Question about Southern blotting - (Jun/09/2006 )

Hello everyone,

I want to do a southern blotting. But after the blotting I wish to freeze my membranes and do the hybridization assay later. I am using positively charged nylon membranes and will do alkaline transer. I do not know at which part of the process I can halt and freeze the membranes. To be precise, it is about blocking. Can do blocking later or not?

Thanks a lot,
Zaanaa

Hi. After you've done the alkaline transfer of DNA onto nylon membrane, you can UV cross-link it and keep it wrapped with saranwrap. Then store the blot in 4C fridge.

Since you're using positively charged nylon membrane, you can opt not to UV-crosslink (but I prefer it anyway). I normally keep the DNA blot refrigerated this way for > 1 months without problem.

What if I want to take the membrane to another lab (say another country!!) that would take a couple of days. Should I put the membrane on dry ice or a flask with ice would suffice? By the way, is blocking necessary before storing the membrane or can I do it later?

Thanks again!

I think it'd be suffice just to keep the blot dry at room temperature for a couple of days when you deliver the blot to other country. No need dry ice, just ensure that the blot is wrapped with saran wrap and kept away from moisture. I don't think you should block the membrane.