Disease relevance of ARR1

• Constitutive expression of ARR1 under the control of the 35S cauliflower mosaic virus promoter enhanced wild-type OsNSHB2 promoter activity, but had no effect on the activity of the mutated promoter in the absence of cytokinin [1].

High impact information on ARR1

• The short signalling circuit reaches the nuclear target genes by enabling nuclear response regulators ARR1, ARR2 and ARR10 as transcription activators [2].
• We used a steroid-inducible system to show that the transcription factor-type response regulator ARR1 directs transcriptional activation of the ARR6 gene, which responds to cytokinins without de novo protein synthesis [3].
• This fact, together with characteristics of ARR1-overexpressing plants and arr1 mutant plants, indicates that the phosphorelay to ARR1, probably from CRE1, constitutes an intracellular signal transduction occurring immediately after cytokinin perception [3].
• This motif is highly similar to the optimal DNA-binding sites for ARR1/ARR2, type-B ARRs that have been implicated in the transcriptional elevation of the type-A ARRs [4].
• These ARR family members were phylogenetically classified into three sub-families, the largest of which includes the well-characterized ARR1, ARR2, and ARR11 [5].

Biological context of ARR1

• Both ARR1 and ARR2 promoted expression of a reporter gene in plant cells through their own target sequence [6].
• The genes coding for the response regulators ARR1 and ARR2 have previously been identified by in silico screening of an expression sequence tag database and subsequent cloning from both Arabidopsis cDNA and genomic libraries [6].

Associations of ARR1 with chemical compounds

• In addition, this signal transfer process appears to participate in cross-talk with signaling systems that respond to daylight and another phytohormone, ethylene, through an intracellular pool of several ARR1-like molecular species and the AHP components [7].

Other interactions of ARR1

• ARR1 and ARR2 were localized in the nuclei of plant cells regardless of the presence or absence of their signal receiver domain [6].
• The signal is then transferred via histidine-containing phosphotransfer factors, AHPs, to transcription-factor-type response regulators, such as ARR1, which execute the signal-dependent transactivation of primary cytokinin-responsive genes, including those for other types of response regulator [8].

References