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TdIF2 is a nucleolar protein that promotes rRNA gene promoter activity
Author(s) -
Koiwai Kotaro,
Noma Satoshi,
Takahashi Yasuhiro,
Hayano Takahide,
Maezawa So,
Kouda Kousuke,
Matsumoto Takuro,
Suzuki Masahiro,
Furuichi Masaki,
Koiwai Osamu
Publication year - 2011
Publication title -
genes to cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.912
H-Index - 115
eISSN - 1365-2443
pISSN - 1356-9597
DOI - 10.1111/j.1365-2443.2011.01524.x
Subject(s) - biology , nucleolus , microbiology and biotechnology , chromatin immunoprecipitation , histone acetyltransferase , histone , immunoprecipitation , ribosomal protein , acetylation , chromatin , nuclear protein , gene , promoter , biochemistry , rna , transcription factor , ribosome , gene expression , nucleus
Terminal deoxynucleotidyltransferase (TdT) interacting factor 2 (TdIF2) is an acidic protein that binds to TdT. TdIF2 binds to DNA and core histones and contains an acidic‐amino acid‐rich region in its C‐terminus. It has therefore been suggested to function as a histone chaperone within the nucleus. TdIF2 localized within the nucleolus in HEK 293T cells, and its N‐terminal (residues 1–234) and C‐terminal (residues 606–756) regions were crucial for the nucleolar localization. A chromatin immunoprecipitation (ChIP) assay showed that TdIF2 associated with the promoter of human ribosomal RNA genes (hrDNAP), and an in vitro luciferase assay system showed that it promoted hrDNAP activity. Using the yeast two‐hybrid system with TdIF2 as the bait, we isolated the cDNA encoding HIV Tat interactive protein 60 (Tip60), which has histone acetyltransferase (HAT) activity, as a TdIF2‐binding protein. TdIF2 bound to Tip60 in vitro and in vivo , inhibited the Tip60 HAT activity in vitro and co‐localized with Tip60 within the nucleolus. In addition, TdIF2 promotes upstream binding factor (UBF) acetylation in vivo . Thus, TdIF2 might promote hrDNAP activity by suppressing Tip60’s HAT activity and promoting UBF acetylation.