Figure 1
From: Ribosomal transcription is regulated by PGC-1alpha and disturbed in Huntington’s disease
Localization of PGC-1α in the nucleoli and association with the unmethylated rDNA. (1a) PGC-1α is condensed located in the nucleolus as shown by the merge with nucleolin (staining of the nucleoli). Confocal microscopy of untreated HEK cells kept under 21% pO2. N = 155 nucleoli of HEK cells were investigated for statistical analysis (Figure S2). (1b) PGC-1α associates with the rDNA-promotor (Prom), gene internal sequences (H4, H8) and the intergenic spacer (IGS, H23/27). QPCR of ChIP assay with HEK cells and PGC-1α antibody (Calbiochem). Samples were normalized to input (native chromatin as positive control). N = 3; one way ANOVA; column: mean ± SD. Control experiments using bona fide PGC-1α targets like LMNA (lamin A), PCK1 (phosphoenolpyruvate carboxykinase 1) and IRS1 (insulin receptor substance-1) show a clear association of PGC-1α with these genes. qPCR of ChIP experiments, n = 3, column: mean ± SD. (1c) PGC-1α associates with the unmethylated, active rDNA-promotor. ChIP assay with HEK cells kept under 21% pO2, transfected with flag-tagged PGC-1α. Digest with methylation-sensitive enzymes Hpa II (digests only unmethylated sequences) and Msp I (digests both methylated and unmethylated sequences). qPCR with HrChIP-primer. Pol I and PGC-1α were normalized to the undigested chromatin. ****p < 0.0001; one way ANOVA; N = 6; column: mean ± SD.
