【摘要】 <正> 前言大多数真核细胞处于间期时看不到核内有染色体结构,但细胞进入分裂期时核内染色质逐渐聚集形成染色体。Rao 和Johnson 对染色体的周期性变化(聚集更多还原

【Abstract】 Prematurely condensed chromoso-mes in interphase nuclei of the hepa-toma cells has been successfully indu-ced by cell fusion with mitotic and in-terphase hepatoma cells.Cell fusionwas mediated by New Castle DiseaseVirus （NDV） or polyethylene glycol（PEG）.The mitotic cell populationwas obtained by shaking off from cellstreated with excess thymidine block orcolchicine （0.012 μg/ml） for 20-24 hrs.After the completion of cell fusion insuspension,the maximal frequency ofPCC induction was reached in 15-30minutes.The increase of NDV con-centration by 10 fold raised the fre-quency of PCC induction from 14.3%to 24.7%.A three fold increase in theratio of mitotic to interphase cells raisedthe frequency of PCC induction from18.6% to 43.4%.The maximal fre-quency of PCC induction by cell fusion（M/I 1∶1） with PEG was 25.3—39%,higher than that reported by Lau etal.The morphology of the prematur-ely condensed chromosomes is characte-ristic for the different stage of the cellcycle,viz,sigle long chromatid for G₁,double long chromatid for G₂,and“pulverized”chromosome region for S.更多还原