NF-Y recruitment of TFIID, multiple interactions with histone fold TAF(II)s.
The nuclear factor y (NF-Y) trimer and TFIID contain histone fold subunits, and their binding to the CCAAT and Initiator elements of the major histocompatibility complex class II Ea promoter is required for transcriptional activation. Using agarose-electrophoretic mobility shift assay we found that NF-Y increases the affinity of holo-TFIID for Ea in a CCAAT- and Inr-dependent manner. We began to dissect the interplay between NF-Y- and TBP-associated factors PO1II (TAF(II)s)-containing histone fold domains in protein-protein interactions and transfections. hTAF(II)20, hTAF(II)28, and hTAF(II)18-hTAF(II)28 bind to the NF-Y B-NF-YC histone fold dimer; hTAF(II)80 and hTAF(II)31-hTAF(II)80 interact with the trimer but not with the NF-YB-NF-YC dimer. The histone fold alpha2 helix of hTAF(II)80 is not required for NF-Y association, as determined by interactions with the naturally occurring splice variant hTAF(II)80 delta. Expression of hTAF(II)28 and hTAF(II)18 in mouse cells significantly and specifically reduced NF-Y activation in GAL4-based experiments, whereas hTAF(II)20 and hTAF(II)135 increased it. These results indicate that NF-Y (i) recruits purified holo-TFIID in vitro and (ii) can associate multiple TAF(II)s, potentially accommodating different core promoter architectures.
Frontini
Mattia
M
Dipartimento di Biologia Animale, Università di Modena e Reggio, Via Campi 213/d, Modena 41100, Italy.
Imbriano
Carol
C
diSilvio
Alberto
A
Bell
Brendan
B
Bogni
Alessia
A
Romier
Christophe
C
Moras
Dino
D
Tora
Laszlo
L
Davidson
Irwin
I
Mantovani
Roberto
R
D000818:Animals; D023081:CCAAT-Binding Factor / Q000378:metabolism*; D019281:Dimerization; D006657:Histones / Q000737:chemistry*; D051379:Mice; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017510:Protein Folding; D021122:Protein Subunits; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D035362:Transcription Factor TFIID; D019473:Transcription Factors, TFII / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D014162:Transfection
D023081:CCAAT-Binding Factor; D006657:Histones; D021122:Protein Subunits; D011994:Recombinant Proteins; D035362:Transcription Factor TFIID; D019473:Transcription Factors, TFII