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Screens for Mutations that Specifically Disrupt Syncytial Divisions
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Drosophila is one of the few organisms in which genetic analysis of the events immediately following fertilization is feasible.
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To understand the molecular and cellular events guiding initial nuclear
divisions of the Drosophila embryo, our laboratory carries out
screens for mutations that specifically disrupt syncytial divisions. The first
2 to 3 hours of development are primarily controlled by products supplied
to the embryo during oogenesis. Our efforts, therefore, focus on isolating
maternal-effect mutations. We
employ three genetic strategies in our research: strict maternal-effect
mutations, germ-line clonal analysis, and temperature-sensitive lethals.
We are particularly interested in the class of mutations that
disrupt divisions only after the nuclei reach the cortex. During the cortical
cycles, centrosomal mediated rearrangements in the actin cytoskeleton are
required for proper nuclear divisions. Therefore, many of the mutations
that specifically disrupt the cortical divisions are likely to identify key
genes required for these cortical rearrangements. To date, we and other
labs have isolated and cloned 12 of these mutations. These fall into three
major classes: centrosomal proteins, cortical cytoskeletal components, and
cell cycle regulators (see Summary Table
for detail). This work has yielded valuable insights into the
mechanisms that coordinate nuclear and cytoplasmic events, as well as the
mechanisms by which the centrosome mediates cytoskeletal dynamics (see
pages on the centrosome, cytokinesis, and checkpoints for more detail).
Sullivan, W., J. Miden, and B. Alberts. (1990) daughterless
abo-like (dal),
a Drosophila maternal-effect mutation that exhibits abnormal centrosome
separation during the late blastoderm divisions.
Development 110: 311-323.
Sullivan, W., P. Fogarty,and W. Theurkauf. (1993) Mutations
affecting the cytoskeletal organization of syncytial Drosophila embryos. Development 118:1245-1254.
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