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Tory Herman

Tory Herman

Associate Professor, Biology
Member, IMB

Ph.D., Massachusetts Institute of Technology
B.A., Harvard-Radcliffe College

Email
Office: 276A Streisinger Hall
Office Phone: 541-346-5043
Lab: 275 Streisinger Hall
Lab Phone: 541-346-2886

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Research Interests

Brain function, from sensory perception to behavior, is derived from the pattern and properties of the synaptic connections among hundreds (in C. elegans), hundreds of thousands (in Drosophila), or even billions (in humans) of individual neurons. I am interested in three broad but related questions: by what cellular and molecular mechanisms do neurons form synapses only with the correct neuronal partners, how are the specialized pre- and post-synaptic structures assembled into functional connections, and how are these connections organized to form functional neural circuits?

I propose to address these questions using the Drosophila visual system. Fly photoreceptor neurons (R cells) face tasks of target selection and synapse formation similar to those faced by vertebrate neurons: each class of R cell makes synapses that are restricted to a different layer of the underlying optic ganglia; the topographical arrangement of the R cell synapses within each layer recapitulates the arrangement of their cell bodies in the retina; and this final retinotopic pattern of synapses is achieved by interactions among neighboring R cells.

I have begun the identification and analysis of genes required for synaptic target selection by a subset of R neurons, the R7s, taking advantage of a unique combination of powerful tools: the ability to create homozygous mutant R7s in an otherwise wild-type animal; to select mosaic animals with non-functional R7s (the primary sensors of UV light) by means of a robust behavioral assay (a failure to phototax toward UV in preference to green light); and to analyze histologically the synaptic connections of mutant R7s in an otherwise wild-type animal. This novel screen has successfully identified genes required for formation of R7 synapses in the correct target layer and genes required for restriction of R7 synapses to discrete, retinotopically correct targets within that layer. I propose to continue to use these methods to complete a molecular understanding of R7 target selection and synaptogenesis.

Synapse formation involves bidirectional signaling between axon and target to coordinate the assembly of pre- and post-synaptic specializations. The identities of the cells that cue R7s to terminate in the correct layer are unknown, as are the identities of the cells upon which R7s synapse in the adult (it is unclear at this point whether these two categories of cells will be the same). I propose to develop the tools to identify and genetically manipulate the R7 targets as easily as it is now possible to manipulate R7. Such tools will allow the identification of genes required post-synaptically for R7 target selection and synaptogenesis and may allow us ultimately to dissect the neural circuit for the discrimination of UV from other colors of light.

Recent publications

(pulled from pubmed)

Recent publications

(pulled from pubmed)

Loss of syd-1 from R7 neurons disrupts two distinct phases of presynaptic development.
Holbrook S, Finley JK, Lyons EL, Herman TG
The Journal of neuroscience : the official journal of the Society for Neuroscience 2012
Coordinate control of synaptic-layer specificity and rhodopsins in photoreceptor neurons.
Morey M, Yee SK, Herman T, Nern A, Blanco E, Zipursky SL
Nature 2008
An isoform-specific allele of Drosophila N-cadherin disrupts a late step of R7 targeting.
Nern A, Nguyen LV, Herman T, Prakash S, Clandinin TR, Zipursky SL
Proceedings of the National Academy of Sciences of the United States of America 2005
Identification of a Wnt/Dvl/beta-Catenin --> Pitx2 pathway mediating cell-type-specific proliferation during development.
Kioussi C, Briata P, Baek SH, Rose DW, Hamblet NS, Herman T, Ohgi KA, Lin C, Gleiberman A, Wang J, Brault V, Ruiz-Lozano P, Nguyen HD, Kemler R, Glass CK, Wynshaw-Boris A, Rosenfeld MG
Cell 2002
Temporal regulation of a paired-like homeodomain repressor/TLE corepressor complex and a related activator is required for pituitary organogenesis.
Dasen JS, Martinez Barbera JP, Herman TS, Connell SO, Olson L, Ju B, Tollkuhn J, Baek SH, Rose DW, Rosenfeld MG
Genes & development 2001
Drosophila LAR regulates R1-R6 and R7 target specificity in the visual system.
Clandinin TR, Lee CH, Herman T, Lee RC, Yang AY, Ovasapyan S, Zipursky SL
Neuron 2001
Tbx19, a tissue-selective regulator of POMC gene expression.
Liu J, Lin C, Gleiberman A, Ohgi KA, Herman T, Huang HP, Tsai MJ, Rosenfeld MG
Proceedings of the National Academy of Sciences of the United States of America 2001
N-cadherin regulates target specificity in the Drosophila visual system.
Lee CH, Herman T, Clandinin TR, Lee R, Zipursky SL
Neuron 2001
Regulation of somatic growth by the p160 coactivator p/CIP.
Wang Z, Rose DW, Hermanson O, Liu F, Herman T, Wu W, Szeto D, Gleiberman A, Krones A, Pratt K, Rosenfeld R, Glass CK, Rosenfeld MG
Proceedings of the National Academy of Sciences of the United States of America 2000
Three proteins involved in Caenorhabditis elegans vulval invagination are similar to components of a glycosylation pathway.
Herman T, Horvitz HR
Proceedings of the National Academy of Sciences of the United States of America 1999
sqv mutants of Caenorhabditis elegans are defective in vulval epithelial invagination.
Herman T, Hartwieg E, Horvitz HR
Proceedings of the National Academy of Sciences of the United States of America 1999
Mutations that perturb vulval invagination in C. elegans.
Herman T, Horvitz HR
Cold Spring Harbor symposia on quantitative biology 1997