We have read with interest the article “Telomere length
regulates TERRA levels through increased trimethylation of telomeric H3K9 and HP1α” by Arnoult and
colleagues [1]. This study focuses on human telomeric chromatin structure using
different techniques like Chromatin Immunoprecipitation (ChIP),
cytolocalization or RT-qPCR. However, it has been performed without taking into
consideration the presence of Interstitial Telomeric Sequences (ITSs) in the
human genome. Some of the conclusions of the article are undoubtedly clear but
there are others that might be explained in alternative ways, considering the
existence of ITSs. Following, we mention some comments that arise from this
interesting article.
References
[1]
N. Arnoult, A. Van Beneden and A. Decottignies, “Telomere Length Regulates TERRA Levels through Increased Trimethylation of Telomeric H3K9 and HP1α,” Nature Structural & Molecular Biology, Vol. 19, 2012, pp. 948-957
[2]
M. Vega-Palas, S. Venditti and E. Di Mauro, “Telomeric Transcriptional Silencing in a Natural Context,” Nature Genetics, Vol. 15, 1997, pp. 232-233.
doi:10.1038/ng0397-232
[3]
G. Fourel, E. Revardel, C. Koering and E. Gilson, “Cohabitation of Insulators and Silencing Elements in Yeast Subtelomeric Regions,” EMBO Journal, Vol. 18, 1999, pp. 2522-2537. doi:10.1093/emboj/18.9.2522
[4]
F. Pryde and E. Louis, “Limitations of Silencing at Native Yeast Telomeres,” EMBO Journal, Vol. 18, 1999, pp. 2538-2550. doi:10.1093/emboj/18.9.2538
[5]
M. Bryk, M. Banerjee, M. Murphy, K. Knudsen, K. Garfinkel and M. Curcio, “Transcriptional Silencing of Ty1 Elements in the RDN1 Locus of Yeast,” Genes and Development, Vol. 11, 1997, pp. 255-269.
doi:10.1101/gad.11.2.255
[6]
M. Vaquero-Sedas and M. Vega-Palas, “On the Chromatin Structure of Eukaryotic Telomeres,” Epigenetics, Vol. 6, No. 9, 2011, pp. 1055-1058. doi:10.4161/epi.6.9.16845
[7]
J. Vrbsky, S. Akimcheva, J. Watson, T. Turner, L. Daxinger, B. Vyskot, W. Aufsatz and K. Riha, “siRNA-Mediated Methylation of Arabidopsis Telomeres,” PLoS Genetics, Vol. 6, No. 6, 2010, e1000986.
doi:10.1371/journal.pgen.1000986
[8]
C. Azzalin, P. Reichenbach, L. Khoriauli, E. Giulotto and J. Lingner, “Telomeric Repeat Containing RNA and RNA Surveillance Factors at Mammalian Chromosome Ends,” Science, Vol. 318, 2007, pp. 798-801.
[9]
S. Feuerhahn, N. Iglesias, A. Panza, A. Porro and J. Lingner, “TERRA Biogenesis, Turnover and Implications for Function,” FEBS Letters, Vol. 584, No. 17, 2010, pp. 3812-3818. doi:10.1016/j.febslet.2010.07.032
[10]
D. Yang, Y. Xiong, H. Kim, Q. He, Y. Li, R. Chen and Z. Songyang, “Human Telomeric Proteins Occupy Selective Interstitial Sites,” Cell Research, Vol. 21, 2011, pp. 1013-1027. doi:10.1038/cr.2011.39
[11]
T. Simonet, L. E. Zaragosi, C. Philippe, K. Lebrigand, C. Schouteden, A. Augereau, S. Bauwens, J. Ye, M. Santagostino, E. Giulotto, F. Magdinier, B. Horard, P. Barbry, R. Waldmann and E. Gilson, “The Human TTAGGG Repeat Factors 1 and 2 Bind to a Subset of Interstitial Telomeric Sequences and Satellite Repeats,” Cell Research, Vol. 21, 2011, pp. 1028-1038. doi:10.1038/cr.2011.40
[12]
M. Vaquero-Sedas, F. Gámez-Arjona and M. Vega-Palas, “Arabidopsis thaliana Telomeres Exhibit Euchromatic Features,” Nucleic Acids Research, Vol. 39, 2011, pp. 2007-2017. doi:10.1093/nar/gkq1119
[13]
M. Vaquero-Sedas, C. Luo and M. Vega-Palas, “Analysis of the Epigenetic Status of Telomeres by Using ChIP-seq Data,” Nucleic Acids Research, Vol. 40, 2012, e163.
doi:10.1093/nar/gks730
[14]
M. Vaquero-Sedas and M. Vega-Palas, “Differential Association of Arabidopsis telomeres and Centromeres with Histone H3 Variants,” Scientific Reports, Vol. 3, 2013, 1202. doi:10.1038/srep01202
[15]
M. Vega-Palas and M. Vaquero-Sedas, “Integrating Telomeres into Genome-Wide ChIP-seq Analyses,” Protocol Exchange, 2013. doi:10.1038/protex.2013.039
