Telomere maintenance and telomerase activity are differentially regulated in asexual and sexual worms
Open accessAbstract
In most sexually reproducing animals, replication and maintenance of telomeres occurs in the germ line and during early development in embryogenesis through the use of telomerase. Somatic cells generally do not maintain telomere sequences, and these cells become senescent in adults as telomeres shorten to a critical length. Some animals reproduce clonally and must therefore require adult somatic mechanisms for maintaining their chromosome ends. Here we study the telomere biology of planarian flatworms with apparently limitless regenerative capacity fueled by a population of highly proliferative adult stem cells. We show that somatic telomere maintenance is different in asexual and sexual animals. Asexual animals maintain telomere length somatically during reproduction by fission or when regeneration is induced by amputation, whereas sexual animals only achieve telomere elongation through sexual reproduction. We demonstrate that this difference is reflected in the expression and alternate splicing of the protein subunit of the telomerase enzyme. Asexual adult planarian stem cells appear to maintain telomere length over evolutionary timescales without passage through a germ-line stage. The adaptations we observe demonstrate indefinite somatic telomerase activity in proliferating stem cells during regeneration or reproduction by fission, and establish planarians as a pertinent model for studying telomere structure, function, and maintenance.
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Planarians can regenerate an entire individual from small fragments of almost any tissue.
“For planarians, small fragments of almost any tissue can be regenerated into an entire individual.”
From Inflammation and aging: signaling pathways and intervention therapies (2023) · cites this paper as [312]
The Results report that asexual planarians regenerate missing structures after fission and that sexual planarians have similar regenerative abilities. The paper supports regeneration from pieces, but the passages do not establish that small fragments of almost any tissue can become an entire individual. (LLM, conf=0.84)
Experimental — accuracy not yet measuredPlanarians overcome telomere shortening during cell division by upregulating telomerase expression during regeneration.
“The shortening of telomeres during cell division is a major obstacle to infinite cell division, and planarians overcome this problem by upregulating telomerase expression during regeneration.312”
From Inflammation and aging: signaling pathways and intervention therapies (2023) · cites this paper as [312]
The Results report that telomerase activity increases during regeneration and maintains telomere length in asexual planarians. But the paper distinguishes sexual planarians: their smaller increase in activity does not prevent telomere shortening during regeneration. The claim omits this limitation and applies the mechanism to planarians generally. (LLM, conf=0.90)
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Inflammation and aging: signaling pathways and intervention therapies
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“The shortening of telomeres during cell division is a major obstacle to infinite cell division, and planarians overcome this problem by upregulating telomerase expression during regeneration.(312) On the other hand, planarians also achieve resistance to tumors through a variety of means, such as efficient DNA repair m…”
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- Authors
- Tan, T. C. J., Rahman, R., Jaber-Hijazi, F., Felix, D. A., Chen, C., Louis, E. J., & Aboobaker, A.
- Affiliations
- University of Nottingham (GB)
- Centre for Genetics and Genomics and
- Venue
- Proceedings of the National Academy of Sciences
- Publisher
- National Academy of Sciences
- Published
- 2012-02-27
- Volume
- 109
- Issue
- 11
- Pages
- 4209-4214
- ISSN
- 0027-8424 (ISSN-L)
- 1091-6490
- PMC
- PMC3306686
- OpenAlex
- W2020595510
- Cited by
- 124
- References
- 44
- Citations by year
- 2026: 4 · 2025: 3 · 2024: 3 · 2023: 8 · 2022: 11 · 2021: 9 · 2020: 20 · 2019: 10 · 2018: 10 · 2017: 13 · 2016: 3 · 2015: 9 · 2014: 9 · 2013: 6 · 2012: 6
- FWCI
- 6.43
- Type
- journal article
- Language
- en
- Open access
- green
- www.ncbi.nlm.nih.gov
- Locations
- Proceedings of the National Academy of Sciences (publishedVersion)
- Europe PMC (PubMed Central) (publishedVersion)
- PubMed Central (publishedVersion)
- PubMed (publishedVersion)
- ENLIGHTEN (Jurnal Bimbingan dan Konseling Islam) (acceptedVersion)
- Repository@Nottingham (University of Nottingham) (submittedVersion, cc-by)
- Nottingham ePrints (University of Nottingham) (submittedVersion, cc-by)
- Funders
- Biotechnology and Biological Sciences Research Council (BB/E01030X/1)
- Topics
- Health Sciences › Medicine › Physiology › Telomeres, Telomerase, and Senescence
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Planarian Biology and Electrostimulation
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Aging › Genetics, Aging, and Longevity in Model Organisms
- Keywords
- telomere maintenance, telomerase, planarian flatworms, asexual reproduction, sexual reproduction, adult stem cells, regeneration, alternative splicing, telomerase reverse transcriptase, germline, telomere length, clonal reproduction
- MeSH terms
- Animals, Gene Expression Regulation, Germ Cells, Molecular Sequence Data, Planarians, Regeneration, Reproduction, Asexual, RNA, Messenger, Stem Cells, Telomere, Alternative Splicing, In Situ Hybridization, Telomerase, RNA Interference, Telomere Homeostasis
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