FIG. 1.

Identification of TAF9b as a component of TFTC by mass spectrometry. (A) TAF9- and TAF9b-specific peptide masses (measured and computed) obtained by MALDI-TOF analysis and their sequences are represented. The accuracy between the measured and computed masses is shown in parts per million (ppm). M-ox, oxidized methionine. (B) Protein sequence comparison between human TAF9 and TAF9b (formerly TAF9L). The amino acid one-letter code is used. Identical amino acids are shown by bars, and double points represent residues with the same physicochemical properties. The peptides used for generating TAF9- or TAF9b (formerly TAF9L)-specific antibodies are boxed. (C) Recombinant TAF9 (rTAF9) (lanes 2 and 4) and TAF9b (rTAF9b) (formerly TAF9L) (lanes 1 and 3) were overexpressed using the baculovirus system in Sf9 cells, cells were lysed, and proteins were separated by SDS-PAGE and tested by Western blot using the antibodies raised against either TAF9 (α-TAF9) (lanes 1 and 2) or TAF9b (α-TAF9b) (lanes 3 and 4), respectively. (D) HeLa cell NE was prepared in the presence of phosphatase inhibitors, and increasing amounts (15, 30, and 60 μg) were separated by SDS-PAGE and tested by Western blot using the antibodies raised against either TAF9 (lanes 1, 2, and 3) or TAF9b (lanes 4, 5, and 6), respectively.