Identification of a novel cis‐regulatory element for UV‐B‐induced transcription in Arabidopsis

Abstract

SummaryUltraviolet-B light (UV-B) regulates the expression of genes in a wavelength-and fluence rate-dependent fashion. A signaling pathway consisting of CONSTITUTIVE PHOTOMORPHOGENESIS 1 (COP1) and UV RESISTANCE LOCUS 8 (UVR 8) mediates responsiveness to longer wavelength, low intensity UV-B lightactivating, for example, HY5 gene expression. By contrast, transcription of another group of genes, including ANAC13, modulated by shorter wavelength, higher intensity UV-B is controlled by a yet unknown and largely COP1-independent signaling cascade. Here we provide evidence by promoter deletion analysis, and characterization of genetic mutants displaying aberrant expression patterns, that two cis-regulatory elements, designated MRE ANAC13 and UVBox ANAC13 , are required for maximal UV-B induction of the ANAC13 gene in transgenic plants. These elements are located in the proximal 150-bp region of the ANAC13 promoter. They show no significant similarity to each other; the putative MRE ANAC13 (-AACCTT-) is closely related to MRE CHS (-AACCTA-) found in the CHALCONE SYNTHASE (CHS) gene, whereas UVBox ANAC13 (with core sequence CAAG) represents a novel cis-regulatory element. The novel UVBox ANAC13 sequence is significantly enriched in the promoter region of a subset of UV-B-induced genes with similar activation properties as ANAC13.In addition, we demonstrate that expression of a chimeric gene containing only the dimerized 12-mer containing UVBox ANAC13 fused to a minimal CaMV35S promoter/luciferase reporter is (i) efficiently induced by shorter wavelength, higher intensity UV-B, but (ii) does not respond either to longer wavelength UV-B and red light or (iii) to abscisic acid treatment and osmotic, salt, heat and cold stresses.

The Responses of Arabidopsis Early Light-Induced Protein2 to Ultraviolet B, High Light, and Cold Stress Are Regulated by a Transcriptional Regulatory Unit Composed of Two Elements

“…Consistent with microarray analysis (Kilian et al, 2007) and reporter assays done by other laboratories (Safrany et al, 2008), our experiments showed that a pulse UV-B under continuous white light caused a strong increase (77.2-fold: from 8.0 3 10 2 at 0 h to 6.2 3 10 4 cpm seedling -1 at 3 h) in luciferase activity in plants carrying luciferase under the control of the native ELIP2 promoter. This peak of activity occurred 3 h after the UV-B pulse (Fig.…”

Negative feedback regulation of UV-B–induced photomorphogenesis and stress acclimation in Arabidopsis

“…We previously analyzed specific responses to UV-B at the level of transcriptomic change (6,11) and confirmed the transcriptional activation of several genes using the luciferase reporter (including At5g52250; see below) (16). We selected two genes induced early in response to narrowband UV-B irradiance encoding highly similar WD40-repeat proteins for detailed analysis.…”

The Membrane-Bound NAC Transcription Factor ANAC013 Functions in Mitochondrial Retrograde Regulation of the Oxidative Stress Response in Arabidopsis

“…The ANAC013 promoter also contained the MDM cis-regulatory element (CTTGGAGAAGAAG; see Supplemental Table 3 online) that overlapped with two ANAC013 promoter elements shown previously to be required for UV-B induction of ANAC013 (Safrany et al, 2008). To examine the effect of ANAC013 on its own promoter activity, ProANAC013 fused to b-glucuronidase (GUS) constructs (ProANAC013:GUS) were transformed in 35S:ANAC013-6 plants.…”