TY - JOUR
T1 - Coiled-coil structure-mediated dimerization of template activating factor-I is critical for its chromatin remodeling activity
AU - Miyaji-Yamaguchi, Mary
AU - Okuwaki, Mitsuru
AU - Nagata, Kyosuke
N1 - Funding Information:
The authors thank Drs M. Sakurai and N. Yoshie for their help with computer-assisted structure analysis. This work was supported, in part, by a Grant-in-Aid from the Ministry of Education, Science, Sports and Culture of Japan, and by grants from Biodesign Research Program of RIKEN (Institute of Physical and Chemical Research, Japan) and from Nagase Science and Technology Foundation.
PY - 1999/7/9
Y1 - 1999/7/9
N2 - Template activating factor-I (TAF-I)α and TAF-Iβ have been identified as the host factors that activate DNA replication of the adenovirus genome complexed with viral basic core proteins (Ad core). TAF-I causes a structural change of the Ad core, thereby stimulating not only replication but also transcription from the Ad core DNA in vitro. TAF-I also activates transcription from the reconstituted chromatin consisting of DNA fragments and purified histones through chromatin remodeling. Although the carboxyl-terminal region, which is highly rich in acidic amino acids, is essential for the TAF-I activity, it remains unclear how other parts are involved in its activity. The native TAF-I isolated from HeLa cells exists as either hetero- or homo-oligomer. Here, we have demonstrated by cross-linking assays that most of TAF-I exists as a dimer. Analyses using deletion mutant TAF-I proteins revealed that the amino-terminal region of TAF-I common to both α and β is essential for dimerization. This region is predicted to form a coiled-coil structure. Indeed, mutations disrupting this putative structure abolished the dimerization capability and reduced the TAF-I activity in the Ad core DNA replication assay. Furthermore, we found that TAF-I mutants lacking the acidic tail act in a dominant-negative manner in this assay. These observations strongly suggest that the dimerization of TAF-I is important for its activity.
AB - Template activating factor-I (TAF-I)α and TAF-Iβ have been identified as the host factors that activate DNA replication of the adenovirus genome complexed with viral basic core proteins (Ad core). TAF-I causes a structural change of the Ad core, thereby stimulating not only replication but also transcription from the Ad core DNA in vitro. TAF-I also activates transcription from the reconstituted chromatin consisting of DNA fragments and purified histones through chromatin remodeling. Although the carboxyl-terminal region, which is highly rich in acidic amino acids, is essential for the TAF-I activity, it remains unclear how other parts are involved in its activity. The native TAF-I isolated from HeLa cells exists as either hetero- or homo-oligomer. Here, we have demonstrated by cross-linking assays that most of TAF-I exists as a dimer. Analyses using deletion mutant TAF-I proteins revealed that the amino-terminal region of TAF-I common to both α and β is essential for dimerization. This region is predicted to form a coiled-coil structure. Indeed, mutations disrupting this putative structure abolished the dimerization capability and reduced the TAF-I activity in the Ad core DNA replication assay. Furthermore, we found that TAF-I mutants lacking the acidic tail act in a dominant-negative manner in this assay. These observations strongly suggest that the dimerization of TAF-I is important for its activity.
KW - Acidic protein
KW - Adenovirus
KW - Chromatin
KW - Cross-linking
KW - Replication
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U2 - 10.1006/jmbi.1999.2898
DO - 10.1006/jmbi.1999.2898
M3 - Article
C2 - 10390352
AN - SCOPUS:0033538530
VL - 290
SP - 547
EP - 557
JO - Journal of Molecular Biology
JF - Journal of Molecular Biology
SN - 0022-2836
IS - 2
ER -