of a PDK1 Homologue from the Moss Physcomitrella patens

Dittrich

Devarenne

2011

Plant Physiology

View full text Add to dashboard Cite

The serine/threonine protein kinase 3-phosphoinositide-dependent protein kinase 1 (PDK1) is a highly conserved eukaryotic kinase that is a central regulator of many AGC kinase subfamily members. Through its regulation of AGC kinases, PDK1 controls many basic cellular processes, from translation to cell survival. While many of these PDK1-regulated processes are conserved across kingdoms, it is not well understood how PDK1 may have evolved within kingdoms. In order to better understand PDK1 evolution within plants, we have isolated and characterized the PDK1 gene from the moss Physcomitrella patens (PpPDK1), a nonvascular representative of early land plants. PpPDK1 is similar to other plant PDK1s in that it can functionally complement a yeast PDK1 knockout line. However, unlike PDK1 from other plants, the P. patens PDK1 protein does not bind phospholipids due to a lack of the lipid-binding pleckstrin homology domain, which is used for lipid-mediated regulation of PDK1 activity. Sequence analysis of several PDK1 proteins suggests that lipid regulation of PDK1 may not commonly occur in algae and nonvascular land plants. PpPDK1 can phosphorylate AGC kinase substrates from tomato (Solanum lycopersicum) and P. patens at the predicted PDK1 phosphorylation site, indicating that the PpPDK1 substrate phosphorylation site is conserved with higher plants. We have also identified residues within the PpPDK1 kinase domain that affect kinase activity and show that a mutant with highly reduced kinase activity can still confer cell viability in both yeast and P. patens. These studies lay the foundation for further analysis of the evolution of PDK1 within plants.

show abstract

Protection of Telomeres 1 Is Required for Telomere Integrity in the Moss Physcomitrella patens

Cited by 31 publications

References 69 publications

Two RNA subunits and POT1a are components of Arabidopsis telomerase

Two RNA subunits and POT1a are components of Arabidopsis telomerase

Surprises from the Chromosome Front: Lessons from Arabidopsis on Telomeres and Telomerase

Characterization of a PDK1 Homologue from the Moss Physcomitrella patens

Contact Info

Product

Resources

About