Magdalena Bezanilla
Assistant Professor
bezanilla@bio.umass.edu
Education
B.S., University of California, Santa Barbara, 1994
Ph.D., John's Hopkins School of Medicine, 2000
Postdoctoral
Salk Institute for Biological Studies, San Diego, 2000
Washington University, St Louis, 2000-2005
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Research Interests
My lab studies the molecular mechanisms behind plant cell growth. In particular
we are focusing on the mechanisms leading to the very polar and directed form
of growth known as tip growth. Tip growth is a fundamental form of growth throughout
all known plant taxa. The actin cytoskeleton provides the driving force for
tip growth in many cell types. However, the regulation of the dynamics of the
actin cytoskeleton in plant cells is an open question. We are investigating how
actin-binding proteins affect dynamics in the cell and how they regulate tip
growth.
We are studying these questions in two evolutionarily divergent plant model systems: a moss,
Physcomitrella patens, and an angiosperm, Arabidopsis thaliana. Physcomitrella is an excellent
organism for studying tip growth because the major colonizing growth tissue grows via tip growth
and its developmental pattern is quite simple compared to other land plants. Physcomitrella is also
the only known land plant that undergoes efficient homologous recombination which opens the possibility
for gene replacement studies as well as targeted knockouts. In addition my lab has developed a fast and
reliable transient RNA interference method allowing the possibility of analyzing loss-of-function
phenotypes for genes belonging to large gene families. By studying mutant phenotypes in moss, the
relatively simply model, we can dissect the molecular basis of the observed phenotypes at the cellular
level. This will direct our studies in Arabidopsis where development is relatively more complicated
and cellular defects are not as easily identifiable.
Current projects include understanding the cellular regulation of ADF, an important actin binding
protein, required for controlling actin dynamics. My work in Physcomitrella has shown that ADF is
essential for tip growth. Using molecular tools including complementation of null and knockdown
phenotypes, we will investigate how ADF is regulated in vivo and which form of regulation is relevant
for tip growth. We will study interactions between ADF and other proteins to begin to understand how
ADF-mediated actin dynamics is regulated in plant cells.
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Representative Publications
Bezanilla, M., Perroud, P-F, Pan, A., Klueh, P., and Quatrano, R.S. 2005. An RNAi System in Physcomitrella
patens with an Internal Marker for Silencing Allows for Rapid Identification of Loss of Function
Phenotypes. Plant Biology, 7: 251-257.
Bezanilla, M., Pan, A., and Quatrano, R.S. 2003. RNAi in the moss Physcomitrella patens. Plant
Physiology, 133: 470-474.
Bezanilla, M., Horton, A.C., Sevener H.M., and Quatrano, R.S. 2003. Phylogenetic Analysis
of New Plant Myosin Sequences. Journal of Molecular Evolution, 57: 229-239.
Lee, W.L., Bezanilla, M., and Pollard, T.D. 2000. Fission Yeast Myosin-I, Myo1p, Stimulates Actin
Assembly by Arp2/3 Complex and Shares Functions with WASp. Journal of Cell Biology, 151 (4): 789-799.
Bezanilla, M., Wilson, J., and Pollard, T.D. 2000. Myosin-II Isoforms in Fission Yeast Assemble
into the Contractile Rings at Distinct Times During Mitosis. Current Biology, 10 (7): 397-400.
Bezanilla, M., and Pollard, T.D. 2000. Myosin-II Tails Confer Unique Functions in S. pombe:
Characterization of a Novel Myosin-II Tail. Molecular Biology of the Cell, 11: 79-91.
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