实验室简介：
实验室致力于研究染色体端粒DNA高级结构与生物学功能，端粒DNA复制机理，端粒结合蛋白，细胞分裂控制与细胞复制性衰老，核酸四链体（G-quadruplex）结构的形成、特性与基因表达调控。所在国家重点实验室具有先进的实验仪器设备，研究生待遇良好（硕士～2050元/月，博士～2700元/月，12个月）。
网页：http://sourcedb.ioz.cas.cn/zw/zjrc/200907/t20090716_2088456.html
网页(英文)：http://www.biomembrane.ioz.ac.cn/Entanz.asp
欢迎有意推免或报考的同学联系了解（包括毕业实习机会）。联系方式：
谭铮：电话 (10)-6480-7259，E-mail: z.tan@ioz.ac.cn或tanclswu@public.wh.hb.cn。
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实验室近五年发表论文：
1. Wang, Q., Liu, J.-q., Chen, Z., Zheng, K.-w., Chen, C.-y., Hao, Y.-h. and Tan, Z. (2011) G-quadruplex formation at the 3' end of telomere DNA inhibits its extension by telomerase, polymerase and unwinding by helicase. Nucleic Acids Res., in press.
2. Zheng, K.W., Zhang, D., Zhang, L.X., Hao, Y.H., Zhou, X. and Tan, Z. (2011) Dissecting the strand folding orientation and formation of g-quadruplexes in single- and double-stranded nucleic acids by ligand-induced photocleavage footprinting. J. Am. Chem. Soc., 133, 1475-1483.
3. Zheng, K.W., Chen, Z., Hao, Y.H. and Tan, Z. (2010) Molecular crowding creates an essential environment for the formation of stable G-quadruplexes in long double-stranded DNA. Nucleic Acids Res., 38, 327-338.
4. Liu, J.Q., Chen, C.Y., Xue, Y., Hao, Y.H. and Tan, Z. (2010) G-Quadruplex Hinders Translocation of BLM Helicase on DNA: A Real-Time Fluorescence Spectroscopic Unwinding Study and Comparison with Duplex Substrates. J. Am. Chem. Soc., 132, 10521-10527.
5. Wang, Q., Ma, L., Hao, Y.H. and Tan, Z. (2010) Folding equilibrium constants of telomere g-quadruplexes in free state or associated with proteins determined by isothermal differential hybridization. Anal. Chem., 82, 9469-9475.
6. Chen, Z., Zheng, K.W., Hao, Y.H. and Tan, Z. (2009) Reduced or Diminished Stabilization of the Telomere G-Quadruplex and Inhibition of Telomerase by Small Chemical Ligands under Molecular Crowding Condition. J. Am. Chem. Soc., 131, 10430-10438.
7. Yuan, B.F., Zhuang, X.Y., Hao, Y.H. and Tan, Z. (2008) Kinetics of base stacking-aided DNA hybridization. Chem. Commun., 6600-6602.
8. Wang, F., Zhao, Y., Hao, Y.H. and Tan, Z. (2008) Identification of low-abundance alternatively spliced mRNA variants by exon exclusive reverse transcriptase polymerase chain reaction. Anal. Biochem., 383, 307-310.
9. Tang, J., Kan, Z.Y., Yao, Y., Wang, Q., Hao, Y.H. and Tan, Z. (2008) G-quadruplex preferentially forms at the very 3' end of vertebrate telomeric DNA. Nucleic Acids Res., 36, 1200-1208.
10. Yao, Y., Wang, Q., Hao, Y.H. and Tan, Z. (2007) An exonuclease I hydrolysis assay for evaluating G-quadruplex stabilization by small molecules. Nucleic Acids Res., 35, e68.
11. Zhuang, X.Y., Tang, J., Hao, Y.H. and Tan, Z. (2007) Fast detection of quadruplex structure in DNA by the intrinsic fluorescence of a single-stranded DNA binding protein. J. Mol. Recognit., 20, 386-391.
12. Yuan, B.F., Xue, Y., Luo, M., Hao, Y.H. and Tan, Z. (2007) Two DNAzymes targeting the telomerase mRNA with large difference in Mg2+ concentration for maximal catalytic activity. Int. J. Biochem. Cell Biol., 39, 1119-1129.
13. Xue, Y., Kan, Z.Y., Wang, Q., Yao, Y., Liu, J., Hao, Y.H. and Tan, Z. (2007) Human telomeric DNA forms parallel-stranded intramolecular G-quadruplex in K+ solution under molecular crowding condition. J. Am. Chem. Soc., 129, 11185-11191.
14. Kan, Z.Y., Lin, Y., Wang, F., Zhuang, X.Y., Zhao, Y., Pang, D.W., Hao, Y.H. and Tan, Z. (2007) G-quadruplex formation in human telomeric (TTAGGG)(4) sequence with complementary strand in close vicinity under molecularly crowded condition. Nucleic Acids Res., 35, 3646-3653.
研究领域背景简介：
端粒是染色体末端的重复DNA序列，它防止细胞将天然染色体末端识别为染色体断裂，起着保护和稳定染色体的作用。在细胞分裂过程中，由于DNA的半保留复制是不完全的复制，每一次DNA复制后染色体末端要丢失一段端粒DNA序列。如果没有补偿，端粒会随着细胞分裂变得越来越短。当端粒变得太短时，细胞将失去分裂能力。端粒长度的维持是细胞持续分裂的前提条件。端粒缩短可端粒酶延伸端粒DNA而得到补偿。在生殖细胞和大多数癌细胞中，端粒酶被激活，它在端粒末端添加端粒序列，保证这些细胞中端粒长度的稳定，使细胞具有永久的分裂能力。除了经典的Double helix结构外，富G核酸，例如端粒DNA，能够折叠，通过Hoogsteen氢键形成G-quadruplex（G-四链体）结构。能够形成G-quadruplex的核酸序列在人和其它物种的基因组中已发现有几十万之多，而且它们在基因区富集，是基因表达的重要调控原件，大多与细胞生长增殖异常的疾病如癌症有重要关系。由于上述原因，富G核酸及其高级结构，特别是它所形成的G-quadruplex（G-四链体）结构正在成为生物学、医学、化学和药学界的研究热点。
