Key points are not available for this paper at this time.
The sequence of cyclin (proliferating cell nuclear antigen, PCNA), antigen staining throughout the cell cycle of African green monkey kidney cells (BS-C-1) has been determined by indirect immunofluorescence using PCNA autoantibodies specific for this protein. Patterns of cyclin staining observed between the beginning of S-phase and maximum DNA synthesis are similar to those reported in human AMA cells (1985) Proc. Natl. Acad. Sci. USA 82, 3262-3266, while those detected thereafter are significantly different; the most striking feature being the continuous staining of the nucleoli up to or very near the S/G2 border of the cell cycle. Using 3Hthymidine autoradiography and indirect immunofluorescence of the same cells we show a remarkable correlation between cyclin antigen distribution and topographical patterns of DNA synthesis. In addition, we present evidence showing that DNase I treatment of Triton-extracted monolayers abolishes cyclin antigen staining but does not result in a substantial release of this protein. Taken together the above observations argue for a role of cyclin in some aspect of DNA replication.
Madsen et al. (Mon,) studied this question.