逆转座子激活对白念珠菌适应性形成的调控作用及其机制研究
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摘要
白念珠菌是人类真菌感染主要的机会致病菌之一,目前许多潜在因素包括免疫抑制剂治疗、抗生素治疗、人类免疫缺陷病毒感染以及糖尿病等导致白念珠菌感染发病率升高,而白念珠菌本身对环境高度的高适应能力更加重真菌感染的形势。逆转座子(retrotransposons)是一种可移动基因片段,可经RNA介导发生自主转座,广泛存在于多细胞的真核生物中,对真核生物的基因组结构以及遗传进化都具有重要的影响。近年来关于逆转座子的转座活性控制机制及其对宿主基因转录表达影响的研究是当前国际上生命科学领域研究的热点课题之一。本课题旨在发现白念珠菌中参与调控作用的逆转座子,并初步探讨逆转座子产生转录转座活性的可能机制,从遗传进化的角度解释白念珠菌中的逆转座子激活与其高适应性形成的关系。
     实验采用实时定量RT-PCR的方法,以白念珠菌SC5314为供试菌,考察参与损伤修复通路的基因在各种刺激条件下表达情况,并进一步比较白念珠菌基因组中逆转座子蛋白编码区ORFs的表达差异以寻找具有转录活性的逆转座子。大量文献提示逆转座子的激活与DNA损伤相关,因此首先选择直接作用于DNA分子的致癌剂MMS刺激,可引起参与损伤修复的基因,特别是参与同源重组修复的基因表达升高,并且可引起除TCA8(orf19.6078 and orf19.6079)以外的多数逆转座子ORFs发生程度不同的转录激活,提示白念珠菌中存在着有活性的逆转座子。在此基础上,我们深入地研究一些重要的环境刺激因素(高渗透、氧化刺激、唑类药物)浓度达到半数致死剂量(IC50)时对白念珠菌逆转座子蛋白编码区ORFs的转录表达影响。结果表明咪康唑(MCZ)和双氧水(H_2O_2)刺激均可引起参与DNA损伤修复的基因广泛地转录激活,并且在MCZ刺激6h时,TCA3 (ORF19.2219)、Zorro2 (ORF19.7274和ORF19.7275)以及TCA11 (ORF19.6469)发生转录激活。H_2O_2刺激6 h时能选择性地激活TCA8 (ORF19.6078和ORF19.6079)的转录活性,且在时间上修复基因优先于逆转座子产生活性。但在高渗透刺激条件下,无论是NaCl还是sorbital高渗透刺激,均未发现有活性的逆转座子,对损伤修复基因的表达影响无上调作用。由此推测环境对逆转座子表达活性的调节具有选择性,其转录激活与细胞的损伤修复密切相关。
     为进一步探讨MCZ和H_2O_2刺激激活逆转座子转录的机制,本课题在MCZ和H_2O_2刺激前给予抗氧化剂NAC,比较二者联合作用对菌株的生长、逆转座子、参与损伤修复基因的表达以及细胞内ROS水平三方面的影响。研究表明NAC与MCZ刺激联合时可抑制MCZ的杀菌作用,有效地保护酵母态细胞,而与H_2O_2联用却对菌株的生长情况无保护作用;NAC与二者联合作用均可显著地降低刺激所导致的损伤修复基因表达上调,并且刺激所激活的逆转座子表达活性也会相应的减弱或消失;荧光检测细胞内活性氧显示NAC可有效地抑制MCZ、H_2O_2刺激所导致的细胞内ROS的产生积聚。提示MCZ和H_2O_2刺激后的ROS积聚使得细胞间接发生氧化损伤,同时启动DNA损伤修复通路,调控逆转座子的表达。
     最后,我们采用southern blotting技术深入分析这些激活的逆转座子是否能够参与复制周期的所有过程,直至形成完整的双链DNA分子,进一步评估转录活化的逆转座子功能。实验首先在液体培养基中长时间的环境加压刺激诱导若干株菌,通过酶切后的基因组与特定标记的逆转座子探针杂交显色,发现MCZ诱导菌中Zorro2的拷贝片段明显增加,而TCA3的拷贝片段反而减少;H_2O_2诱导菌也显示可能发生TCA8拷贝片段的增加。随后采用微量液基稀释法及spot assay实验初步鉴定表型,发现诱导后的菌株对各自的刺激源耐受性增加。结果表明环境长期的加压刺激会导致某些逆转座子在基因组中的拷贝变化,这种基因组重塑可能通过多种方式改变宿主基因的表达,调控对环境的适应能力。因此,我们认为逆转座子在基因组水平的潜在调节作用是白念珠菌遗传进化的内在动力,而白念珠菌高适应性的形成也很有可能与其基因组中广泛分布的逆转座子的调控作用相关。
Candida albicans, the major human fungal pathogen, is capable of causing superficial to life-threatening infections. Recently, many predisposing factors, including immunosuppressive therapy, antibiotic therapy, human immunodeficiency virus infection and diabetes, cause the high rate of C.albicans infection; however the high adaptability to environment change for C. albicans cells leads to current critical infection situation. Retrotransposons are mobile genetic elements capable of autonomous transposition via RNA intermediates. They are widespread in multicellular eukaryotes, and have an important effect on the structure of eukaryotic genomic and genetic evolution. In recent years, researches about retrotansposons transposition activity mechanism and their impact on the host gene transcription are one of the hot topics on the life science in current international research. The aim for this study is to discover active retrotansposons involving in regulating host genes in C. albicans, preliminarily to investigate the possible mechanism for retrotansposons transcription and transposition activity, and finally to explain the relationship between activated retrotansposons and the high adaptive ability in C. albicans from the perspective of genetic evolution.
     In this study, real-time quantitative RT-PCR for C. albicans SC5314 was adopted to calculate the relative express quantity for genes involving in DNA damage repair parthway, meanwhile, according to the relative expression variation for retrotansposons protein encoded regions (represented by ORFs) in C. albicans genome in response to stresses, the transcriptionally active retrotansposons could be found. Based on the previous studies,it is considered that the activation of retrotansposons is associated with DNA damage. So carcinogenic agent MMS, which directly impacted on the DNA molecule, was first selected. Results showed that most of the genes participating in gene damage reparation, especially in homologous recombination (HR) progress, were transcriptionally activated, and most of the seleted retrotransposons ORFs were activated except TCA8 (ORF19.6078 and orf19.6079). Further studies were carried out to investigate the relative expression for retrotansposons protein encoded regions in response to kinds of environmental stresses such as (Hyperosmotic、H_2O_2、azole drug ). The concentration of all these stresses reached half of lethal dose (IC50). It is showed that genes involving in DNA damage reparation were widely upregulated in the response to miconzole (MCZ) and H_2O_2 stress, and TCA3 (ORF19.2219)、TCA11 (ORF19.6469) and Zorro2 (ORF19.7274 and ORF19.7275) were transcriptionally activated under the treatment with MCZ for 6 h; And TCA8 was selectively activated under the treatment with H_2O_2 for 6 h. Moreover, the activated repair genes showed priority to retrotansposons activity in time. However, hyperosmotic stress, neither NaCl hyperosmotic nor sorbital hyperosmotic, couldn’t increase the retrotansposons expression, and no up-regulated genes involving DNA-damage repair were found in response to hyperosmotic. It is suggested that the regulation function for retrotansposons activity is condition-selective, and closely related with cell gene damage repair pathway.
     To further explore the possible mechanism for retrotansposons transcriptionally activity induced by MCZ and H_2O_2 stress, anti-oxidant NAC was added before the two kinds of stresses. The combinated effects on the strains growth, the relayive expression changes of retrotansposons and damage repair related genes, and the cellular ROS level were acquired to evaluate the combination function between NAC and MCZ, H_2O_2 stresses. Results showed that NAC could inhibit the killing cells caused by MCZ and effectively protect the yeast state cells, while no function was found under H_2O_2 stress; The up- regulated retrotansposons induced by MCZ and H_2O_2 stress were decreased and almost all the activity of damage repair genes were significantly reduced with the function of NAC; Besides, the generated intracellular ROS caused by MCZ and H_2O_2 stress could be completely inhibited with the combination function of NAC according to fluorenscence intensity detection. We proposed that accumulation of ROS by MCZ and H_2O_2 stress could indirectly cause cell oxidative damage, start the DNA damage repair parthway, and finally regulate the expression of retrotansposons.
     In the last part, to evaluate the function of activated retrotransposon, southern blotting technique was adopted to in-depth analysis of those active retrotansposons element whether capable of performing all the steps of the replication cycle, up to and including the generation of full-length double-stranded DNA molecules. Several strains were selected under long time pressure in the liquid medium (YPD). The digested genome of parental and derivative strains, were hybridized to particular probe for retrotansposons elements. The results revealed that more copy numbers of Zorro2 were found in the MCZ induced strains, while decrease of TCA3 copy numbers in derivative strains. Besides, TCA8 copy number was also seemed to increase in H_2O_2 induced strains. Using broth microdilution method and spot assay, all the derivative strains represented increased tolerance to the matching stress respectively. It is indicated that stress could change the copy numbers of retrotansposons, and the genomic remodeling due to retrotransopsoms may change the host gene expression through a number of different ways, and be capable to improve the ability to adapt to environment.Therefore, we propsose that the potential regulation function for the genome in C.albicans would become internal power for genetic evolution, and the high adaptive ability of C. albicans may closely related to the regulation function of widespread retrotansposons in C. albicans genome.
引文
1. Wisplinghoff H, Bischoff T, Tallent S.M., et al. Nosocomial bloodstream infections in US hospitals: analysis of 24,179 cases from a prospective nationwide surveillance study [J]. Clin Infect Dis, 2004, 39: 309-317.
    2.吴绍熙等.中国致病真菌10年动态流行病学研究[J].临床皮肤科杂志, 1999, 28(1):1- 44.
    3.廖万青,吴绍熙。真菌研究进展。第二军医大学出版社,1998,6:11
    4. Richard, Calderone, et al. Signalling and oxidant adaptation in Candida albicans and Aspergillus fumigatus [J]. Nature Review. 2006, June, (4): 435-444
    5. Brakebusch M, Wintergerst U, Petropoulou T, Notheis G, et al. Bromelain is an accelerator of phagocytosis, respiratory burst and killing of Candidas albicans by human granulocytes and monocytes [J]. Eur J Med Res. 2001, 6(5): 193-200
    6. Sanglard D, Ischer F, Koymans L, et al. Amino acid substitutions the cytochrome P450 Lanosterol 14a demethylase (CYP51A1) from azole resistance Candida albicans clinical isolates contribute to resistance to azole antigungal agents[J ]. Antimicrob Agents Chemother, 1998, 42 (2): 241-2531
    7. Marichal P, Koymans L,Willemsens S, et a1. Contribution of mutations in the cytochrome P450 14alpha-demethylase (Ergllp, Cyp51p) to azole resistance in Candida albicans [J]. Microbiology, 1999, 145(10): 2701-2713.
    8. Franz R, et a1. Multiple Molecular Mechan isms Contribute to a Stepwise Development of Fluconazole Resistance in clinical Candida albicans Strains. Antimicrob [J]. Agents Chemother, 1998, 42(12):3065-3072.
    9. Wada S, Niimi M, Niimi K, et al. Candida glabrata ATP-binding cassette transporters Cdrlp and Pdh1p expressed in a Saccharomyces cerevisiae strain deficient in membrane transporters show phosporylation-dependent pumping properties [J]. J Biol Chem, 2002, 277: 46809-46821
    10. Marchetti O, Moreillon P, Entenza JM, et al. Fungicidal synergism of fluconazole and cyclosporine in Candida albicans is not dependent on multidrug efflux transporters encoded by the CDR1, CDR2, CaMDR1, and FLU1 genes [J]. Antimicrob Agents Chemother, 2003, 47:1565-1570
    11. de Michefi M, Bille J, Schueller C, et a1. A common drug-responsive element mediates the upregulation of the Candida albicans ABC tansporters CDR1 and CDR2,two genes involved in antifungal drug resistance [J]. Mol Microbiol, 2002, 43(5): 1197-1214.
    12. Donlan RM, Costerton JW. Biofilms: survival mechanisms of clinically relevant microorganism [J]. Clin Microbiol Rev, 2002, 15:167-193
    13. H.C. Van der Mei et al. Effect of probiotic bacteria on prevalence of yeasts in oropharyngealbiofilms on silicone rubber voice prostheses in vitro [J]. Med.Microbiol, 2000, 49: 713-718
    14. A. Brooun, et al. A dose-response study of antibiotic resistance in Pseudomonas aeruginosa biofilms. Antimicrob[J]. Agents Chemother, 2002, 4 4: 640-646.
    15. Richard D. Cannon, et al. Candida albicans drug resistance-another way to cope with stress [J]. Microbiology, 2007, 153:3211–3217
    16. Ikner A, Shiozaki K. Yeast signaling pathways in the oxidative stress response[J]. Mutat Res, 2005, 569 (1-2):13-27.
    17. Moye-Rowley WS. Transcription factors regulating the response to oxidative stress in yeast [J]. Antioxid Redox Signal. 2002, 4(1):123-40
    18. Stemberg R M, NovickG E, Cao G P. Genome canalization: the coevolution of transposable and interspersed repetitive element with single copy DNA [J]. Genetica, 1992, 86:215-246
    19. Boeke, J D, Garfinkel, D J, Styles, C.A. and Fink, G R. Ty elements transpose through an RNA intermediate [J]. Cell, 1985, 40: 491–500.
    20. Kumar A, Bennetzen JL. Plant retrotransposons [J]. Annual Review of Geneics, 1999, 33: 479-532.
    21.张胜利许桂芳李东方李学斌吴大付。逆转座子对真核生物基因组及宿主基因表达的影响[J]。核农学报,2010, 24(2): 314-318
    22. Nicholas J. Holton, Timothy J D Goodwin, Margaret I. Butler, et al. An active retrotransposon in Candida albican [J]. Nucleic Acids Research, 2001, 29: 194014-4024.
    23. Timothy J D Goodwin, Joanne E. Ormandy, Russell T M Poulter. L1-like non-LTR retrotransposons in the yeast Candida albicans [J].Curr Genet, 2001, 39: 83-91.
    24. Labrador M, Comes V.G. Transposable elements-host interactions: Regulation of insorsion and excision [J]. Annu Rev Genet, l997, 31:38l-404.
    25.徐来祥,张知彬,宋铭晶。逆转座子与生物遗传多样性[J]。动物学杂志,2002,37: 88-92.
    26. Cheng C, Daigen M, Hirochika H. Epigenetic regulation of the rice retrotransposon Tosl7 [J]. Molecular Genetics and Genomics, 2006, 276(4):378-390.
    27. Rehwinkel J, Natalin P, Stark A, Brennecke J, Cohen SM, Izaurralde E. Genome-wide analysis of mRNAs regulated by Drosha and Argonaute proteins in Drosophila melanogaster [J]. Mol Cell Biol, 2006, 26(8): 2965–2975.
    28. Slotkin RK, Martienssen R. Transposable elements and the epigenetic regulation of the genome [J]. Nat Rev Genet, 2007, 8(4): 272–285.
    29. Rolfe, M., Banks, G. Induction of yeast Ty element transcription by ultraviolet light [J]. Nature, 1986, 319:339–340.
    30. Paquin, C E, Williamson, V M. Temperature effects on the rate of Ty transposition [J]. Science, 1984,226:53–55.
    31. Santos, R., Schenberg, A.S.G., Gardner, D.S.G., Oliver, S.G. Enhancement of Ty transposition at the ADH4 and ADH2 loci in meiotic yeast cells. Mol. Gen. Genet. 1997, 254:555–561.
    32. Teodora Stoycheva, Domenica Rita Massardo, Margarita Pesheva c, et al. Ty1 transposition induced by carcinogens in Saccharomyces cerevisiae yeast depends on mitochondrial function [J]. Cryobiology, 2008, 56 : 241–247.
    33. Ji, H., Moore, D.P., Blomberg, M.A., Braiterman, L.T., et al. Hotspots for unselected Ty1 transposition events on yeast chromosome III are near tRNA genes and LTR sequences [J]. Cell, 1993, 73:1007–1018.
    34. Zou, S., Ke, N., Kim, J.M. and Voytas, D.F. The Saccharomyces retrotransposon Ty5 integrates preferentially into regions of silent chromatin at the telomeres and mating loci[J]. Genes Dev., 1996, 10: 634–645.
    35.吴绍熙.现代医学真菌检验手册[M].北京;北京医科大学、中国协和医科大学联合社. 1998, 332-356.
    36. Gasch AP, Spellman PT, Kao CM, et al. Genomic expression programs in the response of Yeast cells to environmental changes [J]. Mol Biol Cell, 2000, 11(12): 4241-57.
    37. National Committee for Clinical Laboratory Standards.2002. Reference method for broth dilution antifungal suscepetibility testing of filamentous fungi; Approved standards. Documents M38-A, Wayne, Pa.
    38. SanMiguel, P., Tikhonov, A., Jin, Y.-K., et al. Nested retrotransposons in the intergenic regions of the maize genome [J]. Science, 1996, 274, 765-768.
    39. M. Pesheva, O. Krastanova, L. Staleva, et al. The Ty1 transposition assay: a new short-term test for detection of carcinogens [J]. Microbiol. Methods, 2005, 61:1-8.
    40. L. Staleva, P.V. Venkov. Activation of Ty1 transposition by mutagens [J]. Mutat.Res. 2001, 474:93–103.
    41. V.A. Bradshow, K. McEntee, DNA damage activates transcription and transposition of yeast Ty1 retrotransposons [J]. Mol. Gen. Genet, 1989, 218: 464-474.
    42. Derek T. Scholes, Alison E. Kenny, Eric R. Gamache, et al. Activation of a LTR- retrotransposon by telomere erosion [J]. PNAS, 2003, 100(26): 15736-15941.
    43. Gasch, A. P., Huang, M., Metzner, S, et al. Genomic Expression Responses to DNA-damaging Agents and the Regulatory Role of the Yeast ATR Homolog Mec1p [J]. Mol. Biol. Cell, 2001, 12(10), 2987–3003.
    44. Juan Lucas Argueso, James Westmoreland, Piotr A. Mieczkowski, et al. Double-strand breaksassociated with repetitive DNA can reshape the genome [J]. PANS, 2008, 105(33), 11845-11850.
    45. Yoshida Y., Cytochrome P450 of fungi: primary target for azole antifungal agents [J]. Curr Top Med Mycol, 1988, 2: 388-418.
    46. Kobayashi, D., Kondo, K., Uehara, N., Otokozawa, S., Tsuji, N., et al, Endogenous reactive oxygen species is an important mediator of miconazole antifungal effect. Antimicrob [J]. Agents Chemother, 2002, 46: 3113–3117.
    47. Francois, Isabelle E. J. A., Cammue, Bruno P. A., Borgers, M., Ausma, J., Disoersyn, G. D., et al. Azoles: mode of antifungal action and resistance development: Effect of miconazole on endogenous reactive oxygen species production in Candida albicans [J]. Curr Med Chem, 2006, 5: 1-11.
    48. Thevissen, K., Ayscough, K. R., Aerts, A. M. Miconazole induces changes in actin cytoskeleton prior to reactive oxygen species induction in yeast [J]. J Biol Chem, 2007, 282: 21592–21597.
    49. E.J. Kendall, B.D. McKersie. Free radical and freezing injury to cell membranes of wheat [J]. Plant Physiol, 1989, 76: 86-94.
    50. T.C. Meng, T. Fukada, N. Tonks. Reversible oxidation and inactivation of protein tyrosine phosphatases in vivo [J]. Mol. Cell, 2002, 9: 387-399.
    51. D. Namagaladze, D. Naga, W. Hofer, V. Ullrich. Redox control of calcineurin by targeting the binuclear Fe2+ Zn2+ center at the enzyme active site [J]. J. Biol. Chem, 2002, 277: 5962-5969.
    52. R. Rainwater, D. Parks, M. Anderson, P. Tegtmeyer, K. Mann. Role of cysteine residues in regulation of p53 function [J]. Mol. Cell. Biol, 1995, 15: 3892-3903.
    53. J.D. Boeke, S.B. Sandmayer, J.R. Broach. Yeast transposable elements, in: J.R. Pringle, E.W. Jones (Eds.), The Nuclear and Cellular Biology of the Yeast Saccharomyces cerevisiae. Cold Spring Harbor Laboratory Press, Cold Spring Harbour, N.Y., 1991, 193–261.
    54. C.W. Lawrence, D.C. Hinkle. DNA polymerase zeta and the control of DNA damage induced mutagenesis in eukaryotes [J]. Cancer Surv, 1996, 28: 21-31.
    55. M. Joan Curcio, Alison E. Kenny, Sharon Moore, David J. Garfinkel, Matthew Weintraub, Eric R. Gamache, and Derek T. Scholes. S-Phase Checkpoint Pathways Stimulate the Mobility of the Retrovirus-Like Transposon Ty1 [J]. Molecular and Celluar biology, 2007, 27(24): 8874-8885.
    56. Moore, J. K., and Haber, J. E., Capture of retrotransposon DNA at the sites of chromosomal double-strand breaks [J]. Nature, 1996, 383: 644-646.
    57. Teng, S. C., Kim, B., and Gabriel, A. Retrotransposon reverse-transcriptase -mediated repair of chromosomal breaks [J]. Nature, 1996, 383: 641–644.
    58. Morrish, T. A., Gilbert, N., Myers, J. S., Vincent, B. J., Stamato, T. D., et al, DNA repair mediated by endonuclease-independent LINE-1 retrotransposition [J]. Nat Genet, 2002, 31: 159-165.
    59. Wilke, C. M., and Adams, J. Fitness Effects of Ty Transposition in Saccharomyces cerevisiae [J]. Genetics, 1992, 131:31-42.
    60. Kazazian H H, Moran J V. The impact of L1 retrotransposons on the human genome [J]. Nature Genetics, 1998, 19 (1): 19-24.
    61. Boeke J D. Lines and Alu-the poly A connection [J]. Nature Genetics, 1997, 16 (1): 6-7
    62.Timothy J.D. Goodwin, Damian E. Dalle Nogare, Margaret I. Butler, and Russell T. M. Poulter. Ty3/gypsy-like retrotransposons in Candida albicans and Candida dubliniensis: Tca3 and Tcd3 [J]. Yeast, 2003; 20: 493–508.
    1. Pfaller MA and Diekema DJ. Epidemiology of invasive candidiasis: a persistent public health problem[J]. Clinical Microbiology Reviews , 2007, 20: 133–163.
    2. Wisplinghoff H, Bischoff T, Tallent S.M., et al. Nosocomial bloodstream infections in US hospitals:analysis of 24,179 cases from a prospective nationwide surveillance study[J]. Clinical Infectious Disease, 2004, 39: 309–317.
    3. Chiatogu Onyewu, Jill R. Blankenship, Maurizio Del Poeta, et al. Ergosterol Biosynthesis Inhibitors become fungicidal when combined with calcineurin inhibitors against Candida albicans, Candida glabrata, and Candida krusei[J]. Antimicrobial Agents and Chemotherapy, 2003, 47(3): 956-964.
    4. Xu Yong-hao,Chen La-mei and Li Chuan-yang. Susceptibility of clinical isolates of Candida species to fluconazole and detection of Candida albicans ERG11 mutations[J]. The Journal of Antimicrobial Chemotherapy, 2008, 61(4): 798-804.
    5. Lamb DC, Kelly DE, Schunck WH, et al. The mutation T315A in Candida albicans sterol 14-demethylase causes reduced enzyme activity and fluconazole resistance through reduced affinity [J]. The Journal of biological chemistry, 1997, 272: 5682-5688.
    6. Sanglard D, Ischer F, Koymans L, et al. Amino Acid Substitutions in the Cytochrome P-450 Lanosterol 14α-Demethylase (CYP51A1) from Azole-Resistant Candida albicans Clinical Isolates Contribute to Resistance to Azole Antifungal Agents[J]. Antimicrob Agents Chemother, 1998, 42(2): 241–253.
    7. Lamb DC,Kelly DE,White TC,et a1.The R467K amino acid substitution in Candida albicans sterol 14alpha-demethylase causes drug resistance throush reduced afinity[J].Antimicrob Agents Chemother, 2000, 44(1):63-67
    8. Podust LM,Poulos TL,Waterman MR.Crystal structure of cytochrome P450 14 a-sterol demethylase (CYP51) from Mycobacterium tuberculosis in complex witlI azole inhibitors[J].Proceedings of the National Academy of Sciences, 2001, 98(6):3068-3073.
    9. Makiko Kudo, Miwa Ohi, Yuri Aoyama, et al. Effects of Y132H and F145L Substitutions on the Activity, Azole Resistance and Spectral Properties of Candida albicans Sterol 14-Demethylase P450 (CYP51): A Live Example Showing the Selection of Altered P450 through Interaction with Environmental Compounds[J]. Journal of Biochemistry, 2005, 137(5): 625-632.
    10. Dunkel N, Liu TT, Barker KS, et al. A Gain-of-Function Mutation in the Transcription Factor Upc2p Causes Upregulation of Ergosterol Biosynthesis Genes and Increased Fluconazole Resistance in a Clinical Candida albicans Isolate [J]. Eukaryot Cell, 2008, 7(7): 1180–1190.
    11. Heilmann CJ, Schneider S, Barker KS, et al. An A643T mutation in the transcription factor Upc2p causes constitutive ERG11 upregulation and increased fluconazole resistance in Candida albicans[J]. Antimicrob Agents Chemother, 2010, 54(1):353-359.
    12. Yan L, Zhang J, Li M, et al. DNA microarray analysis of fluconazole resistance in a laboratory Candida albicans strain[J]. Acta Biochimica Sinica, 2008, 40(12):1048-1060.
    13. Miyazaki T, Miyazaki Y, Izumikawa K, et al. Fluconazole treatment is effective against a Candida albicans erg3/erg3 mutant in vivo despite in vitro resistance[J]. Antimicrob Agents Chemother, 2006, 50(2): 580-586.
    14. Pierson CA, Jia N, Mo C, et al. Strurm A.M., Eckstein J, et al. Isolation, characterization, and regulation of the Candida albicans ERG27 gene encoding the sterol 3-keto reductase[J]. Medical mycology, 2004, 42(5): 461-473.
    15. Mukhopadhyay K, Prasad T, Saini P, et al. Membrane sphingolipid-ergosterol interactions are important determinants of multidrug resistance in Candida albicans[J]. Antimicrob Agents Chemother, 2004 , 48(5): 1778-1787.
    16. Sun Wei-wei, Gao Ping-hui, Jiang YuanYing, et al. ATP-binding-cassette transporters and fluconazole-resistance of clinical Candida albicans strains [J]. Acadenic Journal of Second Military Medical University(第二军医大学学报), 2008, 29(9):1038-1041.
    17. Haque A, Rai V, Bahal BS, et al. Allelic variants of ABC drug transporter Cdr1p in clinical isolates of Candida albicans[J]. Biochemical and biophysical research communications, 2007, 352(2): 491-497.
    18. Holmes AR, Tsao S, Ong SW, et al. Heterozygosity and functional allelic variation in the Candida albicans efflux pump genes CDR1 and CDR2[J]. Molecular Microbiology, 2006, 62(1): 170-186.
    19. Shukla S, Saini P, Smiriti, et al. Functional characterization of Candida albicans ABCtransporter Cdr1p[J]. Eukaryotic cell. 2003, 2(6): 1362-1375.
    20. Shukla S, Ambudkar SV and Prasad R. Substitution of threonine-1351 in the multidrug transporter Cdr1p of Candida albicans results in hypersusceptibility to antifungal agents and is essential for synergic effects of calcineurin inhibitor FK520[J]. Journal of Antimicrobial Chemotherapy, 2004, 54(1): 38-45.
    21. Gao PH, Cao YB, Jia XM, et al. Drug susceptibilities of yeast cells are affected when expressing mutant Candida albicans drug resistance protein[J]. International Journal of antimicrobial Agents, 2006, 28(1): 69-74.
    22. Jha S, Karnani N, Dhar SK, et al. Purification and characterization of N-terminal nucleotide-binding domain of an ABC drug transporter of Candida albicans: uncommon cysteine 193 of Walker A is critical for ATP hydrolysis[J]. Biochemistry, 2003, 42(36): 10822-10832.
    23. Loo TW, Bartlett MC, and Clarke DM. The“LSGGQ”motif in each nucleotide-domain of human P-glycoportein is adjacent to the opposing Walker A sequence[J]. The Journal of Biological Chemistry, 2002, 277: 41303-41306.
    24. Coste A, Selmecki A, Forche A, et al. Genotypic evolution of azole resistance mechanisms in sequential Candida albicans isolates[J]. Eukaryot Cell, 2007, 6(10): 1889-1904.
    25. Coste A, Turner V, Ischer F, et al. A mutation in Tac1p, a transcription factor regulating CDR1 and CDR2, is coupled with loss of heterozygosity at chromosome 5 to mediate antifungal resistance in Candida albicans[J]. Genetics, 2006, 172(4): 2139-2156.
    26. Morschh?user J, Barker KS, Liu TT,et al. The transcription factor Mrr1p controls expression of the MDR1 efflux pump and mediates multidrug resistance in Candida albicans[J]. PLoS Pathog,2007, 3(11) :e164.
    27. Gaur N.A., Manoharlal R, Saini P, et al. Expression of the CDR1 efflux pump in clinical Candida albicans isolates is controlled by a negative regulatory element[J]. Biochemical and biophysical research communications, 2005, 332(1): 206-214.
    28. Selmecki A, Forche A and Berman J. Aneuploidy and isochromosome formation in drug-resistant Candida albicans[J]. Science, 2006 ,313(5785): 367-370.
    29. Selmecki A, Gerami-Nejad M, Paulson C, et al. An isochromosome confers drug resistance in vivo by amplification of two genes, ERG11 and TAC1[J]. Molecular Microbiology, 2008, 68(3): 624–641.
    30. Denning DW.Echinocandins:a new class of antifungal [J].Journal of AntimicrobialChemotherapy, 2002, 49: 889—891.
    31. Monk BC, Niimi K, Lin S, et a1. Surface-active fungicidal D-peptide inhibitors of the plasma membrane proton pump that block azole resistance[J]. Antimicrob Agents Chemother, 2005, 49:57-70.
    32. Karl E. Miletti and Michael J. Leibowitz. Pentamidine Inhibition of Group I Intron Splicing in Candida albicans Correlates with Growth Inhibition[J]. Antimicrobial Agents and Chemotherapy, 2000, 44(4):958-966

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