Anti-Flag M2 crossactivates with mouse tissue? - (Nov/16/2004 )

hello all

I made a transgenic mouse. the inserted protein is fused with a Flag tag on C-terminues. when I took the tissues from trans/+ mouse and wild type +/+. I found that the anti-Flag M2 (sigma) cross-reactivated with the wild type tissue ( western Blot). And it was so strange that the nonspecific band is the same MW as my inserted protein. I am sure that the wild type mouse has no Flag at all.
Does anyone have the same exprience?
Now I am thinking to change a rabbit-derived anti-Flag antibody. I checked some catalog books and I found that most polyclonal is suitable for western blot but not for immunohistochemistry. I also want to apply the immunostaining study. Does anyone have a good suggestion?

Hello, I know you have written this post long time ago, but let me try.

Do you found any solution ? I am having a similar problem. My negative control shows a nonspecific band with the same MW of my target protein. What can I do ? I am completely lost.

Thanks a lot,
Tati