Plant Transcription Factor Database
Previous version: v3.0
Solanum pimpinellifolium
ARR-B Family
Species TF ID Description
Sopim01g065540.0.1ARR-B family protein
Sopim02g031820.0.1ARR-B family protein
Sopim03g026250.0.1ARR-B family protein
Sopim03g083340.0.1ARR-B family protein
Sopim04g008050.0.1ARR-B family protein
Sopim04g051080.0.1ARR-B family protein
Sopim05g014260.0.1ARR-B family protein
Sopim05g054390.0.1ARR-B family protein
Sopim07g005140.0.1ARR-B family protein
Sopim07g009110.0.1ARR-B family protein
Sopim07g009580.0.1ARR-B family protein
Sopim07g019550.0.1ARR-B family protein
Sopim08g077230.0.1ARR-B family protein
Sopim10g050420.0.1ARR-B family protein
Sopim11g066170.0.1ARR-B family protein
Sopim11g066220.0.1ARR-B family protein
Sopim11g066230.0.1ARR-B family protein
Sopim11g072330.0.1ARR-B family protein
Sopim12g010330.0.1ARR-B family protein
Sopim12g099380.0.1ARR-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