which protein can I use as a loading control for nuclear protein fraction? - (Mar/19/2012 )

which protein can I use as a loading control for nuclear protein fraction?
I have run several times and I have used Beta-Actin as control for nuclear protein fraction. but I have fluctuation between bands even after normalization by Biorad-Protein Assay.

How about some histone proteins? There are some good Histone H3 antibodies. Also, you might consider Lamin A/C.

We frequently use TATA binding protein for nuclear extracts as loading control. You can also check if you have cytosolic contamination in your nuclear fraction by probing for A/B tubulin, as tubulin should not be present in the nucleus.