TAF9b (formerly TAF9L) is a bona fide TAF that has unique and overlapping roles with TAF9.
TFIID plays a key role in transcription initiation of RNA polymerase II preinitiation complex assembly. TFIID is comprised of the TATA box binding protein (TBP) and 14 TBP-associated factors (TAFs). A second set of transcriptional regulatory multiprotein complexes containing TAFs has been described (called SAGA, TFTC, STAGA, and PCAF/GCN5). Using matrix-assisted laser desorption ionization mass spectrometry, we identified a novel TFTC subunit, human TAF9Like, encoded by a TAF9 paralogue gene. We show that TAF9Like is a subunit of TFIID, and thus, it will be called TAF9b. TFIID and TFTC complexes in which both TAF9 and TAF9b are present exist. In vitro and in vivo experiments indicate that the interactions between TAF9b and TAF6 or TAF9 and TAF6 histone fold pairs are similar. We observed a differential induction of TAF9 and TAF9b during apoptosis that, together with their different ability to stabilize p53, points to distinct requirements for the two proteins in gene regulation. Small interfering RNA (siRNA) knockdown of TAF9 and TAF9b revealed that both genes are essential for cell viability. Gene expression analysis of cells treated with either TAF9 or TAF9b siRNAs indicates that the two proteins regulate different sets of genes with only a small overlap. Taken together, these data demonstrate that TAF9 and TAF9b share some of their functions, but more importantly, they have distinct roles in the transcriptional regulatory process.
Frontini
Mattia
M
Department of Transcription, Institut de Génétique et de Biologie Moléculaire et Cellulaire, UMR 7104, BP 10142, 67404 Illkirch Cedex, CU de Strasbourg, France.
Soutoglou
Evi
E
Argentini
Manuela
M
Bole-Feysot
Christine
C
Jost
Bernard
B
Scheer
Elisabeth
E
Tora
Làszlò
L
D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis; D002460:Cell Line; D002470:Cell Survival / Q000235:genetics / Q000502:physiology; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000502:physiology*; D006801:Humans; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis; D021122:Protein Subunits / Q000032:analysis / Q000235:genetics / Q000502:physiology; D034741:RNA, Small Interfering / Q000235:genetics / Q000494:pharmacology; D051381:Rats; D035381:TATA-Binding Protein Associated Factors / Q000032:analysis / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D035362:Transcription Factor TFIID / Q000032:analysis / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D015533:Transcriptional Activation; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
D021122:Protein Subunits; D034741:RNA, Small Interfering; C106849:TAF9 protein, human; C502209:TAF9b protein, human; D035381:TATA-Binding Protein Associated Factors; D035362:Transcription Factor TFIID; D016159:Tumor Suppressor Protein p53