GT-2: In vivo transcriptional activation activity and definition of novel twin DNA binding domains with reciprocal target sequence selectivity

被引:64
作者
Ni, M
Dehesh, K
Tepperman, JM
Quail, PH
机构
[1] USDA ARS,CTR PLANT GENE EXPRESS,ALBANY,CA 94710
[2] UNIV CALIF BERKELEY,DEPT PLANT BIOL,BERKELEY,CA 94720
关键词
D O I
10.1105/tpc.8.6.1041
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
GT-2 is a novel DNA binding protein that interacts with a triplet of functionally defined, positively acting GT-box motifs (GT1-bx, GT2-bx, and GT3-bx) in the rice phytochrome A gene (PHYA) promoter. Data from a transient transfection assay used here show that recombinant GT-2 enhanced transcription from both homologous and heterologous GT-box-containing promoters, thereby indicating that this protein can function as a transcriptional activator in vivo. Previously, we have shown that GT-2 contains separate DNA binding determinants in its N- and C-terminal halves, with binding site preferences for the GT3-bx and GT2-bx promoter motifs, respectively, Here, we demonstrate that the minimal DNA binding domains reside within dual 90-amino acid polypeptide segments encompassing duplicated sequences, termed trihelix regions, in each half of the molecule, plus 15 additional immediately adjacent amino acids downstream, These minimal binding domains retained considerable target sequence selectivity for the different GT-box motifs, but this selectivity was enhanced by a separate polypeptide segment farther downstream on the C-terminal side of each trihelix region. Therefore, the data indicate that the twin DNA binding domains of GT-2 each consist of a general GT-box recognition core with intrinsic differential binding activity toward closely related target motifs and a modifier sequence conferring higher resolution reciprocal selectivity between these motifs.
引用
收藏
页码:1041 / 1059
页数:19
相关论文
共 86 条
[81]  
TOBIN EM, 1994, SEMIN CELL BIOL, V5, P1
[82]   MUTATIONS OF THE 22-KD AND 27-KD ZEIN PROMOTERS AFFECT TRANSACTIVATION BY THE OPAQUE-2 PROTEIN [J].
UEDA, T ;
WAVERCZAK, W ;
WARD, K ;
SHER, N ;
KETUDAT, M ;
SCHMIDT, RJ ;
MESSING, J .
PLANT CELL, 1992, 4 (06) :701-709
[83]  
VIEIRA J, 1987, METHOD ENZYMOL, V153, P3
[84]   THE YEAST UASG IS A TRANSCRIPTIONAL ENHANCER IN HUMAN HELA-CELLS IN THE PRESENCE OF THE GAL4 TRANS-ACTIVATOR [J].
WEBSTER, N ;
JIN, JR ;
GREEN, S ;
HOLLIS, M ;
CHAMBON, P .
CELL, 1988, 52 (02) :169-178
[85]   TGA1A, A TOBACCO DNA-BINDING PROTEIN, INCREASES THE RATE OF INITIATION IN A PLANT INVITRO TRANSCRIPTION SYSTEM [J].
YAMAZAKI, K ;
KATAGIRI, F ;
IMASEKI, H ;
CHUA, NH .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 1990, 87 (18) :7035-7039
[86]  
YUNES JA, 1994, PLANT CELL, V6, P237, DOI 10.1105/tpc.6.2.237