• 한국발생생물학회지:발생과생식
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• 제5권2호
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• pp.131-136
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• 2001

초파리 발생과정에서 세포사멸에 관여하는 유전자인 reaper(rpr), grim, dcp-1, diap1, diap1, diap2의 발현양상을 경제적 RT-PCR 방법으로 분석하였다. 세포사멸 유도 유전자인 rpr, grim의 발현양상은 발생단계에 따른 ecdysone titer 변화 양상과 매우 유사하였다. Effector caspase인 dcp-1 전사체는 초기 배와 암컷 성체에서 높은 발현을 보였다. 반면에 세포사멸 억제인자인 diap1과 diap2 전사체는 세포사멸 유도 인자인 rpr과 girm 전사체와 서로 상반적인 양상으로 발현되었다. 또한, 유주 3령 유충의 발생단계 별로 침샘조직과 성체원기조직에서 rpr, diap2, dcp-1의 전사체의 양적 변동을 분석하였다. rpr, diap2의 전사체양은 두 조직에서 서로 상반적으로 변화하였다. 이 결과는 정상 발생과정에서 세포죽음 관련유전자들의 발현이 ecdysone 신호에 의해 조절됨을 암시해 주었다.

• Molecules and Cells
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• 제20권3호
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• pp.446-451
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• 2005

Diap1 is an essential Drosophila cell death regulator that binds to caspases and inhibits their activity. Reaper, Grim and Hid each antagonize Diap1 by binding to its BIR domain, activating the caspases and eventually causing cell death. Reaper and Hid induce cell death in a Ring-dependent manner by stimulating Diap1 auto-ubiquitination and degradation. It was not clear that how Grim causes the ubiquitination and degradation of Diap1 in Grim-dependent cell death. We found that Grim stimulates poly-ubiquitination of Diap1 in the presence of UbcD1 and that it binds to UbcD1 in a GST pull-down assay, so presumably promoting Diap1 degradation. The possibility that dBruce is another E2 interacting with Diap1 was examined. The UBC domain of dBruce slightly stimulated poly-ubiquitination of Diap1 in Drosophila extracts but not in the reconstitution assay. However Grim did not stimulate Diap1 poly-ubiquitination in the presence of the UBC domain of dBruce. Taken together, these results suggest that Grim stimulates the poly-ubiquitination and presumably degradation of Diap1 in a novel way by binding to UbcD1 but not to the UBC domain of dBruce as an E2.

• Molecules and Cells
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• 제24권3호
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• pp.445-451
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• 2007

Translation initiation factor 4E (eIF4E) is a key regulator of protein synthesis. Abnormal regulation of eIF4E is closely linked to oncogenic transformation. Several regulatory mechanisms affecting eIF4E are discussed, including transcriptional regulation, phosphorylation and binding of an inhibitor protein. However it is not clear how the level of eIF4E protein is regulated under basal conditions. Here we demonstrate that Diap1 (Drosophila Inhibitor of Apoptosis Protein), a cell death inhibitor, binds directly to eIF4E and poly-ubiquitinates it via its E3 ligase activity, promoting its proteasome-dependent degradation. Expression of Diap1 caused a reduction of Cyclin D1 protein level and inhibited the growth stimulation induced by overexpression of eIF4E. Taken together, our results suggest that the level of eIF4E protein is regulated by Diap1, and that IAPs may play a role in cap-dependent translation by regulating the level of eIF4E protein.