1: J Biol Chem. 2003 May 16;278(20):18649-57. Epub 2003 Mar 5. 

The small nuclear RNA-activating protein 190 Myb DNA binding domain stimulates
TATA box-binding protein-TATA box recognition.

Hinkley CS, Hirsch HA, Gu L, LaMere B, Henry RW.

Department of Biochemistry and Molecular Biology, Michigan State University,
East Lansing, Michigan 48824, USA.

Human U6 small nuclear RNA (snRNA) gene transcription by RNA polymerase III
requires cooperative promoter binding involving the snRNA-activating protein
complex (SNAP(c)) and the TATA-box binding protein (TBP). To investigate the
role of SNAP(c) for TBP function at U6 promoters, TBP recruitment assays were
performed using full-length TBP and a mini-SNAP(c) containing SNAP43, SNAP50,
and a truncated SNAP190. Mini-SNAP(c) efficiently recruits TBP to the U6 TATA
box, and two SNAP(c) subunits, SNAP43 and SNAP190, directly interact with the
TBP DNA binding domain. Truncated SNAP190 containing only the Myb DNA binding
domain is sufficient for TBP recruitment to the TATA box. Therefore, the SNAP190
Myb domain functions both to specifically recognize the proximal sequence
element present in the core promoters of human snRNA genes and to stimulate TBP
recognition of the neighboring TATA box present in human U6 snRNA promoters. The
SNAP190 Myb domain also stimulates complex assembly with TBP and Brf2, a subunit
of a snRNA-specific TFIIIB complex. Thus, interactions between the DNA binding
domains of SNAP190 and TBP at juxtaposed promoter elements define the assembly
of a RNA polymerase III-specific preinitiation complex.

PMID: 12621023 [PubMed - indexed for MEDLINE]


---------------------------------------------------------------


2: Biochim Biophys Acta. 2001 Oct 31;1521(1-3):120-5. 

The TATA box and a Myb binding site are essential for anaerobic expression of a
maize GapC4 minimal promoter in tobacco.

Geffers R, Sell S, Cerff R, Hehl R.

Institute of Genetics, Technical University of Braunschweig, Spielmannstrasse 7,
D-38106, Braunschweig, Germany.

The maize GapC4 promoter harbours a complex arrangement of cis-sequences
involved in activation of anaerobic gene expression in tobacco. As shown by
transient expression assays, four copies of a 50 bp anaerobic response element
(ARE) increase anaerobic gene expression compared to the ARE alone. Expression
strength is similar to a 190 bp fragment that contains most sequences required
for anaerobic expression, including the 50 bp ARE. This supports the notion that
redundancy of cis-acting sequences contribute to the anaerobic expression
strength of the promoter. Mutation analysis of the 50 bp ARE revealed that
cis-regulatory sequences are located within 30 bp at the 5' end of the ARE. Of
these 30 bp a putative binding site for a Myb transcription factor is essential
for anaerobic induction. The TATA box of the GapC4 promoter is also required for
anaerobic gene expression and is bound specifically by a recombinant TATA box
binding protein (TBP) from tobacco. A model for anaerobic induction of the GapC4
minimal promoter in tobacco that summarizes the presented data is discussed.

PMID: 11690643 [PubMed - indexed for MEDLINE]


---------------------------------------------------------------


3: Anticancer Drug Des. 1999 Jun;14(3):179-86. 

Effect of ecteinascidin-743 on the interaction between DNA binding proteins and
DNA.

Bonfanti M, La Valle E, Fernandez Sousa Faro JM, Faircloth G, Caretti G,
Mantovani R, D'Incalci M.

Department of Oncology, Istituto di Ricerche Farmacologiche Mario Negri, Milan,
Italy.

Ecteinascidin-743 (ET-743) is a tetrahydroisoquinoline alkaloid isolated from
Ecteinascidia turbinata, a tunicate growing in mangrove roots in Caribbean. It
has been shown to bind in the minor groove of DNA forming covalent adducts by
reaction of the N2 of guanine with the carbinolamine moiety. We investigated
ET-743 ability to inhibit the binding of different transcription factors to
their consensus sequences by using gel shift assays. We have selected three
types of factors: (i) oncogene products such as MYC, c-MYB and Maf; (ii)
transcriptional activators regulated during the cell cycle as E2F and SRF; and
(iii) general transcription factors such as TATA binding protein (TBP), Sp1 and
NF-Y. We observed no inhibition of the binding of Sp1, Maf, MYB and MYC.
Inhibition of DNA binding was observed for TBP, E2F, SRF at ET-743
concentrations ranging from 50 to 300 microM. The inhibition of binding of NF-Y
occurs at even lower concentrations (i.e. 10-30 microM) when the recombinant
subunits of NF-Y are preincubated with the drug, indicating that the inhibition
of NF-Y binding does not require previous ET-743 DNA binding. Since NF-Y is a
trimer containing two subunits with high resemblance to histones H2B and H2A, we
have investigated the effect of ET-743 on nucleosome reconstitution. ET-743
caused a decrease of the nucleosomal band at 100 nM, with the complete
disappearance of the band at 3-10 microM. These data suggest that the mode of
action of this novel anticancer drug is related to its ability to modify the
interaction between some DNA binding proteins and DNA.

PMID: 10500494 [PubMed - indexed for MEDLINE]


---------------------------------------------------------------


4: J Biol Chem. 1996 Nov 8;271(45):28138-45. 

CREB-binding protein activates transcription through multiple domains.

Swope DL, Mueller CL, Chrivia JC.

Department of Pharmacological and Physiological Sciences, Saint Louis University
School of Medicine, St. Louis, Missouri 63104, USA.

CREB-binding protein (CBP) functions as a coactivator molecule for a number of
transcription factors including CREB, c-Fos, c-Jun, c-Myb, and several nuclear
receptors. Although binding sites for these factors within CBP have been
identified, the regions of CBP responsible for transcriptional activation are
unknown. In this report, we show that the N-terminal half of CBP is sufficient
for activation of CREB-mediated transcription and that this region contains a
strong transcriptional activation domain (TAD). Both deletion of this TAD or
sequestering of factors that the TAD binds using a squelching assay were found
to greatly decrease the ability of CBP to activate CREB-mediated transcription.
In vivo studies by others have shown that p300/CBP associates with TBP; using an
in vitro approach, we show the N-terminal TAD binds TBP. We also examined the
ability of the C terminus of CBP to activate transcription using GAL-CBP
chimeras. With this approach, we identified two C-terminal TADs located adjacent
to the c-Fos binding site. In previous studies, cAMP-dependent protein kinase A
(PKA) increased the transcriptional activity of a GAL full-length CBP chimera in
F9 cells, and of the C terminus in PC-12 cells. Here, we demonstrate that PKA
also increased the ability of the N-terminal TADs of CBP to activate
transcription in PC-12 but not F9 or COS-7 cells, suggesting that this
PKA-responsiveness is cell type-specific.

PMID: 8910428 [PubMed - indexed for MEDLINE]


---------------------------------------------------------------


5: EMBO J. 1993 Apr;12(4):1333-41. 

Influence of the v-Myb transactivation domain on the oncoprotein's
transformation specificity.

Frampton J, Kouzarides T, Doderlein G, Graf T, Weston K.

Differentiation Programme, European Molecular Biology Laboratory, Heidelberg,
Germany.

The v-myb-containing viruses AMV and E26 induce the proliferation of
myelomonocytic cells. The E26 Myb protein, by virtue of its fusion to Ets, is
also able to transform multipotent haematopoietic cells (MEPs). We have examined
the biological effects of substituting the v-Myb transactivation domain with the
strong acidic activator domain from the C-terminus of the HSV-1 VP16 protein. In
the absence of Ets, deletion of the transactivation domain destroyed the ability
of v-Myb to stimulate transcription and to transform cells, whilst the
substitution of the VP16 transactivation domain into v-Myb resulted in a greatly
enhanced transactivation potential and altered TATA box binding protein (TBP)
binding properties. In spite of these functional differences, the v-Myb VP16
protein regained the ability to transform myeloid cells with the same
characteristics as wild type v-Myb. A construct encoding v-Myb VP16 fused to
v-Ets was still capable of inducing leukaemia and of transforming both myeloid
cells and MEPs in vitro, although the latter cells exhibited an altered
phenotype. Our results demonstrate that the transformation of myeloid cells by
v-Myb is largely independent of the type and potency of the transactivation
domain it contains, whereas transformation of MEPs by the Myb-Ets fusion protein
has more stringent transactivation requirements of Myb.

PMID: 8467793 [PubMed - indexed for MEDLINE]


---------------------------------------------------------------