S-phase patterns of cyclin (PCNA) antigen staining resemble topographical patterns of DNA synthesis. A role for cyclin in DNA replication?
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 [3H]thymidine 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
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Celis
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D000818:Animals; D001345:Autoradiography; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D004261:DNA Replication; D003850:Deoxyribonuclease I / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D007399:Interphase; D009698:Nucleoproteins / Q000502:physiology*; D018809:Proliferating Cell Nuclear Antigen; D013194:Staining and Labeling; D013936:Thymidine / Q000378:metabolism
D009698:Nucleoproteins; D018809:Proliferating Cell Nuclear Antigen; D003850:Deoxyribonuclease I; D013936:Thymidine