Human eythroblasts were cultured from mononuclear cells from cord blood or venous blood of a patient with congenital dyserythropoietic anemia. type III (CDA III). They were cultured in hypoxic condition according to the method of Wada et. al., modified by us. Two polypeptides involved in cell mitosis : alpha-tubulin and proliferating cell nuclear antigen (PCNA), were studied by fluorescent mononuclear antibody method.
1. alpha-tubulin : In CDA III erythroblasts, plentry of alpha-tubulin-rich cell prosesses, which were spike-shape or rodlike, were found, while in normal erythroblasts, number of such cell processes were These cell processes may be reflecting the vigorous process-forming activity of CDA III erythroblasts observed by us in the previous study using long-term time-lapse cinemicrography of them. Some of these processes might possibly be remnants of the post-mitotic intercellular bridges. In multinuclear or segment-nuclear CDA III erythroblasts, no apparent abnormalities of alpha-tubulin was observed.
2. Proliferating cell nuclear antigen : The amount of PCNA in erythroblasts was measured simultaneously with DNA by FACS, using fluorescent mononuclear antibody and propidium iodide. The amount of PCNA of normal erythroblasts increased gradually during S-phase and reached maximum at G_2-phase. The amount of PCNA of CDA III erythroblasts showed similar increase during S-phase. In small number of CDA III erythroblasts with DNA more than 4C, the amount of PCNA tended to be large paralleling to their amount of DNA.Further studies will be needed to analyze the significance of this finding.