Boston University Department of Biology

Faculty Profiles

Current Research

Research in this laboratory focuses on the biosynthesis and actions of estradiol. In tissues where aromatase (cytochrome P450 aromatase, estrogen synthetase) and estrogen receptors (ER) are colocalized, estradiol has discrete, local actions (paracrine, autocrine) that differ qualitatively and quantitatively from those exerted by the circulating hormone (endocrine). We are investigating the structure, function, regulation and evolution of genes encoding aromatase (Cyp19) and ER (Esr) in neural tissues and the physiological and developmental consequences of estrogen formation in specific cells and circuits of the brain and retina. A component of the project is to define t the role of different ER genes and their splice variants in mediating estrogen actions in different tissue types and developmental stages, and to determine how estrogen-like chemicals in the environment impact normal endocrine and neuroendocrine processes of physiology and development. We use a wide range of animal models from fish to mammals and rely primarily on methods of cell biology (tissue culture, light and electron microscopy, image analysis), protein and steroid biochemistry (enzymology, SDS-PAGE and immunoblot analysis), and molecular biology (cDNA and gene cloning, PCR-based methods of RNA & DNA analysis).

Courses Taught

• BI 554 Neuroendocrinology
• BI 111 Brain, Hormones and Behavior

Selected Publications

• Callard GV, Greytak SR, Novillo A, Cotter KA, Meyer R (2012). Brain Aromatase in Fishes. In: Balthazart J, Ball G (eds), Brain Aromatase, Estrogens and Behavior, Oxford Univ Press, pp. 2-42.
• Callard GV, Tarrant A, Novillo A, Yacci P, Ciaccia L, Vajda S, Chuang G-Y, Kozakov D, Greytak SR, Sawyer S, Hoover C, Cotter K. (2011). Evolutionary origins of the estrogen signaling system: insights from amphioxus. J Steroid Biochem Mol Biol 127: 176-188.
• McCurley A, Callard GV (2010). Time course analysis of gene expression patterns in zebrafish eye during optic nerve regeneration. J Exptl Neurosci 4:17-33
• Greytak SR, Tarrant A, Nacci D, Hahn ME, Callard GV (2010). Estrogen responses in killifish (Fundulus heteroclitus) from polluted and unpolluted environments are site- and gene-specific. Aquatic Toxicol. 99(2): 291–299.
• McCurley A, Callard GV (2008). Characterization of housekeeping genes in zebrafish: male-female differences and effects of tissue type, developmental stage and chemical treatment. BMC Molecular Biology 9:102.
• Greytak SR, Champlin D, Callard GV. (2005). Isolation and characterization of two cytochrome P450 aromatase forms in killifish (Fundulus heteroclitus): Differential expression in fish from polluted and unpolluted environments. Aquatic Toxicology 71, 371-389.
• Kishida M, Callard GV. (2001). Distinct cytochrome P450 aromatase isoforms in zebrafish (Danio rerio) brain and ovary are differentially programmed and estrogen regulated during early development. Endocrinology. Feb; 142(2), 740-50.
• Tchoudakova A, Callard GV. (1998). Identification of multiple CYPl9 genes encoding different cytochrome P450 aromatase isozymes in brain and ovary. Endocrinology 139, 2179-2189.