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Old 03-10-2017, 11:02 AM   #1
anjama
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Location: Florida

Join Date: Mar 2016
Posts: 15
Default PstI methylation sensitivity

So my lab is in the process of understanding and implementing a protocol for several species. One point of confusion we are trying to figure out is whether or not the PstI restriction enzyme is methylation sensitive. The reason this is a concern is that the protocol calls for methylation sensitive enzymes, and people involved in developing the protocol use PstI as a methylation-sensitive enzyme for a variety of species ranging from plants to mammals. However, the product pages for Fisher and NEB both list PstI as not sensitive for dam, dcm, and CpG sites. The only indication I can see on manufacturer sites that it is sensitive is a reference chart on Promega's website that lists it as sensitive to CpNpG methylation sites.

Just taking a quick look through primary literature, many papers seem to refer to PstI as methylation sensitive, but I've also seen some that refer to it as non-sensitive. From what I gather, CpNpG sites are predominately a plant thing, whereas the mammal genome consists of primarily CpG sites (I think I saw the number 97% somewhere), which seems like it explains the discrepancy between different papers. Is this right? Is it correct to consider PstI non-methylation sensitive for mammals, but methylation sensitive for plants? Or am I missing something? Thanks
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