Regulatory elements in vivo in the promoter of the abscisic acid responsive gene rab17 from maize

Abstract

The rab17 gene from maize is transcribed in late embryonic development and is responsive to abscisic acid and water stress in embryo and vegetative tissues. In vivo footprinting and transient transformation of rab17 were performed in embryos and vegetative tissues to characterize the cis-elements involved in regulation of the gene. By in vivo footprinting, protein binding was observed to nine elements in the promoter, which correspond to five putative ABREs (abscisic acid responsive elements) and four other sequences. The footprints indicated that distinct proteins interact with these elements in the two developmental stages. In transient transformation, six of the elements were important for high level expression of the rab17 promoter in embryos, whereas only three elements were important in leaves. The cis-acting sequences can be divided in embryo-specific, ABA-specific and leaf-specific elements on the basis of protein binding and the ability to confer expression of rab17. We found one positive, new element, called GRA, with the sequence CACTGGCCGCCC. This element was important for transcription in leaves but not in embryos. Two other non-ABRE elements that stimulated transcription from the rab17 promoter resemble previously described abscisic acid and drought-inducible elements. There were differences in protein binding and function of the five ABREs in the rab17 promoter. The possible reasons for these differences are discussed. The in vivo data obtained suggest that an embryo-specific pathway regulates transcription of the rab genes during development, whereas another pathway is responsible for induction in response to ABA and drought in vegetative tissues.

Abscisic Acid Induces CBF Gene Transcription and Subsequent Induction of Cold-Regulated Genes via the CRT Promoter Element

“…This is the first direct demonstration of ABA-dependent signaling through the CRT/ DRE in Arabidopsis. However, in maize it is interesting to note that two DRE-like elements (DRE1 and DRE2), which are inducible by ABA, have been identified in the RAB17 gene promoter (Busk et al, 1997). ABA also up-regulates the transcript levels of DBF1 and DBF2, trans-acting factors that bind to DRE2 (Kizis and Pages, 2002).…”

Phylogenetic Analysis of 5′-Noncoding Regions From the ABA-Responsive rab16/17 Gene Family of Sorghum, Maize and Rice Provides Insight Into the Composition, Organization and Function of cis-Regulatory ModulesSequence data from this article have been deposited with the EMBL/GenBank Data Libraries under accession no. AY177889.

“…For example, an 2003). Recent progress on sequencing plant genomes is ‫-053ف‬bp region of the promoter of maize rab17 contains creating a similar opportunity to identify and undera minimum of nine TF-binding sites that mediate restand the function of noncoding regulatory sequences sponses to ABA and dehydration and regulate gene expression during seed and vegetative development (Busk et al 1997). Cis-elements are also important to define because Sequence data from this article have been deposited with the phenotypic variation can be caused by mutations in these EMBL/GenBank Data Libraries under accession no.…”

“…Maize rab17, a well-characterized ABAComparison of highly diverged species reduces the responsive gene (Busk et al 1997; Busk and Pages 1998; problem of random sequence matching; however, studKizis and Pages 2002), was used as a reference to deteries of more closely related species often provide the mine if phylogenetic analysis was producing useful results. The identification of previously discovered and most information since extended evolution of regula-Phylogenetic Analysis of Grass rab Genes (Applied Biosystems) to allow amplification of ‫-001ف‬bp prodseveral new putative regulatory elements in the current ucts of similar GC and Tm characteristics.…”

“…Sequence matches outside of CNS are colored blue. Biochemically defined TF-binding sites in maize (Busk et al 1997) are boxed with thick lines and labeled above the Zmrab17 sequence, while putative regulatory elements identified through public database searches are boxed with thin lines and labeled below the Osrab16A2 sequence. Dashes indicate a gap in the alignment, while asterisks (*) represent a sequence that can align on either side of an INDEL.…”

“…are sufficient to modulate basal and ABA-induced exPhylogenetic analysis relies on the identification of conserved sequences among two or more genes that pression of this gene in both seeds and vegetative tissues (Busk et al 1997). Therefore, our comparison of nonevolved from a common progenitor: Divergence of homologous genes can occur via speciation or following coding sequences focused on ‫005ف‬ bp upstream of the coding region.…”