HRT Transcription Factor Family
A barley gene encoding a novel DNA-binding protein (HRT) was identified by southwestern
screening with baits containing a gibberellin phytohormone response element from an
alpha-amylase promoter. The HRT gene contains two introns, the larger of which (5722 base pairs
(bp)) contains a 3094-bp LINE-like element with homology to maize Colonist1. In vitro
mutagenesis and zinc- and DNA-binding assays demonstrate that HRT contains three unusual zinc
fingers with a CX8-9CX10CX2H consensus sequence. HRT is targeted to nuclei, and homologues are
expressed in other plants. In vivo, functional tests in plant cells indicate that full-length
HRT can repress expression from certain promoters including the Amy1/6-4 and Amy2/32
alpha-amylase promoters. In contrast, truncated forms of HRT containing DNA-binding domains can
activate, or derepress, transcription from these promoters. Northern hybridizations indicate
that HRT mRNA accumulates to low levels in various tissues. Roles for HRT in mediating
developmental and phytohormone-responsive gene expression are discussed.
Notes: HRT is missed in PlantTFDB.
1 predicted HRT TF peptide,
CDS, and cDNA sequence;
blast HSP, and multiple sequence alignment in
Soy - TFKB.
2 HRT sequences
in SoyDB
Last updated by Dr. Jeff Chen on May 23, 2009.