This protocol has been designed to measure the in-vitro DNA polymerization activity in crude cell extracts of the Antarctic bacterium Pseudomonas syrinagae Lz4W. This bacterium can grow at 4 °C with optimum growth rate at 22 °C. The slow growth rate of the bacterium observed at low temperature (4 °C) compared to higher temperature (22 °C) can be attributed to the reduced rate of DNA replication at low temperature. Here we describe a protocol which we have used to quantify the in vitro DNA polymerization of cell extracts at two different temperatures.
Pseudomonas syringae (P. syringae) Lz4W strain (Shivaji et al., 1989)
Escherichia coli (E. coli) DH5alpha strain
Random primer labelling kit (JONAKI Laboratory, catalog number: LCK 2 ) Note: Many companies like Roche Diagnostics, Thermo Fisher Scientific, Agilent, Clontech etc. provide similar kit.
Sinha, A. K. and Ray, M. K. (2014). In vitro DNA Polymerization Activity Assay Using Cell-free Extracts. Bio-protocol 4(16): e1207. DOI: 10.21769/BioProtoc.1207.