[Investigation of nuclear lamina in Tetrahymena thermophila]

The nuclear lamina in the nuclei of Tetrahymena thermophila was investigated using the techniques of selective extraction and embedment-free electron microscopy, as well as immunofluorescence staining. By means of immunoblotting and protein isolating, the lamina was found to consist mainly of a 66 KD polypeptide. While rabbit-anti-lamins polyclonal antibodies crossreacted with this protein, neither murine-anti-lamin A&C mAB C23 nor murine-anti-lamin III mAB 223 showed positive reaction with it. It was also demonstrated that the lamin is not so rich as that in mammalian cells. The existence of lamina in T. thermophila, a unicellular organism, seems to show that the lamina is a basic characteristic structure of eukaryotic cells, and that the function of the lamina may not be limited to the process of breakdown and reconstitution of nuclear envelope during mitosis.