Faculty Appointments
Vice Chair of Biological SciencesVice Chair of Biological Sciences Professor of Biological Sciences
Education
Ph.D., Genetics, University of Washington, Seattle, WashingtonB.A., Biology, Carleton College, Northfield, Minnesota
Office Address
Station B Box 351634
Nashville, TN 37235-1634
Nashville, TN 37235-1634
Research Description
Our laboratory is interested in mechanisms that maintain genome stability, with research endeavors that lie at the intersection of DNA replication and DNA repair.
The Friedman lab is actively recruiting rotation students! Please contact Dr. Friedman for more information.
Genome integrity is fundamentally important for human health as mutations can lead to cancer and inherited disease. Mutation frequency is not uniform across the genome as some DNA sequences present a high risk of damage or engage at increased frequency with error-prone repair pathways. Interstitial telomere-like sequences fall into the latter category by stimulating the formation of a new, or de novo, telomere at a double-strand break (DSB). Telomeres, the repetitive, protein-bound DNA sequences at chromosome ends, promote genome stability by protecting linear chromosomes from degradation and facilitating replication through recruitment of telomerase. In contrast, addition of a de novo telomere at an internal site precludes normal repair and causes loss of all sequences distal to the break. The consequences of de novo telomere addition (dnTA) are evident in diseases such as Phelan McDermid syndrome and alpha-thalassemia where the occurrence of multiple independent mutations is consistent with presence of a destabilizing DNA sequence.
Our prior work characterized hotspots of dnTA in the yeast genome termed SiRTAs (Sites of Repair-associated Telomere Addition). SiRTAs stimulate dnTA events even when the initiating DSB is located several kilobases distal to the eventual site of telomere addition, demonstrating that SiRTAs are destabilizing due to their engagement of telomerase, rather than intrinsic fragility. We recently identified UBP10, encoding a ubiquitin protease, as a positive regulator of dnTA. Upon closer inspection, we find that nonreciprocal translocations dramatically increase at SiRTAs in the mutant background. This novel and unanticipated result implies that SiRTAs engage multiple error-prone repair pathways and that repair pathway choice is modulated by ubiquitin. Intriguingly, SiRTAs are disproportionately impacted by the loss of UBP10 and translocations formed at SiRTAs predominantly involve the subtelomeric repeats. These events resemble those facilitating survival of cancer cells in the absence of telomerase [a recombination-mediated pathway termed alternative lengthening of telomeres (ALT)]. We are leveraging these unique observations to understand how intrinsically destabilizing sequences impact genome stability and to explore the mechanisms and regulation of error-prone DNA repair.
The Friedman lab is actively recruiting rotation students! Please contact Dr. Friedman for more information.
Genome integrity is fundamentally important for human health as mutations can lead to cancer and inherited disease. Mutation frequency is not uniform across the genome as some DNA sequences present a high risk of damage or engage at increased frequency with error-prone repair pathways. Interstitial telomere-like sequences fall into the latter category by stimulating the formation of a new, or de novo, telomere at a double-strand break (DSB). Telomeres, the repetitive, protein-bound DNA sequences at chromosome ends, promote genome stability by protecting linear chromosomes from degradation and facilitating replication through recruitment of telomerase. In contrast, addition of a de novo telomere at an internal site precludes normal repair and causes loss of all sequences distal to the break. The consequences of de novo telomere addition (dnTA) are evident in diseases such as Phelan McDermid syndrome and alpha-thalassemia where the occurrence of multiple independent mutations is consistent with presence of a destabilizing DNA sequence.
Our prior work characterized hotspots of dnTA in the yeast genome termed SiRTAs (Sites of Repair-associated Telomere Addition). SiRTAs stimulate dnTA events even when the initiating DSB is located several kilobases distal to the eventual site of telomere addition, demonstrating that SiRTAs are destabilizing due to their engagement of telomerase, rather than intrinsic fragility. We recently identified UBP10, encoding a ubiquitin protease, as a positive regulator of dnTA. Upon closer inspection, we find that nonreciprocal translocations dramatically increase at SiRTAs in the mutant background. This novel and unanticipated result implies that SiRTAs engage multiple error-prone repair pathways and that repair pathway choice is modulated by ubiquitin. Intriguingly, SiRTAs are disproportionately impacted by the loss of UBP10 and translocations formed at SiRTAs predominantly involve the subtelomeric repeats. These events resemble those facilitating survival of cancer cells in the absence of telomerase [a recombination-mediated pathway termed alternative lengthening of telomeres (ALT)]. We are leveraging these unique observations to understand how intrinsically destabilizing sequences impact genome stability and to explore the mechanisms and regulation of error-prone DNA repair.
Research Keywords
Telomeres, telomerase, DNA repair, double-strand breaks, genome maintenance, genetics, cancer, genome stability, genome, molecular biology
Publications
Gonzalez DI, Westerbeek AR, Epum EA, Friedman KL. The ubiquitin protease Ubp10 suppresses the formation of translocations at interstitial telomere-like sites. Nucleic Acids Res. 2025 Nov 11/26/2025; 53(22): PMID: 41404807, PMCID: PMC12709191, PII: 8382377, DOI: 10.1093/nar/gkaf1373, ISSN: 1362-4962.
Clements KA, Vallone KT, Clements TP, Catania EH, Claiborne LL, Friedman KL, Graham TR, Johnson HJ, Starko SR, Todd TD, Watkins J, Brame CJ. Impacts of Learning Assistants on Student Belonging and Confidence Vary Across Science Disciplines and Course Contexts. CBE Life Sci Educ. 2025 Jun 6/1/2025; 24(2): ar26. PMID: 40215463, PMCID: PMC12286625, DOI: 10.1187/cbe.24-07-0179, ISSN: 1931-7913.
Clements KA, Zepeda CD, Leich Hilbun A, Todd T, Clements TP, Johnson HJ, Watkins J, Friedman KL, Brame CJ. "They Have Shown Me It Is Possible to Thrive within STEM": Incorporating Learning Assistants in General Chemistry Enhances Student Belonging and Confidence. J Chem Educ. 2023 Nov 11/14/2023; 100(11): 4200-11. PMID: 37982080, PMCID: PMC10653077, DOI: 10.1021/acs.jchemed.2c01224, ISSN: 0021-9584.
Ngo K, Gittens TH, Gonzalez DI, Hatmaker EA, Plotkin S, Engle M, Friedman GA, Goldin M, Hoerr RE, Eichman BF, Rokas A, Benton ML, Friedman KL. A comprehensive map of hotspots of de novo telomere addition in Saccharomyces cerevisiae. Genetics. 2023 May 5/26/2023; 224(2): PMID: 37119805, PMCID: PMC10474931, PII: 7147207, DOI: 10.1093/genetics/iyad076, ISSN: 1943-2631.
Hoerr RE, Eng A, Payen C, Di Rienzi SC, Raghuraman MK, Dunham MJ, Brewer BJ, Friedman KL. Hotspot of de novo telomere addition stabilizes linear amplicons in yeast grown in sulfate-limiting conditions. Genetics. 2023 May 5/26/2023; 224(2): PMID: 36702776, PMCID: PMC10213492, PII: 7005643, DOI: 10.1093/genetics/iyad010, ISSN: 1943-2631.
Clements TP, Friedman KL, Johnson HJ, Meier CJ, Watkins J, Brockman AJ, Brame CJ. "It made me feel like a bigger part of the STEM community": Incorporation of Learning Assistants Enhances Students' Sense of Belonging in a Large Introductory Biology Course. CBE Life Sci Educ. 2022 Jun; 21(2): ar26. PMID: 35412327, PMCID: PMC9508922, DOI: 10.1187/cbe.21-09-0287, ISSN: 1931-7913.
Hoerr RE, Ngo K, Friedman KL. When the Ends Justify the Means: Regulation of Telomere Addition at Double-Strand Breaks in Yeast. Front Cell Dev Biol. 2021; 9: 655377. PMID: 33816507, PMCID: PMC8012806, DOI: 10.3389/fcell.2021.655377, ISSN: 2296-634X.
Ngo K, Epum EA, Friedman KL. Emerging non-canonical roles for the Rad51-Rad52 interaction in response to double-strand breaks in yeast. Curr Genet [print-electronic]. 2020 Oct; 66(5): 917-26. PMID: 32399607, PMCID: PMC7492393, PII: 10.1007/s00294-020-01081-z, DOI: 10.1007/s00294-020-01081-z, ISSN: 1432-0983.
Epum EA, Mohan MJ, Ruppe NP, Friedman KL. Interaction of yeast Rad51 and Rad52 relieves Rad52-mediated inhibition of de novo telomere addition. PLoS Genet. 2020 Feb; 16(2): e1008608. PMID: 32012161, PMCID: PMC7018233, PII: PGENETICS-D-19-01318, DOI: 10.1371/journal.pgen.1008608, ISSN: 1553-7404.
O'Brien E, Salay LE, Epum EA, Friedman KL, Chazin WJ, Barton JK. Yeast require redox switching in DNA primase. Proc. Natl. Acad. Sci. U.S.A [print-electronic]. 2018 Dec 12/26/2018; 115(52): 13186-91. PMID: 30541886, PMCID: PMC6310810, PII: 1810715115, DOI: 10.1073/pnas.1810715115, ISSN: 1091-6490.
Schaller MD, McDowell G, Porter A, Shippen D, Friedman KL, Gentry MS, Serio TR, Sundquist WI. What's in a name?. Elife. 2017 Oct 10/24/2017; 6: PMID: 29063834, PMCID: PMC5655148, DOI: 10.7554/eLife.32437, ISSN: 2050-084X.
Obodo UC, Epum EA, Platts MH, Seloff J, Dahlson NA, Velkovsky SM, Paul SR, Friedman KL. Endogenous Hot Spots of De Novo Telomere Addition in the Yeast Genome Contain Proximal Enhancers That Bind Cdc13. Mol. Cell. Biol [electronic-print]. 2016 Jun 6/15/2016; 36(12): 1750-63. PMID: 27044869, PMCID: PMC4907100, PII: MCB.00095-16, DOI: 10.1128/MCB.00095-16, ISSN: 1098-5549.
Ning B, Feldkamp MD, Cortez D, Chazin WJ, Friedman KL, Fanning E. Simian virus Large T antigen interacts with the N-terminal domain of the 70 kD subunit of Replication Protein A in the same mode as multiple DNA damage response factors. PLoS ONE. 2015; 10(2): e0116093. PMID: 25706313, PMCID: PMC4337903, PII: PONE-D-14-45260, DOI: 10.1371/journal.pone.0116093, ISSN: 1932-6203.
Sowd GA, Mody D, Eggold J, Cortez D, Friedman KL, Fanning E. SV40 utilizes ATM kinase activity to prevent non-homologous end joining of broken viral DNA replication products. PLoS Pathog. 2014 Dec; 10(12): e1004536. PMID: 25474690, PMCID: PMC4256475, PII: PPATHOGENS-D-14-01844, DOI: 10.1371/journal.ppat.1004536, ISSN: 1553-7374.
Hawkins C, Friedman KL. Normal telomere length maintenance in Saccharomyces cerevisiae requires nuclear import of the ever shorter telomeres 1 (Est1) protein via the importin alpha pathway. Eukaryotic Cell [print-electronic]. 2014 Aug; 13(8): 1036-50. PMID: 24906415, PMCID: PMC4135794, PII: EC.00115-14, DOI: 10.1128/EC.00115-14, ISSN: 1535-9786.
Ferguson JL, Chao WC, Lee E, Friedman KL. The anaphase promoting complex contributes to the degradation of the S. cerevisiae telomerase recruitment subunit Est1p. PLoS ONE [print-electronic]. 2013; 8(1): e55055. PMID: 23372810, PMCID: PMC3555863, PII: PONE-D-12-35468, DOI: 10.1371/journal.pone.0055055, ISSN: 1932-6203.
Bairley RC, Guillaume G, Vega LR, Friedman KL. A mutation in the catalytic subunit of yeast telomerase alters primer-template alignment while promoting processivity and protein-DNA binding. J. Cell. Sci [print-electronic]. 2011 Dec 12/15/2011; 124(Pt 24): 4241-52. PMID: 22193961, PMCID: PMC4074303, PII: jcs.090761, DOI: 10.1242/jcs.090761, ISSN: 1477-9137.
Talley JM, DeZwaan DC, Maness LD, Freeman BC, Friedman KL. Stimulation of yeast telomerase activity by the ever shorter telomere 3 (Est3) subunit is dependent on direct interaction with the catalytic protein Est2. J. Biol. Chem [print-electronic]. 2011 Jul 7/29/2011; 286(30): 26431-9. PMID: 21659533, PMCID: PMC3143607, PII: M111.228635, DOI: 10.1074/jbc.M111.228635, ISSN: 1083-351X.
Friedman KL. Telomerase reverse transcriptase and Wnt signaling. Mol. Cell. Biol [print-electronic]. 2011 Jun; 31(12): 2366-8. PMID: 21536649, PMCID: PMC3133428, PII: MCB.05462-11, DOI: 10.1128/MCB.05462-11, ISSN: 1098-5549.
Osterhage JL, Friedman KL. Chromosome end maintenance by telomerase. J. Biol. Chem [print-electronic]. 2009 Jun 6/12/2009; 284(24): 16061-5. PMID: 19286666, PMCID: PMC2713563, PII: R900011200, DOI: 10.1074/jbc.R900011200, ISSN: 0021-9258.
Ji H, Adkins CJ, Cartwright BR, Friedman KL. Yeast Est2p affects telomere length by influencing association of Rap1p with telomeric chromatin. Mol. Cell. Biol [print-electronic]. 2008 Apr; 28(7): 2380-90. PMID: 18212041, PMCID: PMC2268414, PII: MCB.01648-07, DOI: 10.1128/MCB.01648-07, ISSN: 1098-5549.
Osterhage JL, Talley JM, Friedman KL. Proteasome-dependent degradation of Est1p regulates the cell cycle-restricted assembly of telomerase in Saccharomyces cerevisiae. Nat. Struct. Mol. Biol [print-electronic]. 2006 Aug; 13(8): 720-8. PMID: 16862158, PII: nsmb1125, DOI: 10.1038/nsmb1125, ISSN: 1545-9993.
Ji H, Platts MH, Dharamsi LM, Friedman KL. Regulation of telomere length by an N-terminal region of the yeast telomerase reverse transcriptase. Mol. Cell. Biol. 2005 Oct; 25(20): 9103-14. PMID: 16199886, PMCID: PMC1265764, PII: 25/20/9103, DOI: 10.1128/MCB.25.20.9103-9114.2005, ISSN: 0270-7306.
Friedman KL, Heit JJ, Long DM, Cech TR. N-terminal domain of yeast telomerase reverse transcriptase: recruitment of Est3p to the telomerase complex. Mol. Biol. Cell. 2003 Jan; 14(1): 1-13. PMID: 12529422, PMCID: PMC140223, DOI: 10.1091/mbc.E02-06-0327, ISSN: 1059-1524.
Friedman KL, Cech TR. Essential functions of amino-terminal domains in the yeast telomerase catalytic subunit revealed by selection for viable mutants. Genes Dev. 1999 Nov 11/1/1999; 13(21): 2863-74. PMID: 10557213, PMCID: PMC317136, ISSN: 0890-9369.
Clements KA, Vallone KT, Clements TP, Catania EH, Claiborne LL, Friedman KL, Graham TR, Johnson HJ, Starko SR, Todd TD, Watkins J, Brame CJ. Impacts of Learning Assistants on Student Belonging and Confidence Vary Across Science Disciplines and Course Contexts. CBE Life Sci Educ. 2025 Jun 6/1/2025; 24(2): ar26. PMID: 40215463, PMCID: PMC12286625, DOI: 10.1187/cbe.24-07-0179, ISSN: 1931-7913.
Clements KA, Zepeda CD, Leich Hilbun A, Todd T, Clements TP, Johnson HJ, Watkins J, Friedman KL, Brame CJ. "They Have Shown Me It Is Possible to Thrive within STEM": Incorporating Learning Assistants in General Chemistry Enhances Student Belonging and Confidence. J Chem Educ. 2023 Nov 11/14/2023; 100(11): 4200-11. PMID: 37982080, PMCID: PMC10653077, DOI: 10.1021/acs.jchemed.2c01224, ISSN: 0021-9584.
Ngo K, Gittens TH, Gonzalez DI, Hatmaker EA, Plotkin S, Engle M, Friedman GA, Goldin M, Hoerr RE, Eichman BF, Rokas A, Benton ML, Friedman KL. A comprehensive map of hotspots of de novo telomere addition in Saccharomyces cerevisiae. Genetics. 2023 May 5/26/2023; 224(2): PMID: 37119805, PMCID: PMC10474931, PII: 7147207, DOI: 10.1093/genetics/iyad076, ISSN: 1943-2631.
Hoerr RE, Eng A, Payen C, Di Rienzi SC, Raghuraman MK, Dunham MJ, Brewer BJ, Friedman KL. Hotspot of de novo telomere addition stabilizes linear amplicons in yeast grown in sulfate-limiting conditions. Genetics. 2023 May 5/26/2023; 224(2): PMID: 36702776, PMCID: PMC10213492, PII: 7005643, DOI: 10.1093/genetics/iyad010, ISSN: 1943-2631.
Clements TP, Friedman KL, Johnson HJ, Meier CJ, Watkins J, Brockman AJ, Brame CJ. "It made me feel like a bigger part of the STEM community": Incorporation of Learning Assistants Enhances Students' Sense of Belonging in a Large Introductory Biology Course. CBE Life Sci Educ. 2022 Jun; 21(2): ar26. PMID: 35412327, PMCID: PMC9508922, DOI: 10.1187/cbe.21-09-0287, ISSN: 1931-7913.
Hoerr RE, Ngo K, Friedman KL. When the Ends Justify the Means: Regulation of Telomere Addition at Double-Strand Breaks in Yeast. Front Cell Dev Biol. 2021; 9: 655377. PMID: 33816507, PMCID: PMC8012806, DOI: 10.3389/fcell.2021.655377, ISSN: 2296-634X.
Ngo K, Epum EA, Friedman KL. Emerging non-canonical roles for the Rad51-Rad52 interaction in response to double-strand breaks in yeast. Curr Genet [print-electronic]. 2020 Oct; 66(5): 917-26. PMID: 32399607, PMCID: PMC7492393, PII: 10.1007/s00294-020-01081-z, DOI: 10.1007/s00294-020-01081-z, ISSN: 1432-0983.
Epum EA, Mohan MJ, Ruppe NP, Friedman KL. Interaction of yeast Rad51 and Rad52 relieves Rad52-mediated inhibition of de novo telomere addition. PLoS Genet. 2020 Feb; 16(2): e1008608. PMID: 32012161, PMCID: PMC7018233, PII: PGENETICS-D-19-01318, DOI: 10.1371/journal.pgen.1008608, ISSN: 1553-7404.
O'Brien E, Salay LE, Epum EA, Friedman KL, Chazin WJ, Barton JK. Yeast require redox switching in DNA primase. Proc. Natl. Acad. Sci. U.S.A [print-electronic]. 2018 Dec 12/26/2018; 115(52): 13186-91. PMID: 30541886, PMCID: PMC6310810, PII: 1810715115, DOI: 10.1073/pnas.1810715115, ISSN: 1091-6490.
Schaller MD, McDowell G, Porter A, Shippen D, Friedman KL, Gentry MS, Serio TR, Sundquist WI. What's in a name?. Elife. 2017 Oct 10/24/2017; 6: PMID: 29063834, PMCID: PMC5655148, DOI: 10.7554/eLife.32437, ISSN: 2050-084X.
Obodo UC, Epum EA, Platts MH, Seloff J, Dahlson NA, Velkovsky SM, Paul SR, Friedman KL. Endogenous Hot Spots of De Novo Telomere Addition in the Yeast Genome Contain Proximal Enhancers That Bind Cdc13. Mol. Cell. Biol [electronic-print]. 2016 Jun 6/15/2016; 36(12): 1750-63. PMID: 27044869, PMCID: PMC4907100, PII: MCB.00095-16, DOI: 10.1128/MCB.00095-16, ISSN: 1098-5549.
Ning B, Feldkamp MD, Cortez D, Chazin WJ, Friedman KL, Fanning E. Simian virus Large T antigen interacts with the N-terminal domain of the 70 kD subunit of Replication Protein A in the same mode as multiple DNA damage response factors. PLoS ONE. 2015; 10(2): e0116093. PMID: 25706313, PMCID: PMC4337903, PII: PONE-D-14-45260, DOI: 10.1371/journal.pone.0116093, ISSN: 1932-6203.
Sowd GA, Mody D, Eggold J, Cortez D, Friedman KL, Fanning E. SV40 utilizes ATM kinase activity to prevent non-homologous end joining of broken viral DNA replication products. PLoS Pathog. 2014 Dec; 10(12): e1004536. PMID: 25474690, PMCID: PMC4256475, PII: PPATHOGENS-D-14-01844, DOI: 10.1371/journal.ppat.1004536, ISSN: 1553-7374.
Hawkins C, Friedman KL. Normal telomere length maintenance in Saccharomyces cerevisiae requires nuclear import of the ever shorter telomeres 1 (Est1) protein via the importin alpha pathway. Eukaryotic Cell [print-electronic]. 2014 Aug; 13(8): 1036-50. PMID: 24906415, PMCID: PMC4135794, PII: EC.00115-14, DOI: 10.1128/EC.00115-14, ISSN: 1535-9786.
Ferguson JL, Chao WC, Lee E, Friedman KL. The anaphase promoting complex contributes to the degradation of the S. cerevisiae telomerase recruitment subunit Est1p. PLoS ONE [print-electronic]. 2013; 8(1): e55055. PMID: 23372810, PMCID: PMC3555863, PII: PONE-D-12-35468, DOI: 10.1371/journal.pone.0055055, ISSN: 1932-6203.
Bairley RC, Guillaume G, Vega LR, Friedman KL. A mutation in the catalytic subunit of yeast telomerase alters primer-template alignment while promoting processivity and protein-DNA binding. J. Cell. Sci [print-electronic]. 2011 Dec 12/15/2011; 124(Pt 24): 4241-52. PMID: 22193961, PMCID: PMC4074303, PII: jcs.090761, DOI: 10.1242/jcs.090761, ISSN: 1477-9137.
Talley JM, DeZwaan DC, Maness LD, Freeman BC, Friedman KL. Stimulation of yeast telomerase activity by the ever shorter telomere 3 (Est3) subunit is dependent on direct interaction with the catalytic protein Est2. J. Biol. Chem [print-electronic]. 2011 Jul 7/29/2011; 286(30): 26431-9. PMID: 21659533, PMCID: PMC3143607, PII: M111.228635, DOI: 10.1074/jbc.M111.228635, ISSN: 1083-351X.
Friedman KL. Telomerase reverse transcriptase and Wnt signaling. Mol. Cell. Biol [print-electronic]. 2011 Jun; 31(12): 2366-8. PMID: 21536649, PMCID: PMC3133428, PII: MCB.05462-11, DOI: 10.1128/MCB.05462-11, ISSN: 1098-5549.
Osterhage JL, Friedman KL. Chromosome end maintenance by telomerase. J. Biol. Chem [print-electronic]. 2009 Jun 6/12/2009; 284(24): 16061-5. PMID: 19286666, PMCID: PMC2713563, PII: R900011200, DOI: 10.1074/jbc.R900011200, ISSN: 0021-9258.
Ji H, Adkins CJ, Cartwright BR, Friedman KL. Yeast Est2p affects telomere length by influencing association of Rap1p with telomeric chromatin. Mol. Cell. Biol [print-electronic]. 2008 Apr; 28(7): 2380-90. PMID: 18212041, PMCID: PMC2268414, PII: MCB.01648-07, DOI: 10.1128/MCB.01648-07, ISSN: 1098-5549.
Osterhage JL, Talley JM, Friedman KL. Proteasome-dependent degradation of Est1p regulates the cell cycle-restricted assembly of telomerase in Saccharomyces cerevisiae. Nat. Struct. Mol. Biol [print-electronic]. 2006 Aug; 13(8): 720-8. PMID: 16862158, PII: nsmb1125, DOI: 10.1038/nsmb1125, ISSN: 1545-9993.
Ji H, Platts MH, Dharamsi LM, Friedman KL. Regulation of telomere length by an N-terminal region of the yeast telomerase reverse transcriptase. Mol. Cell. Biol. 2005 Oct; 25(20): 9103-14. PMID: 16199886, PMCID: PMC1265764, PII: 25/20/9103, DOI: 10.1128/MCB.25.20.9103-9114.2005, ISSN: 0270-7306.
Friedman KL, Heit JJ, Long DM, Cech TR. N-terminal domain of yeast telomerase reverse transcriptase: recruitment of Est3p to the telomerase complex. Mol. Biol. Cell. 2003 Jan; 14(1): 1-13. PMID: 12529422, PMCID: PMC140223, DOI: 10.1091/mbc.E02-06-0327, ISSN: 1059-1524.
Friedman KL, Cech TR. Essential functions of amino-terminal domains in the yeast telomerase catalytic subunit revealed by selection for viable mutants. Genes Dev. 1999 Nov 11/1/1999; 13(21): 2863-74. PMID: 10557213, PMCID: PMC317136, ISSN: 0890-9369.