The invention relates to the identification and use of the DAF-2/IR responsive sod-3 promoter. Transgenic
1. An isolated nucleic acid molecule comprising the nucleic acid sequence of SEQ ID NO:1. 2. The isolated nucleic acid molecule of 3. An isolated nucleic acid molecule comprising a nucleic acid sequence that hybridizes to the nucleic acid sequence of SEQ ID NO:1. 4. The nucleic acid molecule of 5. The isolated nucleic acid molecule of 6. An isolated nucleic acid molecule comprising a promoter exhibiting the biological activity of the sod-3 promoter, wherein the nucleic acid sequence is selected from the group consisting of:
(a) a nucleic acid sequence that has 90% or greater sequence identity to the nucleic acid sequence of SEQ ID NO:1. (b) a fragment of the nucleic acid sequence of (a) or of the sequence of SEQ ID NO:1; and (c) a derivative of the nucleic acid sequence of (a) or (b). 7. The nucleic acid molecule of 8. The nucleic acid molecule of 9. The nucleic acid molecule of 10. An isolated nucleic acid molecule comprising the nucleic acid molecule of 11. An isolated nucleic acid molecule comprising the nucleic acid molecule of 12. A vector comprising the nucleic acid molecule of 13. The vector of 14. The vector of 15. A vector comprising the nucleic acid molecule of 16. The vector of 17. The vector of 18. A transgenic host cell transformed with the nucleic acid molecule of 19. The transgenic host cell of 20. A transgenic host comprising the host cell of 21. The transgenic host of 22. A transgenic host cell transformed with the nucleic acid molecule of 23. The transgenic host cell of 24. A transgenic host comprising the host cell of 25. The transgenic host of 26. A method for identifying a modulating compound, the method comprising
(a) providing transgenic (b) contacting the transgenic (c) measuring reporter gene activity in the absence and in the presence of the at least one compound; (d) comparing the reporter gene activities of step (c); and (e) selecting thereby at least one compound. 27. The method of 28. The method of 29. A method for identifying a modulating compound, the method comprising
(a) providing transgenic (b) contacting the transgenic (c) measuring reporter gene activity in the absence and in the presence of the at least one compound; (d) comparing the reporter gene activities of step (c); and (e) selecting thereby at least one modulating compound. 30. The method of 31. The method of 32. A process for identifying modulators of the DAF-21lR pathway, the method comprising:
(a) providing transgenic (b) contacting the transgenic (c) measuring the amount of L1 larvae in the absence and in the presence of, the at least one compound; (d) comparing the amount of L1 larvae which entered into dauer larvae state with the amount of L1 larvae which did not enter into dauer larvae state; and (e) selecting thereby at least one modulating compound. 33. The method of 34. A process for identifying modulators of the DAF-2/IR pathway, the method comprising:
(a) providing transgenic (b) contacting the transgenic (c) measuring the amount of L1 larvae in the absence and in the presence of the at least one compound; (d) comparing the amount of L1 larvae which entered into dauer larvae state with the amount of L1 larvae which did not enter into dauer larvae state; and (e) selecting thereby at least one modulating compound. 35. The method of
[0001] The present invention relates to a process for the screening and identification of compounds modulating directly or indirectly the FOXO forkhead transcription factor activity (“FOXO activity”), transgenic [0002] In abundant food, [0003] In the past, temperature-sensitive strains have been identified that are dauer-constitutive; e.g., at the restrictive temperature of 25° C. these strains form dauers even in the presence of food (Gems, 1998). It turns out that many of these strains, termed daf strains, have acquired mutations in genes involved in the nematode insulin/IGF-1 signaling pathway. Studies of the phenotypes have allowed certain daf genes to be ordered into a genetic pathway consisting of DAF-2/IR, age-1/PI-3 Kinase, pdk-1, akt-1, akt-2, and the FOXO transcription factor DAF-16 (Gottlieb and Ruvkun, 1994; Riddle, 1977; Riddle et al, 1981, Kaestner et al., 2000). [0004] It has been shown by Northern blotting and RT-PCR that the expression of the sod-3 gene is regulated by mutations in the DAF-2/insulin receptor pathway (Honda & Honda, 1999). Inactivation of the DAF-2 function in certain mutant strains results in a strong up-regulation of the sod-3 expression. Honda & Honda suggested that DAF-16 is the transcription factor activating the sod-3 gene and that DAF-16 is inhibited by the DAF-2/IR pathway. [0005] Furthermore, a consensus sequence binding to the transcription factor DAF-16 has been identified and this sequence was shown to be present in the sod-3 upstream regulatory region (Furuyama et al., 2000). This binding motif fused to a minimal promoter was sufficient for insulin-regulated expression in mammalian tissue culture systems. [0006] Since the DAF-2/insulin receptor pathway and its components are very well conserved in man, it was proposed to use the dauer phenotype to identify modulators of the insulin/IGF-1 signaling in man (WO 98/51351 A1). However, the assay systems according to the prior art require long incubation times until the developmental program of the dauer larvae has been completed (usually 3-5 days). Such a long time period may result in the degradation of the assay components. Moreover, the impermeable cuticula structure of dauers together with the reduced food-intake might be a setback for compound uptake into the worm. [0007] Therefore, it was the underlying problem of instant invention to provide a process for the identification of compounds that modulate the DAF-2/IR pathway, which does not depend on [0008] It was found by the instant invention that the use of a nucleic acid molecule having the biological activity of an sod-3 gene promoter element surprisingly is of great advantage for the identification of genes or compounds that modulate the activity of the DAF-2/IR pathway, e.g., the sod-3 promoter as deposited at the Deutsche Sammlung für Zellkulturen und Mikroorganismen, Mascheroder Weg 1b, D-38124 Braunschweig, Germany, DSMZ No. 14912 (the 1098 bp fragment after endonuclease digestion with HindIII and BamHI) on Apr. 4, 2002, especially the sod-3 promoter according to Seq. ID No. 1. This regulatory DNA fragment contains the binding site for the FOXO DAF-16 that is functionally linked to the DAF-2/IR pathway via akt-1. In spite of current knowledge of the daf2/IR signalling pathway, a suitable responsive promoter element to monitor signalling activity for [0009] Accordingly, one embodiment of the present invention is an isolated nucleic acid molecule comprising a promoter exhibiting the biological activity of the sod-3 promoter. Preferably, the nucleic acid sequence of the invention is selected from the group consisting of: (a) a nucleic acid sequence comprising the nucleic acid sequence of SEQ ID NO. 1; (b) a nucleic acid sequence that has 80%, 90%, 95% or greater sequence identity to the nucleic acid sequence of (a) having sod-3 promoter activity; (c) a fragment of the nucleic acid sequence of (a) or (b) having sod-3 promoter activity; and (d) a derivative of the nucleic acid sequence of (a), (b) or (c) having sod-3 promoter activity, preferably a DNA or RNA molecule, more preferably having a 80%, 90%, 95%, or greater sequence identity to SEQ ID No. 1; and (e) a nucleic acid sequence that hybridizes, preferably under stringent conditions, to SEQ ID NO:1. A still more preferred embodiment of the nucleic acid molecule according to the invention comprises a promoter exhibiting the biological activity of the sod-3 promoter in nematodes, preferably in [0010] According to instant invention, a promoter exhibiting the biological activity of the sod-3 promoter means any promoter, which is responsive to forkhead transcription factors, preferably, the FOXO forkhead transcription factors (hereinafter “FOXO's”), particularly, DAF-16. Such promoters are, e.g., FOXO1a, FOXO3a or FOXO4 responsive promoters” (Kaestner et al, 2000). [0011] According to the instant invention the term “fragment” means any parts of the nucleic acid molecules of the invention, which are long enough in order to exhibit the biological activity of the sod-3 promoter. [0012] According to the instant invention the term “derivative” means that the sequence may differ from the sequences of the nucleic acid molecules of the invention at one or more positions, exhibiting a high degree of homology to these sequences. Hereby, “homology” means a sequence identity of at least 50%, in particular an identity of at least 60%, preferably of more than 80% and still more preferably a sequence identity of more than 90%. The deviations with respect to the above-described nucleic acid molecule might have been caused by deletion, substitution, insertion or recombination. Moreover, homology means a functional and/or structural equivalence. [0013] The invention further encompasses nucleic acid sequences that hybridize to nucleic acid sequence of SEQ ID NO:1. A nucleic acid molecule is “hybridizable” to another nucleic acid molecule, such as a cDNA, genomic DNA, or RNA, when a single stranded form of the nucleic acid molecule can anneal to another nucleic acid molecule under the appropriate conditions of temperature and solution ionic strength. The conditions of temperature and ionic strength determine the “stringency” of the hybridization. Low stringency hybridization conditions correspond to a Tm of 55° C. (e.g., 5×sodium chloride/sodium citrate (SSC), 0.1% SDS, 0.25% milk, and no formamide; or 30% formamide, 5×SSC, 0.5% SDS). Moderate stringency hybridization conditions correspond to a higher Tm, (e.g., 40% formamide, with 5× or 6×SSC). High stringency hybridization conditions correspond to the highest Tm, (e.g., 50% formamide, 5× or 6×SSC). Hybridization requires that the two nucleic acids contain complementary sequences, although depending on the stringency of the hybridization, mismatches between bases are possible. The appropriate stringency for hybridizing nucleic acids depends on the length of the nucleic acids and the degree of complementation, variables well known in the art. The greater the degree of similarity or homology between two nucleotide sequences, the greater the value of Tm for hybrids of nucleic acids having those sequences. The relative stability (corresponding to higher Tm) of nucleic acid hybridizations decreases in the following order: RNA:RNA, DNA:RNA, DNA:DNA. For hybrids of greater than 100 nucleotides in length, equations for calculating Tm have been derived. For hybridization with shorter nucleic acids, i.e., oligonucleotides, the position of mismatches becomes more important, and the length of the oligonucleotide determines its specificity. [0014] In a particular embodiment of the present invention, a hybridizable nucleic acid molecule of the invention hybridizes under stringent conditions to the nucleic acid molecule comprising the nucleotide sequence of SEQ ID NO:1, a complement thereof, or a fragment thereof. The term “hybridizes under stringent conditions” is describes conditions for hybridization and washing under which nucleotide sequences at least 55%, 60%, 65%, 70% and preferably 75% or more complementary to each other typically remain hybridized. Such stringent conditions are known to those skilled in the art and can be found in “Current Protocols in Molecular Biology”, John Wiley & Sons, N.Y. (1989), 6.3.1-6.3.6. A preferred example of stringent hybridization conditions are hybridization in 6×SSC at about 45° C., followed by one or more washes in 0.2×SSC, 0.1 % SDS at 50-65° C. [0015] Another embodiments of instant invention are isolated nucleic acid molecules comprising the said nucleic acid sequence according to the invention exhibiting sod-3 promoter activity and a nucleic acid sequence conferring the activity of a reporter gene (“fusion molecule”); vectors comprising the nucleic acid molecules according to the invention, which may further be optionally linked to regulatory elements which ensure the transcription and the synthesis of a translatable RNA of a reporter gene in eukaryotic cells or transgenic host cells transformed with the nucleic acid molecule or the vector of instant invention. [0016] Still another embodiment of the invention is the transgenic host or host cell transfected with the nucleic acid molecule or the vector of the invention, which is preferably of nematode origin and the method for their preparation comprising the steps of generating a transgenic host cell, preferably of nematode origin, by use of the nucleic acid molecule or the vector of the invention. [0017] Yet another embodiment of the present invention is a process for the identification of modulators of the DAF-2/IR pathway, AKT pathway and/or of kinases phosphorylating one or more FOXO's (i.e. the “Screening Assay” according to the invention) comprising the said transgenic cell or transgenic organism, preferably a nematode (e.g., [0018] A preferred embodiment of the invention is a process for the identification of modulators of the DAF-2/IR pathway, AKT pathway, of kinases phosphorylating, phosphatases dephosphorylating, and/or other activities (e.g., enzymes) altering the molecular composition, stability (i.e., half-life), subcellular location, or activity of one or more FOXO's comprising [0019] (a) bringing transgenic [0020] (b) measuring the reporter gene activity in the presence of one or more compounds to be tested; [0021] (c) measuring the reporter gene activity in the absence of the one or more compounds to be tested, optionally in the presence of one or more suitable reference compounds; [0022] (d) comparing the reporter gene activities of steps (b) and (c); and [0023] (e) selecting the modulating compound(s) of the DAF-2/IR pathway, AKT pathway, of kinases phosphorylating, phosphatases dephosphorylating, and/or other activities (e.g., enzymes) altering the molecular composition, stability (i.e., half-life), subcellular location, or activity of one or more FOXO's. [0024] Another embodiment of instant invention is a process for the identification of modulators of the DAF-2/IR pathway comprising [0025] (a) bringing a transgenic [0026] (b) measuring the amount of L1 larvae, which enters into dauer larvae state under the condition of step (a) in the absence and in the presence of one or more compounds to be tested, optionally in the presence of one or more suitable reference compounds; [0027] (c) comparing the amounts of L1 larvae, which entered into dauer larvae state according to step (b); and [0028] (d) selecting the modulating compound(s) of the DAF-2/IR pathway. [0029] According to the instant invention the term “modulator” means any chemical molecule or genetic element, which has an inhibitory, activatory or regulatory effect on the DAF-2/IR pathway, AKT pathway, of kinases phosphorylating, phosphatases dephosphorylating, and/or other activities (e.g., enzymes) altering the molecular composition, stability (i.e., half-life), subcellular location, or activity of one or more FOXO's. [0030] According to the instant invention the term “suitable reference compound” means a vanadate salt, e.g., sodium orthovanadate, monoperoxo(picolinato)oxovanadate(V), or potassium bisperoxo(1,10-phenanthroline)oxovanadate (V). [0031] According to the instant invention the term “suitable condition” means any cultivation condition suitable for [0032] According to the instant invention the term “stressful condition” means any cultivation condition suitable for [0033] The Screening Assay of the invention exhibits great advantages in comparison to conventional assays (e.g., assays using exit from dauer larvae state) with respect to speed of the performance of the assay, feasibility of quantification, and avoidance of side effects, e.g., developmental side effects. [0034] Quantifiable reporter genes suitable to practise the assay systems according to instant invention may encode for proteins that can be detected due to their enzymatic or fluorescent properties such as luciferase, β-galactosidase, β-lactamase, secreted alkaline phosphatase, green fluorescent protein, coral reef fluorescent proteins, or other reporters known to the skilled artisan (e.g., Hill et al, 2001). Reporter activity might be measured in lysates of the organisms or in-situ in the living cell or animal. [0035] Activation of the reporter reveals in the identification of inhibitors of the DAF-2/IR or AKT pathway, while a down-regulation of the reporter activity is indicative for activators of the said pathway. The reporter might be used in wild-type [0036] The identified compounds, which inhibit the signaling of the DAF-2/IR pathway components are promising candidates as therapeutic agents in the field of oncology and cardiac hypertrophy, while activators of the said pathway are promising candidates as therapeutic agents in the treatment of diabetes, brain/heart ischemia, or neurodegenerative diseases. [0037] The following examples are not to be understood as limiting the invention but shall merely illustrate the inventive concept: [0038] Material and Methods [0039] Genomic DNA was prepared from wild type [0040] The [0041] To isolate the regulatory sequences of the sod-3 gene, 1266 bp upstream of the start codon were amplified from wild type [0042] Subsequently, the identity of the resulting 1266 bp PCR product was confirmed by sequencing. The GFP expression vector was assembled by cloning into the pPD49.26 backbone a) the 1098 bp BamHI and HindIII fragment of the sod-3 promoter and b) and a PCR fragment of GFP amplified from pPD95.75 containing flanking restriction sites for NheI and KpnI. [0043] The resulting in a [0044] daf-2(e1368) animals and transgenic animals were obtained according to a standard procedure (Mello and Fire, 1995). In contrast to the method of Mello and Fire, the plasmid pMGC2-24 was injected together with the injection marker ttx-3::GFP into the gonads of the said animals. Three independent lines were isolated by isolation of GFP-positive animals. [0045] The regulation of the sod-3 promoter was demonstrated by comparing the expression of sod-3::GFP in daf-2(e1368) animals at different temperatures. The daf-2(e1368) strain contains a temperature-sensitive mutation in the ligand-binding domain of DAF-2/IR resulting in an inactivation of DAF-2 at 25° C. When L1 larvae were grown up at the permissive temperature of 15° C. for 4 days, a weak expression of GFP could be detected in the tail, head, and in the vulva of the adults animals. The overall expression of GFP was quite low. This changed dramatically when L1 larvae were grown up at the restrictive temperature of 25° C. with a concomitant inactivation of DAF-2. Under these conditions, the [0046] Therefore, the regulation of the sod-3::GFP expression correlated with the inactivation of the DAF-2/IR pathway in the daf-2(e1368) strain at 25° C. The data are in agreement with a model in which the DAF-2/IR pathway acts to inhibit the transcription factor DAF-16 which otherwise activates the transcription of the sod-3 gene. Therefore, the reporter is activated when the DAF-2/IR pathway is switched off and deactivated when the DAF-2/IR pathway is switched on. [0047] daf-2(e1368) animals containing the sod-3::GFP reporter were kept at 15° C. until they finished the development to adults and were then shifted as adults to 25° C. (restrictive temperature) to inactivate DAF-2/IR. As seen with dauers, also adults exposed to the restrictive temperature expressed much more GFP in comparison to animals kept at the permissive temperature of 15° C. Densitometric scanning revealed an increase from 2.6±1.7 mean GFP at the permissive temperature to 53.5±14.6 mean GFP at the restrictive temperature. The increase in GFP expression in the adults is in the same order of magnitude as seen with L1 shifted immediately to 25° C. to give dauers (mean GFP: 87.8±35.3). This suggests that the regulation of the sod-3 promoter is independent of the developmental stage of the [0048] SEQ ID No:1 (sod-3 promoter (HindIII×BamHI fragment of DSMZ plasmid pMGC 2-24). The sequence begins and ends with the restriction sites of HindIII, resp., BamHI:
[0049] T. Furuyama, T. Nakazawa, I. Nakano, and N. Mori. Identification of the differential distribution patterns of mRNAs and consensus binding sequences for mouse DAF-16 homologues. Biochem.J. 349 (Pt 2):629-634, 2000. [0050] D. Gems, A. J. Sutton, M. L. Sundermeyer, P. S. Albert, K. V. King, M. L. Edgley, P. L. Larsen, and D. L. Riddle. Two pleiotropic classes of DAF-2 mutation affect larval arrest, adult behavior, reproduction and longevity in [0051] S. Gottlieb and G. Ruvkun. DAF-2, DAF-16 and DAF-23: genetically interacting genes controlling Dauer formation in [0052] S. J. Hill, J. G. Baker, and S. Rees. Reporter-gene systems for the study of G-protein-coupled receptors. [0053] Y. Honda and S. Honda. The DAF-2 gene network for longevity regulates oxidative stress resistance and Mn-superoxide dismutase gene expression in Caenorhabditis elegans. FASEB J. 13 (11):1385-1393, 1999. [0054] K. H. Kaestner, W. Knochel, and D. E. Martinez. Unified nomenclature for the winged helix/forkhead transcription factors. Genes Dev. 14 (2):142-146, 2000. [0055] C. Mello and A. Fire in “ [0056] D. L. Riddle. A genetic pathway for dauer larva formation in [0057] D. L. Riddle, M. M. Swanson, and P. S. Albert. Interacting genes in nematode dauer larva formation. [0058] D. L. Riddle, in “The Nematode [0059] D. L. Riddle and Albert, in “ [0060] J. Sulston and J. Hodgkin in “The Nematode [0061] The foregoing references, as well as all other references cited herein, are incorporated herein by reference in their entirety. FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION
DETAILED DESCRIPTION OF THE INVENTION
EXAMPLES
Example 1
Isolation of the Sod-3 Promoter
forward sod-5U: 5′-agttttaaagattttattcatagtcc-3′; (Seq ID No. 2) reverse sod-3D: 5′-ggatcctttattcactgaaaattagaagatt- (Seq ID No. 3) 3′. Example 2
Transgenic
Example 3
Specific Read-Out for the DAF-2/Insulin Receptor Pathway
Example 4
The Sod-3::GFP Reporter is Regulated Independent of the Developmental Stage
aagcttaaaaatagcagaatttgcaaaacgagcaggaaagtcatattcgcagaaaaaagtcgttgcaaacattcgttt ttatatgtttttctttgagaaagcgtggttcatttttgaaagtgaaaaatatttgcttaaaacttccaaatttaaatctgcagtga ttcagagaggttgagaattattttcaaaaacattcaatgttttcccttggagtgactatgcaaatatgaaaatgttttccaaa aatatttggatgccctgataaaaagtaggtgaaatttcgcaggggaacatcatattaaaatgttgaatttttagaagaaat ggaaatgtttgtcggtggtatgctcgaatatttgagatattatatatttactgttaaatccgaaatttttgacaaacggaaaa aatttgtgtcgaaatactacattttcgataacacaaaggtacttccataacacttataaaaactgtttgactatcttatttcag gaaaaaaaaatccaagaataaacatttttcagaatttgaactttctaatggctgattaataaaacaaagttatacaacta ttcaaagcagttgctcaatctggcattttcttgtgtttttttttgaatatttcatcagcaagatgttgataattttgtgttaattctaat tgttttctacaatttttcaaaccgaaaattgacctttgactttgtttactttgttctcgtgggttaactgttcactgatttctattgctg ttgatgaggtctttgatcaaatttgtattgtttttatactgcatattgcttcaattctaaatcatctaatatattgtcaaacaacttct tgtttttttttcattcaaaacttctgcaaaaacgttctcttaacaaaggttcacacaacaactctcctctccatctctttctctca acaacaatgtgctggccttgcatgtttgccagtgcgggttgtttacgcgttttcaagatttttggtctcctatctaacgtcccg aaatgcattttttcctttcatttggtttttttctgttcgagaaaagtgaccgtttgtcaaatcttctaattttcagtgaataaaggat cc References