TOBFAC: The database of tobacco transcription factors
Family: Trihelix
Minimum number of tobacco Trihelix genes: 40
Count of tobacco Trihelix sequences: 42
Pfam accession: trihelix
SHOULD possess trihelix domain
The trihelix domain is characteristic of the trihelix family. The trihelix domain was extracted from known members of this family in Nicotiana tabacum, Arabidopsis thaliana and Oryza sativa.
GT-2 is a plant transcriptional activator that contains two separate, but similar, trihelix DNA-binding domains. GT-1 is similar to GT-2, although it contains only one of such domains. cDNAs that encode GT-2 were isolated from rice (OS-GT2) and Arabidopsis (AT-GT2). Evidence is presented for the existence of an Arabidopsis gene family that is structurally related to AT-GT2. Two members of this GT2-like family, AT-GTL1 and AT-GTL2, have been isolated and characterized. Their sequences suggest that they evolved by a recent gene duplication event. Both AT-GT2 and AT-GTL genes contain an intron in the amino-terminal trihelix motif, indicating that this DNA-binding domain resulted from exon shuffling. RNA gel blot analysis using AT-GTL1 as a probe revealed four transcripts in the aerial part of the plant. All mRNA levels were significantly higher in siliques, suggesting that this gene family may function in fruit and/or seed development. To date, DNA-binding proteins characterized by the trihelix motif have been described only in plants, and may therefore be involved in plant-specific processes. Our results show that in Arabidopsis thaliana, the trihelix motif is not restricted to the GT-1 and GT-2 DNA-binding proteins.
Nagano, Y. Several features of the GT-factor trihelix domain resemble those of the Myb DNA-binding domain. Plant Physiol. 2000. 124(2):491-4 PMID: 11027698
Nagano, Y; Inaba, T; Furuhashi, H; Sasaki, Y. Trihelix DNA-binding protein with specificities for two distinct cis-elements: both important for light down-regulated and dark-inducible gene expression in higher plants. J. Biol. Chem. 2001. 276(25):22238-43 PMID: 11301338
Smalle, J; Kurepa, J; Haegman, M; Gielen, J; Van Montagu, M; Van Der Straeten, D. The trihelix DNA-binding motif in higher plants is not restricted to the transcription factors GT-1 and GT-2. Proc. Natl. Acad. Sci. U.S.A. 1998. 95(6):3318-22 PMID: 9501260
Zhou, DX. Regulatory mechanism of plant gene transcription by GT-elements and GT-factors. Trends Plant Sci 1999. 4(6):210-214 PMID: 10366876
Number of contigs: 37
Number of singlets: 7
Number of N terminal – 4
Number of C terminal – 2
Number of full – 36
Total minimum number – 40
| Family | Genbank ID | Name |
Paul J Rushton
Marta T. Bokowiec
Xianfeng (Jeff) Chen
Thomas (Tom) W Laudeman
Jennifer F. Brannock
Michael P. Timko