Plant Transcription Factor Database
Previous version: v1.0, v2.0, v3.0
Capsella rubella
ARR-B Family
Species TF ID Description
Carubv10003421mARR-B family protein
Carubv10004540mARR-B family protein
Carubv10004554mARR-B family protein
Carubv10006317mARR-B family protein
Carubv10007581mARR-B family protein
Carubv10007858mARR-B family protein
Carubv10011077mARR-B family protein
Carubv10013107mARR-B family protein
Carubv10018465mARR-B family protein
Carubv10019443mARR-B family protein
Carubv10020133mARR-B family protein
Carubv10022138mARR-B family protein
Carubv10022837mARR-B family protein
Carubv10026052mARR-B family protein
Carubv10026054mARR-B family protein
Carubv10026091mARR-B family protein
Carubv10027854mARR-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