Recently, i always got high background low signal norther blot. The signal was very easy to washed away (10 min washing at 60 degree) The protocol was same as i used before. But i had no problem of the northern blot before.
The diffences were
1) i made the probe again because the old one was used up.
2) i bought new membrane with same catalog number but different lot number
At first i though it might be the probe problem. But i checked the probe on agarose gel. The size and concentration were right. No degradation was seen from the gel.
When i used GAPDH to do the northen blot, it gave me very good result.
Can anybody here tell me the possible reasons?
Thanks a lot