Posted 11 May 2009 - 01:21 AM
Posted 15 May 2009 - 10:56 PM
2nd, EcoRI is impaired by CpG methylation, make sure the strain you use to express the plasmid has no methylation
3rd, it could be your EcoRI in the freezer was too old and expired (this happened in my lab). You can use a control plasmid, eg pUC and try to cut it (this make sure your enzyme is working).
Posted 16 May 2009 - 12:19 AM
Can u tell us more about the condition you do ur digestion . the gel need to be run longer and well wether or not it actually have a restriction site for that EcoRI. more info on ur plasmid would be desirable