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Continuing studies identified an
additional mutation that was similar to
ced-3 in preventing programmed cell H. Robert Horvitz death. However, this mutation was in a
different gene, which was located on a
different chromosome than ced-3. This
second gene was called ced-4. Similar
to mutations in ced-3, recessive mutations in ced-4 were found to block all
programmed cell deaths in the worm. The Impact
The isolation of C. elegans mutants by
Ellis and Horvitz provided the first identification of genes that were involved
in the process of programmed cell
death. The proteins encoded by the
ced-3 and ced-4 genes, as well as by (A) (B) Photomicrographs of a normal worm (A) and
a ced-3 mutant (B). Dying cells are highly refractile and are indicated by arrows in panel
A. These cells are not present in the mutant
animal. This material cannot be copied, reproduced, manufactured, or disseminated in any
form without express written permission from the publisher.
© 2009 Sinauer Associates, I...
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