Graciela Unguez
Title: Associate Professor
Research area: Developmental Biology, Neuroscience,
Motor Systems
Office location: FH 461
Laboratory Location: FH 441
Email Address: gunguez@nmsu.edu
Office Phone: 575-646-7963
Lab Phone: 575-646-5250
Lab/Personal Webpage: http://biology-web.nmsu.edu/unguez/Unguez.htm
Education:
- Post-doctoral work: University of Texas at Austin
- PhD: University of California at Los Angeles
- MS: University of California at Los Angeles
- BS: University of California at Los Angeles
Research Interests:
A fundamental question in
developmental biology is how intrinsic and extrinsic factors influence
the phenotype expressed by individual cells. This issue is
particularly pertinent to excitable cells like muscle fibers which
express an extreme diversity of biochemical, morphological, and
physiological characteristics.
Currently, I am working on 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 maintained 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, my 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. I plan to use a multi-disciplinary
approach that combines a range of molecular, anatomical, microscopical,
and in vitro techniques to address these research goals.
Together, this research will: 1) reveal new insights on the
mechanisms regulating the expression of genes coding for a select
number of muscle-specific proteins; 2) determine the molecular and
cellular interactions between muscles and their nerves; 3) have broad
relevance including identification of mechanisms of tissue
transdifferentiation, and clinical importance to pathological
conditions caused by disease or injury where muscle development or
maintenance is compromised; and 4) shed light on an evolutionary
process: how neurons and their targets co-evolve.
Selected Publications:
- Unguez, G.A., Bodine-Fowler, S., Roy, R.R., Pierotti, D.J.. and
Edgerton, V.R. (1993). Evidence of incomplete neural
control of motor unit properties in cat tibialis anterior after
self-reinnervation. Journal of Physiology (London), 472:
103-25.
- Unguez, G.A., Roy, R.R., Pierotti, D.J., Bodine-Fowler, S. and
Edgerton, V.R. (1994). Further evidence of incomplete
neural control of motor unit properties after reinnervation.
American Journal of Physiology (Cell Phys.), 268: 527-534.
- Unguez, G.A., Roy, R.R. and Edgerton, V.R. (1996).
Absence of a redistribution of fiber types following reinnervation of
adult muscle. Muscle and Nerve, 19: 1320-1327.
- 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. (1998). Invited Review: Development and regeneration of the electric organ. Journal of Experimental Biology. Manuscript in press.