|ognizant Communication Corporation|
VOLUME 10, NUMBER 4
Gene Expression, Vol. 10, pp. 137-152
1052-2166/02 $20.00 + .00
Copyright © 2002 Cognizant Comm. Corp.
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ZAS: C2H2 Zinc Finger Proteins Involved in Growth and Development
Departments of Molecular and Cellular Biochemistry, Internal Medicine, and Molecular Virology, Immunology and Medical Genetics, The Ohio State University, and College of Medicine and Public Health, Columbus, OH 43210
A ZAS gene encodes a large protein with two separate C2H2 zinc finger pairs that independently bind to specific DNA sequences, including the kB motif. Three paralogous mammalian genes, ZAS1, ZAS2, and ZAS3, and a related Drosophila gene, Schnurri, have been cloned and characterized. The ZAS genes encode transcriptional proteins that activate or repress the transcription of a variety of genes involved in growth, development, and metastasis. In addition, ZAS3 associates with a TNF receptor-associated factor to inhibit NF-kB- and JNK/SAPK-mediated signaling of TNF-a. Genetic experiments show that ZAS3 deficiency leads to proliferation of cells and tumor formation in mice. The data suggest that ZAS3 is important in controlling cell growth, apoptosis, and inflammation. The potent vasoactive hormone endothelin and transcription factor AP2 gene families also each consist of three members. The ZAS, endothelin, and transcription factor AP2 genes form several linkage groups. Knowledge of the chromosomal locations of these genes provides valuable clues to the evolution of the vertebrate genome.
Key words: ZAS; Separate C2H2 zinc finger pairs; TNF signaling; Endothelin; TFAP2; Evolution; Tumorigenesis; Homologous gene clusters; Thymocyte differentiation; Growth control
Address correspondence to Dr. Lai-Chu Wu, Davis Medical Center, Room S2077, Department of Internal Medicine, The Ohio State University, 480 West Ninth Avenue, Columbus, OH 43210. Tel: (614) 293-3042; Fax: (614) 293-5631; E-mail: email@example.com
Role of Mitogen-Activated Protein Kinases and Protein Kinase C in Regulating Low-Density Lipoprotein Receptor Expression
Kamal D. Mehta
Department of Molecular and Cellular Biochemistry, Ohio State University College of Medicine and Public Health, 1645 Neil Avenue, Columbus, OH 43210
The cell signaling pathways that culminate in induction of low-density lipoprotein (LDL) receptor transcription in response to a variety of extracellular and intracellular signals are beginning to be defined. Evidence is accumulating that LDL receptor transcription is under complex regulation and that a major pathway of induction by cytokines, growth factors, anisomycin, and phorbol esters involves the extracellular/mitogen-activated protein kinase (p42/44MAPK) cascade. In fact, degree of p42/44MAPK activation determines the extent of LDL receptor induction. The suppression of LDL receptor expression by stress-activated p38MAPK via p42/44MAPK provides a potential mechanism for stress-induced hypercholesterolemia observed in humans and animals. Moreover, endogenous signals such as cholesterol regulate LDL receptor transcription through a different signaling cascade involving protein kinase Ce isoform (PKCe). The ability of cholesterol to directly bind PKC\GK\e in an isoform-specific manner strongly supports its role in sensing the cellular cholesterol levels. The emerging picture from the above studies is that regulation of LDL receptor transcription results from the activity of a number of interlinked regulatory molecules and pathways, rather than from a single linear series of events. These studies will provide the necessary framework for understanding differential responses within human populations to atherosclerosis following high-fat/cholesterol diet. This information may also provide new strategies to modulate specific gene expression with the hope to develop novel therapies for the treatment of hypercholesterolemia.
Key words: p42/44MAPK; p38MAPK; Protein kinase C; LDL receptor; Transcriptional regulation; Hepatic cells
Address correspondence to Kamal D. Mehta, Department of Molecular and Cellular Biochemistry, Ohio State University College of Medicine and Public Health, Columbus, OH 43210. Tel: (614) 688-8451; Fax: (614) 292-4118; E-mail: firstname.lastname@example.org
Profiling of Acyl-CoA Oxidase-Deficient and Peroxisome Proliferator Wy14,643-Treated Mouse Liver Protein by Surface-Enhanced Laser Desorption/Ionization ProteinChip® Biology System
Ruiyin Chu,1 Weihua Zhang,3 Hanjo Lim,1 Anjana V. Yeldandi,2 Chris Herring,1 Laura Brumfield,1 Janardan K. Reddy,2 and Matthew Davison1
1Department of Functional Genomics, Aventis Pharmaceuticals,
Inc., P.O. Box 6800, Bridgewater, NJ 08807
2Department of Pathology, Northwestern University Medical School, 303 E. Chicago Ave, Chicago, IL 60611
3Ciphergen Biosystems, Inc., 6611 Dumbarton Circle, Fremont, CA 94555
Peroxisome proliferators induce hepatic peroxisome proliferation and hepatocellular carcinomas in rodents. These chemicals increase the expression of the peroxisomal b-oxidation pathway and the cytochrome P-450 4A family, which metabolizes lipids, including fatty acids. Mice lacking fatty acyl-CoA oxidase (AOX-/-), the first enzyme of the peroxisomal b-oxidation system, exhibit extensive microvesicular steatohepatitis, leading to hepatocellular regeneration and massive peroxisome proliferation. To investigate proteins involved in peroxisome proliferation, we adopted a novel surface-enhanced laser desorption/ionization (SELDI) ProteinChip technology to compare the protein profiles of control (wild-type), AOX-/-, and wild-type mice treated with peroxisome proliferator, Wy-14,643. The results indicated that the protein profiles of AOX-/- mice were similar to the wild-type mice treated with Wy14,643, but significantly different from the nontreated wild-type mice. Using four different ProteinChip Arrays, a total of 40 protein peaks showed more than twofold changes. Among these differentially expressed peaks, a downregulated peak was identified as the major urinary protein in both AOX-/- and Wy14,643-treated mice by SELDI. The identification of MUP was further confirmed by two-dimensional electrophoresis and liquid chromatography coupled tandem mass spectrometry (LC-MS-MS). This SELDI method offers several technical advantages for detection of differentially expressed proteins, including ease and speed of screening, no need for chromatographic processing, and small sample size.
Key words: ProteinChip Array; SELDI; Mass spectrometry; Peroxisome proliferator; Peroxisome proliferator-activated receptor; Acyl-CoA oxidase; Major urinary protein
Address correspondence to Ruiyin Chu, Ph.D., Department of Functional Genomics, Aventis Pharmaceuticals, Inc., Mail Code G303A, P.O. Box 6800, Bridgewater, NJ 08807. Tel: (908) 231-4917; Fax: (908) 231-2707; E-mail: email@example.com
Mammalian Resistance to Oxidative Stress: A Comparative Analysis
Toshihide Suzuki,1 Douglas R. Spitz,1 Purvee Gandhi,3 H. Y. Lin,4 and Dana R. Crawford3
1Laboratory of Forensic Chemistry, Faculty of Pharmaceutical
Sciences, Teikyo University, 1091-1 Sagamiko-machi, Tsukui-gun, Kanagawa
2Free Radical and Radiation Biology Program, Department of Radiation Oncology, The University of Iowa, Iowa City, IA 52242
3Center for Immunology and Microbial Disease, The Albany Medical College, Albany, NY 12208
4Center for Cell Biology and Cancer Research, The Albany Medical College, Albany, NY 12208
Changes in gene expression represent a major protective mechanism, and enforced overexpression of individual genes has been shown to protect cells. However, no large-scale comparison of genes involved in mammalian oxidative stress protection has yet been described. Using filter microarray and restriction fragment differential display technology, hydrogen peroxide (H2O2)-resistant variants of hamster HA-1 fibroblasts and human HL-60 promyelocytes were found to possess a surprising lack of commonality in specific modulated genes with the single exception of catalase, supporting the hypothesis that catalase overexpression is critical for resistance to H2O2. Comparison of two cell lines from the same species (hamster) selected with an exogenous oxidative stressing agent (H2O2) and an endogenous metabolic oxidative stressing agent (95% O2) also revealed little commonality in modulation of specific mRNAs with the exception of glutathione S-transferase enzymes and catalase. Acute oxidative stress in HL-60 led to the modulation of a limited subset of the genes associated with chronic oxidative stress resistance. Overall, these results suggest that mammalian resistance to oxidative and perhaps other stress does not require a significant number of common genes but rather only a limited number of key genes (e.g., catalase in our model systems) in combination with others that are cell type and stress agent specific.
Key words: Oxidative stress; Hydrogen peroxide; Chronic resistance; HA-1; HL-60; Catalase; Oxygen toxicity; Microarray
Address correspondence to Dana R. Crawford, Ph.D., Center for Immunology and Microbial Disease MC-151, The Albany Medical College, Albany, NY 12208. Tel: (518) 262-6652; Fax: (518) 262-6161; E-mail: firstname.lastname@example.org
Novel Binding of GTP to the Phosphoprotein (P) of Vesicular Stomatitis Virus
Manjula Mathur and Amiya K. Banerjee
Department of Virology, Lerner Research Institute-NN10, The Cleveland Clinic Foundation, Cleveland, OH 44195
The phosphoprotein (P) of vesicular stomatitis virus (VSV) is a subunit of the RNA polymerase (L) that transcribes the negative strand genome RNA into mRNAs both in vitro and in vivo. We have previously shown that the P protein of VSV, expressed in E. coli, is biologically inactive unless phosphorylated at specific serine residues by cellular casein kinase II (CKII). In the present study we present evidence that the P protein, in addition to being phosphorylated, binds covalently to GTP only when it is phosphorylated. Competition experiments show that ATP, ADP, GTP, and GDP can compete for the binding site(s) of GTP but not AMP, GMP, CTP, or UTP. Interestingly, once GTP is bound to P protein it cannot be displaced by unlabeled GTP. The GTP binding site has been mapped within the domain where the phosphorylation of P protein by CKII occurs. Finally, we show that phosphorylation negative P mutants P3A (P60A, P62A, P64A), P3E (P60E, P62E, P64E), and P3R (P60R, P62R, P64R) failed to bind to GTP, indicating that phosphorylation of P is indeed essential for binding to GTP. Although the precise role of binding of GTP to P is unclear, it appears that phosphorylation of P may initiate a structural change within the P protein allowing GTP to bind, thus manifesting biological function to the transcription factor.
Key words: Vesicular stomatitis virus; P protein; Phosphorylation; GTP binding
Address correspondence to Amiya K. Banerjee, Department of Virology, NN10, Lerner Research Institute, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195. Tel: (216) 444-0625; Fax: (216) 444-2998; E-mail: email@example.com