Role of mammalian Rad54 in telomere length maintenance - PubMed (original) (raw)
Role of mammalian Rad54 in telomere length maintenance
Isabel Jaco et al. Mol Cell Biol. 2003 Aug.
Free PMC article
Abstract
The homologous recombination (HR) DNA repair pathway participates in telomere length maintenance in yeast but its putative role at mammalian telomeres is unknown. Mammalian Rad54 is part of the HR machinery, and Rad54-deficient mice show a reduced HR capability. Here, we show that Rad54-deficient mice also show significantly shorter telomeres than wild-type controls, indicating that Rad54 activity plays an essential role in telomere length maintenance in mammals. Rad54 deficiency also resulted in an increased frequency of end-to-end chromosome fusions involving telomeres compared to the controls, suggesting a putative role of Rad54 in telomere capping. Finally, the study of mice doubly deficient for Rad54 and DNA-PKcs showed that telomere fusions due to DNA-PKcs deficiency were not rescued in the absence of Rad54, suggesting that they are not mediated by Rad54 activity.
Figures
FIG. 1.
Telomere length analysis by Q-FISH. (A) Average telomere fluorescence and standard error of q-telomeres, p-telomeres, or all (p+q) telomeres in primary MEFs grouped by genotype. Fluorescence is expressed in telomere fluorescence units (TFUs), where 1 TFU corresponds to 1 kb of TTAGGG repeats (30). Each value represents the mean of 10 metaphases and of the indicated number (n) of individual telomere values. n refers to the total number of telomere values used for calculation of the average telomere fluorescence for each chromosome arm, as well as for the sum of both arms. Bars: ▪, average of q- and p-telomeres; , q-telomeres; □, p-telomeres. Despite the wide heterogeneity in individual telomere fluorescence intensity values (see, for example, Fig. 1B), the standard errors of the mean are very small due to the large number of datum points (see “_n_” values). As a result, the error bars are not visible in the graphs (see Table 1 for standard error values). (B) Histograms showing the telomere length frequencies for p-arms, q-arms, or the sum of p+q-arms of primary MEFs grouped by genotype. The letters indicate the individual MEFs of each genotype used for the analysis. n is the total number of p-telomeres, q-telomeres, or the sum of p+q-telomeres per genotype that are represented in each histogram. One TFU corresponds to 1 kb of TTAGGG repeats (30). To facilitate visualization of the telomere length values, two vertical lines indicate the position of the 20- and 60-kb telomeres for each histogram. The telomere length frequency distribution in each histogram is an indication of the standard deviation of telomere length values and not of the standard error. (C) Percentage of telomeres of the total number of telomeres analyzed for each genotype that are ≤20 kb or ≥60 kb, as indicated. The absolute numbers of telomeres used for the analysis are also shown on top of the bars.
FIG. 2.
Telomerase activity in MEFs. S-100 extracts were prepared from MEFs of the indicated genotype and assayed for telomerase activity. For some genotypes more than 1 MEF was assayed for TRAP activity. Different letters refer to independent MEFs. Extracts were pretreated (+R) or not with RNase. The protein concentration used is indicated. The arrow indicates the internal control (IC) for PCR efficiency.
FIG. 3.
CO-FISH primary MEFs. (Left panel) Frequency of chromosome-type or chromatid-type fusions involving telomeres produced by leading-strand synthesis in metaphases of the indicated genotypes. (+)TTAGGG, fusions showing TTAGGG signal at the fusion point; (−)TTAGGG, fusions lacking TTAGGG signal at the fusion point. (Right panels) Representative CO-FISH images of chromosome-type telomere fusions containing TTAGGG repeats at the fusion point (yellow arrows) in the indicated individual MEF. Blue, DAPI; red, TTAGGG signal.
Similar articles
- Mammalian Ku86 protein prevents telomeric fusions independently of the length of TTAGGG repeats and the G-strand overhang.
Samper E, Goytisolo FA, Slijepcevic P, van Buul PP, Blasco MA. Samper E, et al. EMBO Rep. 2000 Sep;1(3):244-52. doi: 10.1093/embo-reports/kvd051. EMBO Rep. 2000. PMID: 11256607 Free PMC article. - RAD50 and RAD51 define two pathways that collaborate to maintain telomeres in the absence of telomerase.
Le S, Moore JK, Haber JE, Greider CW. Le S, et al. Genetics. 1999 May;152(1):143-52. doi: 10.1093/genetics/152.1.143. Genetics. 1999. PMID: 10224249 Free PMC article. - Functional interaction between DNA-PKcs and telomerase in telomere length maintenance.
Espejel S, Franco S, Sgura A, Gae D, Bailey SM, Taccioli GE, Blasco MA. Espejel S, et al. EMBO J. 2002 Nov 15;21(22):6275-87. doi: 10.1093/emboj/cdf593. EMBO J. 2002. PMID: 12426399 Free PMC article. - DNA repair factors and telomere-chromosome integrity in mammalian cells.
Hande MP. Hande MP. Cytogenet Genome Res. 2004;104(1-4):116-22. doi: 10.1159/000077475. Cytogenet Genome Res. 2004. PMID: 15162024 Review. - Recombination at mammalian telomeres: an alternative mechanism for telomere protection and elongation.
Tarsounas M, West SC. Tarsounas M, et al. Cell Cycle. 2005 May;4(5):672-4. doi: 10.4161/cc.4.5.1689. Epub 2005 May 25. Cell Cycle. 2005. PMID: 15846103 Review.
Cited by
- The crosstalk between telomeres and DNA repair mechanisms: an overview to mammalian somatic cells, germ cells, and preimplantation embryos.
Tire B, Talibova G, Ozturk S. Tire B, et al. J Assist Reprod Genet. 2024 Feb;41(2):277-291. doi: 10.1007/s10815-023-03008-2. Epub 2024 Jan 2. J Assist Reprod Genet. 2024. PMID: 38165506 Review. - The multifaceted roles of DNA repair and replication proteins in aging and obesity.
D'Amico AM, Vasquez KM. D'Amico AM, et al. DNA Repair (Amst). 2021 Mar;99:103049. doi: 10.1016/j.dnarep.2021.103049. Epub 2021 Jan 21. DNA Repair (Amst). 2021. PMID: 33529944 Free PMC article. Review. - RAD54 promotes alternative lengthening of telomeres by mediating branch migration.
Mason-Osann E, Terranova K, Lupo N, Lock YJ, Carson LM, Flynn RL. Mason-Osann E, et al. EMBO Rep. 2020 Jun 4;21(6):e49495. doi: 10.15252/embr.201949495. Epub 2020 Apr 26. EMBO Rep. 2020. PMID: 32337843 Free PMC article. - Heterochromatin replication goes hand in hand with telomere protection.
Mendez-Bermudez A, Giraud-Panis MJ, Ye J, Gilson E. Mendez-Bermudez A, et al. Nat Struct Mol Biol. 2020 Apr;27(4):313-318. doi: 10.1038/s41594-020-0400-1. Epub 2020 Mar 30. Nat Struct Mol Biol. 2020. PMID: 32231287 Review. - The many facets of homologous recombination at telomeres.
Claussin C, Chang M. Claussin C, et al. Microb Cell. 2015 Jul 30;2(9):308-321. doi: 10.15698/mic2015.09.224. Microb Cell. 2015. PMID: 28357308 Free PMC article. Review.
References
- Alexander, P., and Z. B. Mikulski. 1961. Mouse lymphoma cells with different radiosensitivities. Nature 192:572-573. - PubMed
- Bailey, S. M., M. N. Conforth, A. Kurimasa, D. J. Chen, and E. H. Goodwin. 2001. Strand-specific postreplicative processing of mammalian telomeres. Science 293:2462-2465. - PubMed
- Blackburn, E. H. 2001. Switching and signaling at the telomere. Cell 106:661-673. - PubMed
- Blasco, M. A., M. Rizen, C. W. Greider, and D. Hanahan. 1996. Differential regulation of telomerase activity and telomerase RNA during multi-stage tumorigenesis. Nat. Genet. 12:200-204. - PubMed
Publication types
MeSH terms
Substances
LinkOut - more resources
Full Text Sources
Molecular Biology Databases