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John Tower
Associate Professor of Biological Sciences
Contact Information
Office: RRI 219C
Phone: (213)740-5384
E-mail:
jtower@usc.edu
LINKS
Curriculum Vitae
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Biographical Sketch
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John Tower received his PhD in 1988 from The Johns Hopkins University School of Medicine, Biochemistry, Cellular, and Molecular Biology Training Program, where he worked under the direction of Dr. Barbara Sollner-Webb on the topic of rDNA transcriptional regulation. He subsequently undertook postdoctoral training with Dr. Allan C. Spradling, at the Department of Embryology, Carnegie Institution of Washington, in Baltimore, where he began ongoing studies on Drosophila P element mutagenesis and chorion gene amplification. In 1991 he joined the faculty in the Department of Biological Sciences, University of Southern California, in what is now the Molecular and Computational Biology Program. Dr. Tower has been investigating the molecular genetics of aging in Drosophila since 1990, with a particular emphasis on transgenic technologies, hsps and superoxide dismutase.
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Education
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 Ph.D. Biochemistry, Cellular and Molecular Biology Training Program, The Johns Hopkins University School of Medicine, 1988
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Postdoctoral Training
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Postdoctoral fellow, The Carnegie Institution of Washington, Dept of Embryology, Baltimore, 1988-1991
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Description of Research
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Summary Statement of Research Interests
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Professor Tower's research primarily focuses on the following two areas: the molecular genetics of aging in Drosophila and Drosophila chorion gene amplification. He is taking two approaches to his research on aging, the first of which identifies genes that directly regulate life span. His current emphasis with these techniques is to test candidate genes involved in regulating oxidative stress responses, DNA repair, and nuclear-mitochondrial signaling. He is particularly interested in how the post-mitotic muscle and nerve cells of the adult maintain function during aging, and how stem cells populations are maintained in the ovary. The second general approach he uses is studying the regulation of heat shock gene expression as a function of age, in particular the hsp70 and hsp22 genes. He is pursuing a detailed analysis of the transcriptional and posttranscriptional regulation of the Drosophila hsp70 and hsp22 genes as a model for this species-general aspect of aging.
In his investigation of chorion gene amplification, Professor Tower has cloned and characterized two amplification trans-regulators, k43 and chiffon, and found that they are related to origin regulatory proteins in yeasts, ORC2 and Dbf4 respectively. Prior analysis of cis-sequence elements and their relationship to origins was hampered by severe chromosomal position effects. He found that flanking the ends of transgenic constructs with transcriptional insulator elements, called "Suppressor of Hairy-wing protein binding sites" (SHWBSs) protected the constructs from position effects. The data implicated chromatin structure in origin regulation, and provided a powerfully improved assay. Using such buffered constructs he has been able to analyze cis-sequence requirements and functions in detail. Professor Tower found that functionally distinct, sequence-specific replicator and origin elements are required for amplification.
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Research Keywords
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aging, hsp70, hsp22, oxidative damage, ROS, life span, stem cells, replicative senescence, DNA replication origins, drosophila chorion gene amplification, replicator, follicle cells, biological scienc
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Research Specialties
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Aging and Development Biology, DNA replication, Signal Transduction and Gene Regulation
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Publications
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Journal Article
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Tower, J. G., Ford, D., Hoe, N., Landis, G. N., Tozer, K., Luu, A., Bhole, D., Badrinath, A., Tower, J.
(2007).
Alteration of Drosophila life span using conditional, tissue-specific expression of transgenes triggered by doxycyline or RU486/Mifepristone. Exp Gerontol.
Vol. 42, pp. 483-97.
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Tower, J. G., Ren, C., Webster, P., Finkel, S. E., Tower, J.
(2007).
Increased internal and external bacterial load during Drosophila aging without life-span trade-off. Cell Metab.
Vol. 6, pp. 144-52.
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Tower, J. G., Tower, J.
(2006).
The murmur of old broken heartstrings. Cell Metab.
Vol. 4, pp. 101-3.
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Tower, J. G., Tower, J.
(2006).
Sex-specific regulation of aging and apoptosis. Mech Ageing Dev.
Vol. 127, pp. 705-18.
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Tower, J. G., Landis, G. N., Tower, J.
(2005).
Superoxide dismutase evolution and life span regulation. Mech Ageing Dev.
Vol. 126, pp. 365-79.
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Tower, J. G., Waskar, M., Li, Y., Tower, J.
(2005).
Stem Cell Aging in the Drosophila Ovary. AGE.
Vol. 27
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Tower, J. G., Tower, J.
(2004).
There's a problem in the furnace. Sci Aging Knowledge Environ.
Vol. 2004, pp. pe1.
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Tower, J. G., Bhole, D., Allikian, M. J., Tower, J.
(2004).
Doxycycline-regulated over-expression of hsp22 has negative effects on stress resistance and life span in adult Drosophilamelanogaster. Mech Ageing Dev.
Vol. 125, pp. 651-63.
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Tower, J. G., Tower, J.
(2004).
Developmental Gene Amplification and Origin Regulation. Annu Rev Genet.
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Tower, J. G., Landis, G. N., Abdueva, D., Skvortsov, D., Yang, J., Rabin, B. E., Carrick, J., Tavaré, S., Tower, J.
(2004).
Similar gene expression patterns characterize aging and oxidative stress in Drosophila melanogaster. Proc Natl Acad Sci U S A.
Vol. 101, pp. 7663-8.
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Tower, J. G., Sun, J., Molitor, J., Tower, J.
(2004).
Effects of simultaneous over-expression of Cu/ZnSOD and MnSOD on Drosophila melanogaster life span. Mech Ageing Dev.
Vol. 125, pp. 341-9.
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Tower, J. G., Zhang, H., Tower, J.
(2004).
Sequence requirements for function of the Drosophila chorion gene locus ACE3 replicator and ori-beta origin elements. Development.
Vol. 131, pp. 2089-99.
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Tower, J. G., Landis, G. N., Bhole, D., Tower, J.
(2003).
A search for doxycycline-dependent mutations that increase Drosophila melanogaster life span identifies the VhaSFD, Sugar baby, filamin, fwd and Cctl genes. Genome Biol.
Vol. 4, pp. R8.
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Tower, J. G., Tower, J.
(2002).
Setting a trap for aging-related genes in Drosophila. Sci Aging Knowledge Environ.
Vol. 2002, pp. pe15.
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Tower, J. G., Sun, J., Folk, D., Bradley, T. J., Tower, J.
(2002).
Induced overexpression of mitochondrial Mn-superoxide dismutase extends the life span of adult Drosophila melanogaster. Genetics.
Vol. 161, pp. 661-72.
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Tower, J. G., Allikian, M. J., Deckert-Cruz, D., Rose, M. R., Landis, G. N., Tower, J.
(2002).
Doxycycline-induced expression of sense and inverted-repeat constructs modulates phosphogluconate mutase (Pgm) gene expression in adult Drosophila melanogaster. Genome Biol.
Vol. 3, pp. research0021.
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Tower, J. G., Landis, G., Bhole, D., Lu, L., Tower, J.
(2001).
High-frequency generation of conditional mutations affecting Drosophila melanogaster development and life span. Genetics.
Vol. 158, pp. 1167-76.
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Tower, J. G., Lu, L., Zhang, H., Tower, J.
(2001).
Functionally distinct, sequence-specific replicator and origin elements are required for Drosophila chorion gene amplification. Genes Dev.
Vol. 15, pp. 134-46.
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Tower, J. G., Kurapati, R., Passananti, H. B., Rose, M. R., Tower, J.
(2000).
Increased hsp22 RNA levels in Drosophila lines genetically selected for increased longevity. J Gerontol A Biol Sci Med Sci.
Vol. 55, pp. B552-9.
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Tower, J. G., Tower, J.
(2000).
Transgenic methods for increasing Drosophila life span. Mech Ageing Dev.
Vol. 118, pp. 1-14.
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Tower, J. G., Wheeler, J. C., King, V., Tower, J.
(1999).
Sequence requirements for upregulated expression of Drosophila hsp70 transgenes during aging. Neurobiol Aging.
Vol. 20, pp. 545-53.
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Tower, J. G., Landis, G., Tower, J.
(1999).
The Drosophila chiffon gene is required for chorion gene amplification, and is related to the yeast Dbf4 regulator of DNA replication and cell cycle. Development.
Vol. 126, pp. 4281-93.
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Tower, J. G., King, V., Tower, J.
(1999).
Aging-specific expression of Drosophila hsp22. Dev Biol.
Vol. 207, pp. 107-18.
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Tower, J. G., Sun, J., Tower, J.
(1999).
FLP recombinase-mediated induction of Cu/Zn-superoxide dismutase transgene expression can extend the life span of adult Drosophila melanogaster flies. Mol Cell Biol.
Vol. 19, pp. 216-28.
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Tower, J. G., Bieschke, E. T., Wheeler, J. C., Tower, J.
(1998).
Doxycycline-induced transgene expression during Drosophila development and aging. Mol Gen Genet.
Vol. 258, pp. 571-9.
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Tower, J. G., Bhui-Kaur, A., Goodman, M. F., Tower, J.
(1998).
DNA mismatch repair catalyzed by extracts of mitotic, postmitotic, and senescent Drosophila tissues and involvement of mei-9 gene function for full activity. Mol Cell Biol.
Vol. 18, pp. 1436-43.
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Tower, J. G., Landis, G., Kelley, R., Spradling, A. C., Tower, J.
(1997).
The k43 gene, required for chorion gene amplification and diploid cell chromosome replication, encodes the Drosophila homolog of yeast origin recognition complex subunit 2. Proc Natl Acad Sci U S A.
Vol. 94, pp. 3888-92.
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Tower, J. G., Lu, L., Tower, J.
(1997).
A transcriptional insulator element, the su(Hw) binding site, protects a chromosomal DNA replication origin from position effects. Mol Cell Biol.
Vol. 17, pp. 2202-6.
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Tower, J. G., Tower, J.
(1996).
Aging mechanisms in fruit files. Bioessays.
Vol. 18, pp. 799-807.
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Tower, J. G., Wheeler, J. C., Bieschke, E. T., Tower, J.
(1995).
Muscle-specific expression of Drosophila hsp70 in response to aging and oxidative stress. Proc Natl Acad Sci U S A.
Vol. 92, pp. 10408-12.
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Tower, J. G., Tower, J., Kurapati, R.
(1994).
Preferential transposition of a Drosophila P element to the corresponding region of the homologous chromosome. Mol Gen Genet.
Vol. 244, pp. 484-90.
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Tower, J. G., Tower, J., Karpen, G. H., Craig, N., Spradling, A. C.
(1993).
Preferential transposition of Drosophila P elements to nearby chromosomal sites. Genetics.
Vol. 133, pp. 347-59.
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Tower, J. G., Underwood, E. M., Briot, A. S., Doll, K. Z., Ludwiczak, R. L., Otteson, D. C., Tower, J., Vessey, K. B., Yu, K.
(1990).
Genetics of 51D-52A, a region containing several maternal-effect genes and two maternal-specific transcripts in Drosophila. Genetics.
Vol. 126, pp. 639-50.
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Tower, J. G., Tower, J., Sollner-Webb, B.
(1987).
Transcription of mouse rDNA is regulated by an activated subform of RNA polymerase I. Cell.
Vol. 50, pp. 873-883.
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Tower, J. G., Tower, J., Culotta, V., Sollner-Webb, B.
(1986).
The factors and sequences that direct rDNA transcription and their relationship to the stable transcription complex. Molecular and Cellular Biology.
Vol. 6, pp. 3451-3462.
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Other
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Tower, J. G., Ford, D., Tower, J.
(2006).
Genetic manipulation of life span in. Elsevier.
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Tower, J. G., Allikian, M., Tower, J.
(2000).
Drosophila studies. Academic Pres.
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Service to the Profession
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Editorships and Editorial Boards
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Editorial board, BMC Gerontology, 2006-2007
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Editorial board, Experimental Gerontology, 2006-2007
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Editorial board, Gerontology, 2006-2007
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