Article Figures & Data
Figures
- Fig. 1.
Identification of cdk5 as one of the downstream target genes for ΔFosB in the hippocampus of inducible bitransgenic mice using cDNA expression arrays. A, Schematic diagram of the tetracycline expression system used for the inducible tissue-specific expression of ΔFosB (Chen et al., 1998). Gene 1 encodes the tetracycline transactivator (tTA) under the control of the neuron-specific enolase (NSE) promoter. Gene 2 encodes ΔFosB under the control of the tetracycline-responsive promoter with seven tetracycline operators (TetOp). B, Strategy for searching downstream target genes for ΔFosB in the hippocampus of inducible ΔFosB-expressing bitransgenic mice. Total RNA was isolated from five bitransgenic mice, either expressing or not expressing ΔFosB, and pooled. Poly(A+) RNA was isolated from the pooled total RNA and used as a template for the synthesis of a32P-labeled cDNA probe. The cDNA probes were hybridized to the arrays, and the arrays were analyzed by the PhosphorImager.C, Gene expression profiles of the hippocampus of the bitransgenic mice, either expressing or not expressing ΔFosB, from a portion of the resulting cDNA expression arrays. Positions of the ΔFosB and cdk5 genes are indicated by arrows. The results are representative of three independent determinations.
- Fig. 2.
Upregulation of cdk5 immunoreactivity in the hippocampus of inducible bitransgenic mice after ΔFosB expression.A, A representative immunoblot shows cdk5 levels in the hippocampus of bitransgenic mice expressing (+) or not expressing (−) ΔFosB. B, Levels of cdk5 immunoreactivity are given as arbitrary OD units and are expressed as the mean ± SEM (n = 5 animals in each treatment group). *p < 0.05 by Student's ttest.
- Fig. 3.
Induction of cdk5 promoter activity by ΔFosB.A, Schematic structure of a fragment of the 5′-promoter of the cdk5 gene is shown. Several putative response elements within the promoter region are indicated. The AP-1 site framedby a rectangular box and its adjacent sequences are shown. The AP-1 sequence in a mutated promoter (underlined sequence) is also shown. B, Luciferase activity was measured in a C6 glioma cell line that supports the inducible expression of ΔFosB (Chen et al., 1997) transfected with the wild-type (cdk5-luc) or mutated (mutcdk5-luc) cdk5 promoter in pGL3-basic. Data are expressed as the mean percent change in promoter activity in the presence of ΔFosB compared with that in the absence of ΔFosB (± SEM; n = 3). The results are representative of two independent replications. *p< 0.05 by Student's t test.
- Fig. 4.
Upregulation of cdk5 AP-1-binding activity in the hippocampus of inducible bitransgenic mice after ΔFosB expression.A, The sequence of the cdk5 AP-1 oligonucleotide used as the probe is shown. The 32P-labeled nucleotides are indicated by dots. B, A representative autoradiogram shows the dramatic induction of cdk5 AP-1-binding activity after ΔFosB expression. The results are representative of three independent replications.
- Fig. 5.
Upregulation of cdk5 immunoreactivity in rat hippocampus by chronic ECS treatment. A,Top, A representative immunoblot shows cdk5 levels in the hippocampus after sham or ECS treatment. Bottom, Levels of cdk5 immunoreactivity are given as arbitrary OD units and are expressed as the mean ± SEM (n = 8 animals in each treatment group). B, Top, A representative autoradiogram shows cdk5 AP-1-binding activity after sham or ECS treatment. Bottom, Levels of cdk5 AP-1-binding activity are given as arbitrary OD units and are expressed as the mean ± SEM (n = 8 animals in each treatment group). *p < 0.05 by Student'st test.
- Fig. 6.
Upregulation of tau phosphorylation in rat hippocampus by chronic ECS treatment. A, A representative immunoblot showing levels of phospho-tau proteins after sham or ECS treatment. B–F, Levels of phospho-tau, in arbitrary OD units, for each tau isoform ± SEM (n = 3). *p < 0.05 by Student's t test.
- Fig. 7.
Regulation of p35 and p25 immunoreactivity in rat hippocampus by chronic ECS treatment. A, A representative immunoblot shows p35 and p25 levels after sham or chronic ECS treatment. B, Levels of p35 and p25 immunoreactivity are given as arbitrary OD units and are expressed as the mean ± SEM (n = 8 animals in each treatment group). *p < 0.05 by Student'st test.
Tables
- Table 1.
Analysis of gene expression profiles in the hippocampus of inducible ΔFosB-expressing transgenic mice
Gene GenBank accession number % Regulation FosB x14897 467% ATP-dependent DNA helicase II x66323 135% Somatostatin receptor 2 m181832 102% Caspase-11 u59463 92% PCNA x53068 87% Relaxin z27088 83% Translin x81464 83% DNA ligase III u66058 79% MLH1 DNA mismatch repair protein u59883 77% Ung1 x99018 68% Oxidative stress-induced protein u40930 67% Glutathione S-transferase Pi 1 d30687 67% MHR23B x92411 67% Cdk5 d29678 61% DNA excision repair protein ERCC5 d16306 61% Ets-related Sap1A z36885 58% IL-10 receptor l12120 55% Bax l22472 51% RIP cell death protein u25995 51% Ubiquitin-conjugated enzyme x96859 51% PI3 kinase p110 u03279 −76% PI3 kinase p85 m60651 −76% Tie 2 proto-oncogene s67051 −77% Cyclin C u62638 −77% Myeloblastin, serine protease u43525 −77% IL-6 receptor gp130 m83336 −78% 5-HT 1b z11597 −79% Leukocyte adhesion LFA-1 x14951 −79% GABA-A transporter 3 l04663 −79% PAX-8 x57487 −80% Desmocolin 2 l33779 −81% 5-HT 2 s49542 −82% Interferon inducible protein 1 u19119 −84% Kruppel-like factor u25096 −86% PhosphorImager analysis of gene expression profiles of the hippocampus of mice expressing ΔFosB or not expressing ΔFosB revealed 34 genes that were upregulated or downregulated by ΔFosB by >50%. The results are representative of three independent determinations.
IL, Interleukin; LFA, leukocyte function-associated antigen; PI3, phosphatidylinositol 3; PCNA, proliferating cell nuclear antigen; MHR23B, Rad23 UV excision repair protein homologue; ERCC5, DNA excision repair protein; PAX, paired box protein; MLH1, MLH1 DNA mismatch repair protein.
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