A comparison of methods for the extraction of nucleoprotein complexes from SV40-infected cells

A comparison was made between two alternative methods for the nuclear extraction of Simian virus 40 (SV40) virions and nucleoprotein complexes (NPCs) from SV40-infected TC7 cells. The low-salt hypotonic method of Su and DePamphilis (1976) was compared with the detergent method of Garber et al. (1978), since other methods had been shown to result in virion breakdown. There was no disruption of mature SV40 virions with either of these extraction procedures. There was, however, considerably more effective extraction of SV40 NPCs, known to contain large tumor (T) antigen, using the low-salt hypotonic method as opposed to the detergent method. Thus, the low-salt hypotonic method for extraction should be the method of choice when studying SV40 DNA replication or the function of SV40 T antigen in SV40 nucleoprotein complexes.