Antibiotics as Selection Agents

Blog entry

We all know why pen-strep is in our cultures. But when you landed your first lab gig as a student, did you really know why your PI had upwards of 15 antibiotics in the freezer? I didn’t.  True, most of us are pretty familiar with the use of antibiotics as selection agents, but some people still ask how it works.  Well, fasten your seatbelt! I’m fixin’ to shed some knowledge and it’s coming your way! No Holiday Inn Express needed!

Not all antibiotics spare eukaryotic cells and those are the ones we typically use as selection agents. In a nutshell, you take a gene you want to put into your cells, and you piggy-back that gene with another gene that makes the cell it gets into resistant to a particular antibiotic. Then, you put those genes into your cultures and hope they wiggle into your cells and insert themselves into a favorable part of the cells’ genomes (with a little help from some reagents and/or electricity). Remember, one of those genes should render the cells that have it resistant to a specific antibiotic (let’s say neomycin).  Then, you  put neomycin  into the culture and …Voila! You have just created a culture of cells that express the gene you want them to express. Why? Because the ones that took up the genes survived the antibiotic onslaught while the ones that didn’t were hurled into oblivion. 

I checked out Gemini’s website and they have something like 18 different antibiotic products available. They’re always happy to send samples and they’d be happy to help you out. Tell them I sent you (I always wanted to say that).