Graciela Unguez
Professor of Biology
gunguez@nmsu.edu
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- BS - University of California at Los Angeles 1987
- Ph.D. - University of California at Los Angeles 1994
- Postdoctoral, University of Texas at Austing 1995-19999
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Research Interests
- Developmental Biology
- Neuroscience
- Motor Systems
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A fundamental question in developmental
biology is how intrinsic and extrinsic factors influence the phenotype
expressed by individual cells. This tissue is particularly pertinent
to excitable cells like muscle fibers, which express an extreme
diversity of biochemical, morphological, and physiological characteristics.
Currently, my lab studies the electromotor system of electric
fish. In all electric fish, some skeletal muscle fibers lose their
contractile apparatus and convert their phenotype into non-contractile
electrocytes, i.e., electrogenic cells of the electric organ (EO).
How the genes coding for a select number of muscle-specific proteins
are down-regulated while others are maintain and novel genes are
up-regulated, is an intriguing problem in the control of muscle
and EO phenotype. Interestingly, EOs are formed from a large variety
of skeletal muscles, including
extraocular, brachial, pectoral, axial, and tail muscles in fish
representing at least six independently evolved groups. The mechanisms
by which only certain skeletal muscles undergo such phenotypic
conversion remain to be determined. Furthermore, electrocytes
are innervated by specialized electromotoneurons (EMNs) that derive
from spinal and cranial motoneurons. How electrocytes and EMNs
have evolved from their precursor cells to form a functional electromotor
system is unknown. Ultimately, our goal is to understand the mechanisms
underlying the differentiation and maintenance of phenotypic fates
among muscle-derived cells and motoneuronal cell types of the
electromotor system in a variety of distantly related species.
My lab uses a multi-disciplinary approach that combines a range
of molecular, anatomical, microscopical, and in vitro techniques
to address these research goals.
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Ultrastructural Properties of electrocytes
and myocytes |
Publications that
represent the work I do:
- Unguez, G.A. and Zakon, H.H. (1998).
Phenotypic conversion of distinct muscle fiber populations to
electrocytes in a weakly electric fish. Journal of Comparative
Neurology. 399: 20-34.
- Unguez, G.A. and Zakon, H.H. (1998)
Re-expression of myogenic proteins in mature electric organ following
removal of neural input. Journal of Neuroscience. 18: 9924-9935.
- Zakon, H.H. and
Unguez, G.A. (1999). Invited Review: Development and regeneration
of the electric organ. Journal of Experimental Biology. 202:
1427-1434.
- Unguez G.A., Talmadge R.J., Dalponte
D., Roy R.R. and Edgerton V.R. (2000). Myosin heavy chain isoforms
in developing cat hindlimb muscles. Cells, Tissues and Organs.
167 (2-3): 138-152.
- Smith G.T., Unguez
G..A. and Reinauer R.M. (2002). NADPH-diphorase activity
and nitric oxide synthase-like immunoreactivity colocalize in
the electromotor system of four species of gymnotiform fish.
Brain, Behavior and Evolution. 58:122-136.
- Unguez GA and Zakon
HH (2002). Skeletal muscle transformation into electric organ
in S. macrurus depends on innervation. Journal of Neurobiology.
In Press
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Last updated: July 19, 2002