Poster: Transcription Regulation
Abs #
1032: Characterization of cis-regulatory regions involved in transcriptional regulation of the abscisic acid-insensitive3 locus in Arabidopsis thaliana
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Presenter: |
Ng, Wang Kit , danny@idmb.tamu.edu |
Authors | Ng, Wang Kit (A) Chandrasekharan, Mahesh B. (A) Hall, Timothy C. (A) | | Affiliations: |
(A): Institute of Developmental and Molecular Biology and Department of Biology, Texas A&M University
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The Phaseolus vulgaris ABI3-like factor (PvALF) belongs to a family of embryo-specific transcriptional activators that includes maize viviparous1 (VP1) and Arabidopsis abscisic acid-insensitive3 (ABI3) proteins. While itself being seed-specific, PvALF is responsible for the abscisic acid (ABA)-mediated seed-specific expression of the b-phaseolin (phas) gene in P. vulgaris. Since ABI3 is involved in ABA-mediated expression of several seed-specific protein genes in Arabidopsis, we conjectured that understanding how transcription of ABI3 is regulated will provide insight to the mechanism by which PvAlf controls phas expression. The 5.1 kb ABI3 upstream sequence (-4744abi3), which includes a 406 bp 5’ untranslated region (UTR), was PCR-amplified from the Arabidopsis genome. Wild type or truncated abi3 promoter fragments were transcriptionally fused to the b-glucuronidase (gus) reporter. The functionality of promoter constructs was initially tested by transient expression following biolistic bombardment of P. vulgaris cotyledons and subsequently by stable transformation of Arabidopsis. Promoter deletion analysis revealed several important cis-regulatory regions governing abi3 expression. These include a minimal seed-specific region (-996 to -477) and two positive regulatory regions (-3714 to -2145; -2145 to -996). In addition, the 406 bp 5’ UTR of abi3 was found to play a negative regulatory role in abi3 expression. In silico analysis using the online PlantCARE program identified several putative cis-regulatory elements within the -996 to -477 minimal seed-specific region. In vivo dimethyl sulfate footprinting is underway to create a high-resolution map of cis-element(s) occupied during transcription of abi3.
Supported by NSF grant MCB 99-74706
