Alternative splicing of tau exon 10 produces tau isoforms with either 3 (3R) or 4 (4R) repeated microtubule-binding domains. Increased ratios of 4R to 3R tau expression, above the physiological 1:1, leads to neurofibrillary tangles and causes neurodegenerative disease. An RNA stem loop structure plays a significant role in determining the ratio, with decreasing stability correlating with an increase in 4R tau mRNA expression. Recent studies have shown that aminoglycosides are able to bind and stabilize the tau stem loop in vitro, suggesting that other druglike small molecules could be identified and that such molecules might lead to decreased exon 10 splicing in vivo. The authors have developed a fluorescent high-throughput fluorescent binding assay and screened a library of ∼110,000 compounds to identify candidate drugs that will bind the tau stem loop in vitro. In addition, they have developed a fluorescent-based RNA probe to assay the stabilizing effects of candiate drugs on the tau stem loop RNA. These assays should be applicable to the general problem of identifying small molecules that interact with mRNA secondary structures. (Journal of Biomolecular Screening 2007:789-799)
Lee VM, Goedert M., Trojanowski JQ: Neurodegenerative tauopathies. Annu Rev Neurosci2001;24:1121-1159.
2.
Neve R., Harris P., Kosik K., Kurnit D., Donlon T.: Identification of cDNA clones for the human microtubule-associated protein, tau, and chromosomal localization of the genes for tau and microtubule-associated protein 2. Mol Brain Res1986;1:271-280.
3.
Kosik KS, Orecchio LD, Bakalis S., Neve RL: Developmentally regulated expression of specific tau sequences. Neuron1989;2(4):1389-1397.
4.
Andreadis A. , Brown WM, Kosik KS: Structure and novel exons of the human tau gene. Biochemistry1992;31(43):10626-10633.
5.
Gustke N., Trinczek B., Biernat J., Mandelkow EM, Mandelkow E.: Domains of tau protein and interactions with microtubules. Biochemistry1994;33(32):9511-9522.
6.
Hutton M., Lendon CL, Rizzu P., Baker M., Froelich S., Houlden H., et al: Association of missense and 5′-splice-site mutations in tau with the inherited dementia FTDP-17. Nature1998;393)6686):702-705.
7.
D'Souza I., Schellenberg GD: Regulation of tau isoform expression and dementia. Biochim Biophys Acta2005;1739(2-3):104-115.
8.
Jiang Z., Cote J., Kwon JM, Goate AM, Wu JY: Aberrant splicing of tau pre-mRNA caused by intronic mutations associated with the inherited dementia frontotemporal dementia with parkinsonism linked to chromosome 17. Mol Cell Biol2000;20(11):4036-4048.
9.
Varani L., Hasegawa M., Spillantini MG, et al: Structure of tau exon 10 splicing regulatory element RNA and destabilization by mutations of frontotemporal dementia and parkinsonism linked to chromosome 17. Proc Natl Acad Sci U S A1999;96(14):8229-8234.
10.
Donahue CP, Muratore C., Wu JY, Kosik KS, Wolfe MS: Stabilization of the tau exon 10 stem loop alters pre-mRNA splicing . J Biol Chem2006; 281(33):23302-23306.
11.
Varani L., Spillantini MG, Goedert M., Varani G.: Structural basis for recognition of the RNA major groove in the tau exon 10 splicing regulatory element by aminoglycoside antibiotics. Nucleic Acids Res2000; 28(3):710-719.
12.
Hannon GJ, Rossi JJ: Unlocking the potential of the human genome with RNA interference . Nature2004;431(7006):371-378.
13.
Tor Y.: Targeting RNA with small molecules. Chembiochem2003;4(10): 998-1007.
14.
Zaman GJ, Michiels PJ, van Boeckel CA: Targeting RNA: new opportunities to address drugless targets. Drug Discov Today2003;8(7):297-306.
15.
Thomas JR, Liu X., Hergenrother PJ: Biochemical and thermodynamic characterization of compounds that bind to RNA hairpin loops: toward an understanding of selectivity. Biochemistry2006;45(36):10928-10938.
16.
Michael K., Wang H., Tor Y.: Enhanced RNA binding of dimerized aminoglycosides. Bioorg Med Chem1999;7(7):1361-1371.
17.
Kirk SR, Luedtke NW, Tor Y.: Neomycin-acridine conjugate: a potent inhibitor of Rev-RRE binding. Bioorg Med Chem2000;122:980-981.
18.
Hamasaki K. , Rando RR: A high-throughput fluorescence screen to monitor the specific binding of antagonists to RNA targets. Anal Biochem1998;261(2):183-190.
19.
Xue CB, Voss ME, Nelson DJ, et al: Design, synthesis, and structure-activity relationships of macrocyclic hydroxamic acids that inhibit tumor necrosis factor alpha release in vitro and in vivo. J Med Chem2001; 44(16):2636-2360.
20.
Zhang JH, Chung TD, Oldenburg KR: A simple statistical parameter for use in evaluation and validation of high-throughput screening assays. J Biomol Screen1999;4(2):67-73.
21.
Lee J., Kwon M., Lee KH, et al: An approach to enhance specificity against RNA targets using heteroconjugates of aminoglycosides and chloramphenicol (or linezolid). J Am Chem Soc2004;126(7):1956-1957.
22.
Xue L., Charles I., Arya DP: Pyrene-neomycin conjugate: dual recognition of a DNA triple helix . Chem Commun (Camb)2002;1:70-71.
23.
Arya DP, Micovic L., Charles I., Coffee RL Jr, Willis B., Xue L.: Neomycin binding to Watson-Hoogsteen (W-H) DNA triplex groove: a model. J Am Chem Soc2003;125(13):3733-3744.
24.
Arya DP, Xue L., Willis B.: Aminoglycoside (neomycin) preference is for A-form nucleic acids, not just RNA: results from a competition dialysis study. J Am Chem Soc2003;125(34):10148-10149.
25.
Hermann T.: Chemical and functional diversity of small molecule ligands for RNA . Biopolymers2003;70(1):4-18.
26.
Buratti E., Baralle FE: Influence of RNA secondary structure on the pre-mRNA splicing process . Mol Cell Biol2004;24(24):10505-10514.
27.
Tucker BJ, Breaker RR: Riboswitches as versatile gene control elements. Curr Opin Struct Biol2005;15(3):342-348.
28.
Mandal M., Breaker RR: Gene regulation by riboswitches. Nat Rev Mol Cell Biol2004;5(6):451-463.
29.
Lipscombe D. : Neuronal proteins custom designed by alternative splicing. Curr Opin Neurobiol2005;15(3):358-363.
30.
Blencowe BJ: Splicing on the brain. Nat Genet2005 ;37(8):796-797.
31.
Krawczak M. , Reiss J., Cooper DN: The mutational spectrum of single base-pair substitutions in mRNA splice junctions of human genes: causes and consequences . Hum Genet1992;90(1-2):41-54.
32.
Stamm S., Ben-Ari S., Rafalska I., et al: Function of alternative splicing. Gene2005;344:1-20.
