Research Paper Volume 4, Issue 10 pp 674—685

Figure 5. Decreased binding of PARP-1 to GST-NEIL1 with mouse age. (A) Liver nuclear extracts were made from 3 different young (7 month) and 3 different old (17 month) mice and used for GST-precipitations with the indicated fusion proteins. Precipitations were probed with anti-PARP-1 and anti-PAR antibodies and stained with Ponceau S to visualize the fusion proteins. The relative amount of PARP-1 binding and PAR levels in precipitations were quantified from immunoblots and normalized to the amount of GST-fusion protein. The numbers below the blots represent the relative level of PARP-1 binding and the histograms in (B) represent the average PARP-1 binding and PAR levels in precipitations from the 3 young and 3 old mice. *P<0.05 comparing young and old mice using Student's t-test. Similar results were obtained in another independent experiment. (C) Liver nuclear extracts from young and old mice were probed by immunoblotting with anti-PARP-1 and anti-NEIL1 antibodies and reprobed with anti-TBP antibodies as a protein loading control. The numbers below the blots represent the level of PARP-1 or NEIL1 normalized to TBP. The histogram in (D) represents the average levels of NEIL1 and PARP-1 + SEM from the 3 young and 3 old mice.