The contribution of apoptosis-inducing factor, caspase-activated DNase, and inhibitor of caspase-activated DNase to the nuclear phenotype and DNA degradation during apoptosis.
We have assessed the contribution of apoptosis-inducing factor (AIF) and inhibitor of caspase-activated DNase (ICAD) to the nuclear morphology and DNA degradation pattern in staurosporine-induced apoptosis. Expression of D117E ICAD, a mutant that is resistant to caspase cleavage at residue 117, prevented low molecular weight (LMW) DNA fragmentation, stage II nuclear morphology, and detection of terminal deoxynucleotidyl transferase staining. However, high molecular weight (HMW) DNA fragmentation and stage I nuclear morphology remained unaffected. On the other hand, expression of either D224E or wild type ICAD had no effect on DNA fragmentation or nuclear morphology. In addition, both HMW and LMW DNA degradation required functional executor caspases. Interestingly, silencing of endogenous AIF abolished type I nuclear morphology without any effect on HMW or LMW DNA fragmentation. Together, these results demonstrate that AIF is responsible for stage I nuclear morphology and suggest that HMW DNA degradation is a caspase-activated DNase and AIF-independent process.
Yuste
Victor J
VJ
Department of Ciències Mèdiques Bàsiques, Cell Signalling and Apoptosis Group, Facultat de Medicina, Universitat de Lleida, Montserrat Roig, 2, E-25008 Lleida, Spain.
Sánchez-López
Isabel
I
Solé
Carme
C
Moubarak
Rana S
RS
Bayascas
José R
JR
Dolcet
Xavier
X
Encinas
Mario
M
Susin
Santos A
SA
Comella
Joan X
JX
D017209:Apoptosis; D051033:Apoptosis Inducing Factor / Q000502:physiology*; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism*; D004247:DNA / Q000737:chemistry*; D053938:DNA Fragmentation; D003851:Deoxyribonucleases / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D020287:In Situ Nick-End Labeling; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D008970:Molecular Weight; D016296:Mutagenesis; D010641:Phenotype; D010957:Plasmids / Q000378:metabolism; D019311:Staurosporine / Q000494:pharmacology; D014162:Transfection
D051033:Apoptosis Inducing Factor; D004791:Enzyme Inhibitors; D004247:DNA; D003851:Deoxyribonucleases; C109663:caspase-activated deoxyribonuclease; D019311:Staurosporine