Telomeresplay a vital role in DNA repair activities and protecting chromosomes from degradation[1]. Telomeres are shortened during each cell division because of the end replication problem. After several cell division, telomeres are shortened to a critical length (< 3 kb), and eventually lead to overall genomic instability and triggering the DNA damage response[2-3], which is related to the cancerization of numerous cancers. The commonly used method to estimate telomere length isterminal restriction fragment (TRF) basedon southern blot, which requires thousands of cells and provides only a crude estimate of the average telomere length of all cells analyzed. However, it is believed that the frequency of critically short telomeres, rather than the mean telomere length, is a crucial factor for telomere dysfunction. Therefore, analysis of telomere length at the single-chromosome level is necessary to determine the frequency of critically short telomeres.
Here, we describe the development of a high-throughput method for telomere length analysis at the single-chromosome level by using a laboratory-built high-sensitivity flow cytometer (HSFCM)[4] combined with targeted fluorescent peptide nucleic acid (PNA) probes. The unambiguous detection of the telomere signalsfrom a single chromosome was achieved via HSFCM analysis. The fluorescence intensity of single chromosome was converted to the probe number by a calibration curve, and was further transformed to the base pair number of the telomere. Five representative cell lines were analyzed to compare their telomere length and the ratio of critically short telomeres at the single-chromosome level. The potential of using frequency of short telomere for disease treatment monitoring is examined by analyzing the telomere length in lymphocyte of leukemia patients. The abundance of short telomeres was compared between healthy donors and patients with chronic myeloid leukemia (CML) to see whether it can be used to predict the efficacy of therapeutics. Moreover, the quantity of short telomeres was compared among patients with acute leukemia, patients in different phases of CML and healthy donors to see whether it can be used as a marker for disease progression prediction in CML.
Reference
[1] Blackburn E. H., Epel E. S., Lin J., Science,2015, 350, 1193-1198.
[2]Collado M., Blasco M. A., Serrano M., Cell, 2007, 130, 223-233.
[3] Deng Y., Chan S. S., Chang S., Nat. Rev. Cancer, 2008, 8, 450-458.
[4] Yang LL, Zhu SB, Hang W, Wu LN, Yan XM, Anal. Chem., 2009, 81, 2555-2563.
Figure 1
Disclosures
No relevant conflicts of interest to declare.
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