Plant Transcription factor database - Universität Potsdam
version: 3.0

Trihelix Family


Smalle et al. 1998: 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.

Members of this family
  SHOULD possess trihelix domain

Domain alignments

This family is also present in:


General references

Nagano, Y. 2000. Several features of the GT-factor trihelix domain resemble those of the Myb DNA-binding domain. Plant Physiol. 124(2):491-4 PUBMEDID:11027698
Nagano, Y; Inaba, T; Furuhashi, H; Sasaki, Y. 2001. 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. 276(25):22238-43 PUBMEDID:11301338
Smalle, J; Kurepa, J; Haegman, M; Gielen, J; Van Montagu, M; Van Der Straeten, D. 1998. 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. 95(6):3318-22 PUBMEDID:9501260
Zhou, DX. 1999. Regulatory mechanism of plant gene transcription by GT-elements and GT-factors. Trends Plant Sci 4(6):210-214 PUBMEDID:10366876