PlantRegMap/PlantTFDB v5.0
Plant Transcription Factor Database
Kalanchoe laxiflora
ARR-B Family
Species TF ID Description
Kaladp0007s0087.1.pARR-B family protein
Kaladp0011s0178.1.pARR-B family protein
Kaladp0011s1020.1.pARR-B family protein
Kaladp0018s0269.1.pARR-B family protein
Kaladp0018s0269.2.pARR-B family protein
Kaladp0018s0269.3.pARR-B family protein
Kaladp0018s0269.4.pARR-B family protein
Kaladp0018s0269.5.pARR-B family protein
Kaladp0029s0020.1.pARR-B family protein
Kaladp0059s0359.1.pARR-B family protein
Kaladp0059s0359.2.pARR-B family protein
Kaladp0059s0359.3.pARR-B family protein
Kaladp0059s0359.4.pARR-B family protein
Kaladp0081s0319.1.pARR-B family protein
Kaladp0101s0149.1.pARR-B family protein
Kaladp0101s0149.2.pARR-B family protein
Kaladp0808s0020.1.pARR-B family protein
Kaladp0808s0020.10.pARR-B family protein
Kaladp0808s0020.2.pARR-B family protein
Kaladp0808s0020.3.pARR-B family protein
Kaladp0808s0020.4.pARR-B family protein
Kaladp0808s0020.5.pARR-B family protein
Kaladp0808s0020.6.pARR-B family protein
Kaladp0808s0020.7.pARR-B family protein
Kaladp0808s0020.8.pARR-B family protein
Kaladp0808s0020.9.pARR-B family protein
Kaladp0809s0083.1.pARR-B family protein
ARR-B Family Introduction

The Arabidopsis genome codes for 22 response regulators (ARRs), 12 of which contain a Myb-like DNA binding domain called ARRM (type B). The remainder (type A) possess no apparent functional unit other than a signal receiver domain containing two aspartate and one lysine residues (DDK) at invariant positions, and their genes are transcriptionally induced by cytokinins without de novo protein synthesis. The type B members, ARR1 and ARR2, bind DNA in a sequence-specific manner and work as transcriptional activators.

Here we present evidence that ARR1 mediates a cytokinin signal, probably through its NH2-terminal signal receiver domain, and transactivates ARR6, which is immediately responsive to cytokinins. A paralogous response regulator, ARR2, shows almost identical characteristics to ARR1, suggesting a functional overlap. Residual cytokinin responses observed with the arr1-1 mutant may have been provided by ARR2. In addition to ARR6, other type A member genes, including ARR4, ARR5, ARR7, ARR8, and ARR9, were also activated by DEX at various levels in 35S::ARR1DDK::GR plants, suggesting that all the immediate cytokinin-responsive genes belonging to this group are directly activated by ARR1. Also, other cytokinin-responsive genes whose promoter regions contain the ARR1 recognition sequences are possibly transactivated by ARR1. A screening for ARR1 target genes using transgenic 35S::ARR1-DDK::GR plants will shed light on the whole view of the early cytokinin signal transduction pathway. We conclude that ARR1 is a principal transcription factor-type response regulator that is involved in an early step of cytokinin signal transduction, possibly as a partner of the sensor histidine kinase CRE1.

Hiroe Sakai, Takashi Honma, Takashi Aoyama, Shusei Sato, Tomohiko Kato, Satoshi Tabata, Atsuhiro Oka
ARR1, a Transcription Factor for Genes Immediately Responsive to Cytokinins
Science, Vol 294, Issue 5546, 1519-1521, 16 November 2001