Biology Program

Penn State Erie, The Behrend College

Dr. James T. Warren Jr.

Associate Professor of Biology

Ph.D. Molecular Biology, Clemson University, Clemson, SC, 1990

B.S. Biology, Allegheny College, Meadville, PA, 1982

Teaching Interests:

Biology: Function and Development of Organisms - An introduction to the development and physiological processes of both plants and animals.

General Biochemistry - This course covers the flow of information and energy within organisms. Course topics include bioenergetics, metabolic and anabolic pathways, hormonal regulation and information pathways.

Animal Developmental Biology - An upper level course that covers embryology and the molecular mechanisms involved in animal differentiation and development.
Lower level courses have laboratories with problem oriented exercises that help develop analytical skills while illustrating the basic principles outlined in lecture. Upper level classes will emphasize class projects and student designed laboratory exercises that require application of knowledge aquired in the classroom.

Research Interests:

Molecular Mechanisms of Vertebrate Development using the zebrafish (Danio rerio) as a model system.  The zebrafish is rapidly becoming the model system of choice for developmental studies for many reasons.  Zebrafish are inexpensive and easy to maintain, and their eggs are exceptionally clear throughout early development.  These embryos develop rapidly and are experimentally manipulable by a number of cellular, molecular, and genetic techniques.  Several labs around the world have undertaken mutagenesis screens designed to identify genes essential in early development and there are now a large number of developmental mutants that are available for study.

Molecular Genetic Analysis of Folate Metabolism: Folic acid derivatives participate in the synthesis and utilization of one-carbon functional groups which are involved in amino acid and nucleotide metabolism. Folic acid has long been linked to neural tube defects (NTDs), although the precise mechanisms of this association have not been determined. In order to better understand the role of this vitamin in neuronal development, we have initiated a molecular genetic analysis of folate metabolism in the zebrafish (Danio rerio).

Axon Pathfinding: The vertebrate embryo sets up an extremely intricate network of neuronal connections during development.  Neurons extend long cylindrical processes called axons that are led by a motile sensory structure called the growth cone.  Many molecules expressed on the growth cone or its surrounding environment are thought to serve an instructive role, helping guide the growth cone to its proper target.  Cloning of these putative axon guidance molecules, analysis of their expression patterns in normal and mutant zebrafish, and misexpression of them during embryogenesis should allow us to determine their precise roles in neuronal development.

Zebrafish Transgenics: Determining the role an individual molecule plays in development often requires the misexpression of that molecule via transgenics and an analysis of any resultant phenotype.  To facilitate these transgenic studies, we have cloned regulatory regions of DNA called promoters from several different zebrafish genes that should give us constitutive, inducible, and tissue specific regulation of transgene expression. Characterization and refining of these promoters should provide invaluable tools for zebrafish transgenics.

Heat Shock Proteins: Heat shock proteins are a large family of molecules that are evolutionarily conserved from bacteria to man.  Involved in a number of processes involving protein-protein interactions, they have been found to interact with a number of key regulatory molecules in development.  We have cloned several of these heat shock protein genes, and are now looking at their patterns of expression during development and the molecular basis for the regulation of that expression.

Publication List:

1. Blechinger, S.R., Warren, J.T.Jr., Kuwada, J.Y. and Krone, P.H. Real time toxicity assessment in a stable line of trangenic zebrafish. (Accepted for publication in Environmental Health Perspectives,April 2002).

2. Scheer N., Riedl I., Warren J.T.Jr., Kuwada J.Y., Campos-Ortega J.A. A quantitative analysis of the kinetics of Gal4 activator and effector gene expression in the zebrafish. Mechanisms of Development (2002), Mar: 112(1-2), 9-14.

3. Blechinger, S.R., Evans, T.G., Tang, P.T., Kuwada, J.Y., Warren, J.T.Jr., and Krone, P.H. The heat-inducible zebrafish hsp70 gene is expressed during normal lense development under non-stress conditions. Mechanisms of Development (2002) 112, 213-215.

4. Lang, D.M., Warren J.T. Jr., Klisa, C. and Stuermer, C.A.O. Topographic Restriction of TAG-1 Expression in the Developing Retinotectal Pathway and Target Dependent Reexpression During Axon Regeneration. Molecular and Cellular Neuroscience(2001) 17, 398-414.

5. Halloran, M.C., Sato-Maeda, M., Warren JT Jr., Su, F., Lele, Z, Krone, P., Kuwada, JY and Shoji, W. Laser induced gene expression in specific cells of transgenic zebrafish. Development(2000) 127, 1953-1960.

6. Halloran, M.C., J.T. Warren Jr., F. Su, Z. Lele, P.H. Krone, and J.Y. Kuwada. Laser induced gene expression in specific cells of transgenic zebrafish. Manuscript submitted to Development (June, 1999).

7. Warren JT Jr, Chandrasekhar A, Kanki JP, Rangarajan R , Furley AJ and Kuwada JY. Molecular cloning and developmental expression analysis of the zebrafish axonal glycoprotein similar to TAG-1. Mechanisms of Development, 1999, Feb;80(2):197-201.

8. Yee CS, Chandrasekhar A, Halloran MC, Shoji W, Warren JT Jr and Kuwada, JY. Molecular cloning, expression and activity of zebrafish Semaphorin Z1. (In press, Brain Research Bulletin, 1999).

9. Chandrasekhar A, Moens CB, Warren JT Jr, Kimmel CB and Kuwada, JY. Organization and mutational analysis of the hindbrain branchiomotor neurons of the zebrafish embryo. Development (1997)124, 2633-2644.

10. Chandrasekhar A, Warren JT Jr, Takahashi, K, Schauerte, HE,van Eeden FJM, Haffter, P and JY Kuwada. Role of sonic hedgehog in branchimotor neuron induction in zebrafish. Mechanisms of Development (1998), May, 76:101-115.

11. Warren JT Jr, Peacock ML, Rodriguez,L., and Fink JK. An MspI polymorphism in the human serotonin (5HT2) receptor gene (HTR2): Detection by DGGE and RFLP analysis. Human Molecular Genetics 1993 Mar;2(3):338.

12. Warren JT Jr, Peacock ML, and Fink JK. An RsaI polymorphism in the human serotonin (5HT1A) receptor gene (HTR1): Detection by DGGE and RFLP analysis. Human Molecular Genetics 1992 Dec;1(9):778.

13. Peacock ML, Murman DL, Sima AAF, Warren JT Jr., Roses AD, and Fink JK. Novel amyloid precursor protein gene mutation (codon 665 Asp) in a patient with late-onset Alzheimer's disease. Ann Neurol 1994 Apr;35(4):432-8.

14. Peacock ML,Warren JT Jr,Roses AD, and Fink,JK. Novel polymorphism in the A4-region of the amyloid precursor protein gene in a patient without Alzheimer's disease. Neurology 1993 Jun;43(6):1254-6.

15. Fink JK, Peacock ML, Warren JT Jr, and Prusiner SB. Detecting prion protein gene mutations by denaturing gradient gel electrophoresis. Hum Mutat 1994;4(1):42-50.

16. Fink JK, Warren JT Jr, Drury I, Murman D, and Peacock ML. Allele-specific sequencing confirms novel prion gene polymorphism in Creutzfeldt-Jakob disease. Neurology 1991,41(10): 1647-1650.

17. Smith TJ, Warren JT Jr, and Kline EL. Retinoic acid blockade of imidazole-induced tyrosinase expression in B16 melanoma cultures: similar effects of the active retinoid and triiodothyronine. Biochemical and Biophysical Research Communications 1989;162(1): 288-293.

18. Kline EL, Carland KC, Warren JT Jr, and Smith TJ. Effect of testosterone on imidazole-induced tyrosinase expression in B16 melanoma cell culture. Cancer Research 1988; 48:3586-3590.

Interested persons can reach me for information at:
Phone: 814-898-6986

This page was last updated 05 Sep 2004.