Sumoylation of HIF-1a in Experimental Brain Death Figure 4. Preferential augmentation of HIF-1a transcription activity in RVLM during the pro-life phase. (A and B) Illustrative gels depicting HIF-1 DNA binding in nuclear extracts from ventrolateral medulla of sham or aCSF controls, or during Mev intoxication. Results from supershift analysis illustrated in (B) were obtained from nuclear extracts from ventrolateral medulla collected during Phase I that was preincubated with antiserum against HIF-1a or HIF-1b. Competitive assay using unlabeled HIF oligonucleotide served as the negative control (Cold). These results are typical of 4 animals from each experimental group. (C and D) Illustrative gels or summary of fold changes against sham (S) controls of HIF-1a or HIF-2a from proteins immunoprecipitated by anti-HIF-1b antiserum in the nuclear (C) or cytosolic (D) fraction of samples collected from ventrolateral medulla of sham (S) or aCSF (V) controls or during Phases MI and MII Mev intoxication. Values are mean 6 SEM of triplicate analyses on samples pooled from 4–6 animals in each group. *P,0.05 versus aCSF group in the post hoc Scheff e´ multiple-range test. doi:10.1371/journal.pone.0017375.g004 PLoS ONE | www.plosone.org 8 March 2011 | Volume 6 | Issue 3 | e17375