The chromatin of differentiating erythroblasts is cleaved into large size fragments independent of caspase activated DNase and apoptosis inducing factor.
Erythroblast cell differentiation involves self-controlled and limited nuclear proteolysis prior nucleus loss. Early evidence suggests that apoptotic-like pathways are activated during this process. The chromatin of developing erythroblasts becomes fragmented in vivo, however, the exact mechanisms and molecules involved remain elusive. In this study, erythroblasts were differentiated in culture from CD34-enriched umbilical cord blood progenitor cells and the characteristics of DNA fragmentation were examined. This analysis shows that the chromatin of differentiating erythroblasts is cleaved into discrete fragments of 50-200 kb. This process most likely involves one or several endonucleases as we detect in vivo double strand DNA cleavage. However, major players of the apoptotic DNA degradation, caspase activated DNase and apoptosis inducing factor, are not activated in these cells. Therefore, our data suggests that erythroblast chromatin degradation may involve enzymes distinct form those active in apoptotic cells.
Hristoskova
Sashka
S
Laboratory for Prenatal Medicine, University Women's Hospital/Department of Research, University of Basel, Basel, Switzerland.
Holzgreve
Wolfgang
W
Hahn
Sinuhe
S
Rusterholz
Corinne
C
D017209:Apoptosis / Q000502:physiology; D051033:Apoptosis Inducing Factor / Q000378:metabolism*; D020169:Caspases / Q000378:metabolism*; D048430:Cell Shape; D002478:Cells, Cultured; D002843:Chromatin / Q000378:metabolism*; D053938:DNA Fragmentation; D003851:Deoxyribonucleases / Q000378:metabolism*; D004789:Enzyme Activation; D004900:Erythroblasts / Q000166:cytology / Q000502:physiology*; D006801:Humans; D020287:In Situ Nick-End Labeling
D051033:Apoptosis Inducing Factor; D002843:Chromatin; D003851:Deoxyribonucleases; C109663:caspase-activated deoxyribonuclease; D020169:Caspases