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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 2007

Michael O. Hengartner and H. Robert Horvitz; Activation of C. elegans cell death protein CED-9 by an amino-acid substitution in a domain conserved in Bcl-2. Nature 369:318-320, 1994

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The Caenorhabditis elegans gene ced-9 and the human protooncogene bcl-2, both of which protect cells from programmed cell death, are members of the same gene family. ced-9 and bcl-2 were discovered because of the effects of dominant gain-of-function mutations. Such bcl-2 mutations, which are commonly found in follicular lymphoma, are translocations that result in over-expression of a normal Bcl-2 protein in B cells. Here we report that, by contrast, the ced-9 (n1950) gain-of-function mutation affects the open reading frame of ced-9 and results in a glycine-to-glutamate substitution in a region highly conserved among all ced-9/bcl-2 family members. We conclude that this glycine has an important function in ced-9 regulation, and we suggest that alteration of this glycine in other members of the ced-9/bcl-2 family might lead to oncogenic activation. We also present genetic evidence suggesting that the CED-9 protein might exist in two distinct forms that have opposite effects on cell death.