The research in Dr. Yanofsky's lab focuses on the molecular mechanisms which control the initiation and development of flowers and fruits in higher plants, with particular emphasis on the model system of Arabidopsis. Our recent studies of flower development have uncovered important new regulators of flower organ identity, including the three SEPALLATA MADS-box genes that act redundantly to specify the identity of petals, stamens and carpels. Our current efforts are focused on studying the interactions between the SEPALLATA genes with other organ identity genes and on identifying their direct downstream targets. The past decade has revealed
rapid progress toward identifying the major genes controlling
flower organ identity and formation of the different parts of
the fruit. However, almost nothing is currently known about the
differentiation of specific cell types within organs. Our future
research will focus on identifying the cascade of gene activity
that ultimately leads to differentiation of individual cell types
within organs. Roeder, A.H.K., Ferrándiz, C., and Yanofsky, M.F. (2003). The role of the REPLUMLESS homeodomain protein in patterning the Arabidopsis fruit. Current Biology, 13:630-635. Pinyopich, A., Ditta, G.S., Savidge, B., Liljegren, S.J., Baumann, E., Wisman, E., and Yanofsky, M.F. (2003). Unraveling the redundant roles of MADS-box genes during carpel and ovule development. Nature 424: 85-88. Liljegren, S.J., Roeder, A.H.K., Kempin, S.A., Gremski, K, Østergaard, L., Guimil, S., Khammungkhune, D. and Yanofsky, M.F. (2004). Control of fruit patterning in Arabidopsis by INDEHISCENT. Cell 116:843-853. Dinneny, J. R., Weigel, D., and Yanofsky, M.F. (2005). A genetic framework for fruit patterning in Arabidopsis thaliana. Development 132:4687-4696. Marty Yanofsky received his Ph.D. from the University of Washington and was an NSF Postdoctoral Fellow in Plant Biology at Caltech. He was the recipient of a Packard Fellowship for Science and Engineering and a Beckman Young Investigator Award. |
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Much
of our recent research has focused on fruit development, which
is arguably the most complex plant organ. Arabidopsis fruit, which
are derived from the fertilized gynoecium (carpels), consist of
a number of distinct tissue types, including the valves, replum
and dehiscence zone. The dehiscence zone consists of a narrow
band of cells that extends along the entire length of the fruit.
Upon fruit maturation, cell separation within the dehiscence zone
allows the valves to detach from the replum and for the seeds
to be dispersed. We have shown that the SHATTERPROOF1 (SHP1)
and SHP2 MADS-box genes act redundantly to specify dehiscence
zone cell fate. The SHP genes act to promote the expression
of the INDEHISCENT bHLH gene, which is also required for
dehiscence zone differentiation. Because the dehiscence zone fails
to differentiate in these mutants, the fruits fail to open and
the seeds cannot be dispersed through their normal mechanism.
We have also shown that the FRUITFULL MADS-box gene is
required for the post-fertilization elongation of the fruit and
is required for valve cell differentiation. Interestingly, the
FRUITFULL gene product negatively regulates the SHP
and IND genes such that the SHP and IND genes
are ectopically expressed in fruitfull mutant valves. More
recently, we have shown that the REPLUMLESS gene is required
for formation of the replum. These studies have allowed us to
begin to build a framework for the regulatory interactions that
underlie fruit development in Arabidopsis. 
