Journal of Zhejiang University SCIENCE B
(ISSN 1673-1581, Monthly)

2005   Vol. 6   No. 12   p. 1141-1147

            [ Home Page ] | [ PDF Full Text ]   On-line Access Date:   Nov. 22, 2005

Study on the expression and mutation of human telomeric repeat binding factor (hTRF1) in 10 malignant hematopoietic cell lines

Sun Jie, Huang He†‡, Zhu Yuan-yuan, Lan Jian-ping, Li Jing-yuan, Lai Xiao-yu, Yu Jian

(Department of Hematology, First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China)
 ‡ Corresponding Author
†E-mail: hehuangyu@126.com
Received Mar. 22, 2005 revision accepted July 4, 2005

Abstract: Objective: Detecting the expression and mutation of human telomeric repeat binding factor (hTRF1) in 10 malignant hematopoietic cell line cells on the base of determining its genomic structure and its four pseudogenes to clarify if hTRF1 mutation is one of the factors of the activation of telomerase. Methods: hTRF1cDNA sequences were obtained from GenBank, its genome structure and pseudogenes were forecasted by BLAST and other biology information programs and then testified by sequencing. Real-time RT-PCR was used to detect the expression of hTRF1mRNA in 10 cell line cells, including myelogenous leukemia cell lines K562, HL-60, U-937, NB4, THP-1, HEL and Dami; lymphoblastic leukemia cell lines 6T-CEM, Jurkat and Raji. Telomerase activities of cells were detected by using telomeric repeat amplification (TRAP)-ELISA protocol. PCR and sequencing were used to detect mutation of each exon of hTRF1 in 10 cell line cells. Results: hTRF1 gene, mapped to 8q13, was divided into 10 exons and spans 38.6 kb. Four processed pseudogenes of hTRF1 located on chromosome 13, 18, 21 and X respectively, was named as ΨhTRF1-13, ΨhTRF1-18, ΨhTRF1-21 and ΨhTRF1-X respectively. All cell line cells showed positive telomerase activity. The expression of hTRF1 was significantly lower in malignant hematopoietic cell lines cells (0.0338, 0.0108~0.0749) than in normal mononuclear cells (0.0493, 0.0369~0.128) (P=0.004). But no significant mutation was found in all exons of hTRF1 in 10 cell line cells. Four variants were found in part of intron 1, 2 and 8 of hTRF1. Their infection on gene function is unknown and needs further studies. Conclusion: hTRF1 mutation is probably not one of the main factors for telomerase activation in malignant hematopoietic disease.

Key words: Human telomeric repeat binding factor (hTRF1), Expression, Mutation, Genome, Processed pseudogene
doi:10.1631/jzus.2005.B1141             CLC number: R394

References:

[1] Aragona, M., Buda, C.A., Panetta, S., Morelli, M., Giudice, A., Campagna, F.L., Pontoriero, A., Cascinu, S., La Torre, F., 2000. Immunohistochemical telomeric-repeat binding factor-1 expression in gastrointestinal tumors. Oncol. Rep., 7(5):987-990.

[2] Chen, Y., Liu-Stratton, Y., Hassanain, H., Cool, D.R., Morris, M., 2004. Dietary sodium regulates angiotensin AT1a and AT1b mRNA expression in mouse brain. Exp. Neurol., 188(2):238-245.

[3] Chong, L., van Steensel, B., Broccoli, D., Erdjument-Bromage, H., Hanish, J., Tempst, P., de Lange, T., 1995. A human telomeric protein. Science, 270(5242):1663-1667.

[4] Kishi, S., Wulf, G., Nakamura, M., Lu, K.P., 2001. Telomeric protein Pin2/hTRF1 induces mitotic entry and apoptosis in cells with short telomeres and is down-regulated in human breast tumors. Oncogene, 20(12):1497-1508.

[5] Kyo, S., Takakura, M., Taira, T., Kanaya, T., Itoh, H., Yutsudo, M., Ariga, H., Inoue, M., 2000. Sp1 cooperates with c-Myc to activate transcription of the human telomerase reverse transcriptase gene (hTERT). Nucleic. Acids Res., 28(3):669-677.

[6] Ohyashiki, J.H., Hayashi, S., Yahata, N., Iwama, H., Ando, K., Tauchi, T., Ohyashiki, K., 2001. Impaired telomere regulation mechanism by TRF1 (telomere-binding protein), but not TRF2 expression, in acute leukemia cells. Int. J. Oncol., 18(3):593-598.

[7] Smith, S., Giriat, I., Schmitt, A., de Lange, T., 1998. Tankyrase, a poly(ADP-ribose) polymerase at human telomeres. Science, 282(5393):1484-1487.

[8] van Steensel, B., de Lange, T., 1997. Control of telomere length by the human telomeric protein hTRF1. Nature, 385(6618):740-743.

[9] Vanin, E.F., 1985. Processed pseudogenes: characteristics and evolution. Annu. Rev. Genet., 19:253-272.

[10] Yamada, K., Yagihashi, A., Yamada, M., Asanuma, K., Moriai, R., Kobayashi, D., Tsuji, N., Watanabe, N., 2002. Decreased gene expression for telomeric-repeat binding factors and TIN2 in malignant hematopoietic cells. Anticancer Res., 22(2B):1315-1320.

[11] Young, A.C., Chavez, M., Giambernardi, T.A., Mattern, V., McGill, J.R., Harris, J.M., Sarosdy, M.F., Patel, P., Sakaguchi, A.Y., 1997. Organization and expression of human telomere repeat binding factor genes. Somat. Cell Mol. Genet., 23(4):275-286.

[12] Zhou, X.Z., Lu, K.P., 2001. The Pin2/TERF1-interacting protein pinx1 is a potent telomerase inhibitor. Cell, 107(3):347-359.