The peripheral lamina of eukaryotic nuclei is composed of polypeptides called 
lamins that vary in number from one to four according to organism, cell type, 
and differentiated state of the cells. Early embryonic cells and stem cells of 
mammals generally possess only lamin B while lamins A and C appear later during 
differentiation. To study the role of the late appearance of lamins A and C in 
the differentiated phenotype, we have performed transfection of cDNAs coding for 
human lamins A or C into mouse embryonal carcinoma (EC) cell lines F9 and P19 
lacking these two lamins. Transient transfections have shown that lamins A or C 
could be expressed, translocated to the peripheral lamina, and distributed into 
daughter cell nuclei after mitosis. These results demonstrated that EC cells 
devoid of lamins A and C nevertheless possessed the appropriate mechanisms for 
the localization and mitotic redistribution of exogenous lamins A and C.