Desai, Mintu .
Light Regulated Expression of PEX11b Gene in Arabidopsis.
Peroxisome division is poorly understood in higher organisms. The PEX11 peroxisome membrane proteins are the only known factors to promote peroxisome division and multiplication specifically in plants (Orth Travis et al., 2006). A shift from dark to light remarkably induces elongation of the peroxisome and subsequent division and multiplication in Arabidopsis seedlings. We determined the condition and stages of PEX11b expression in Arabidopsis. The expression of PEX11b gene is increased dramatically with increase in time points after dark to light shift of Arabidopsis seedlings. PEX11b is known to be important in peroxisome division among the other members of its family. PEX11b promoter was analyzed for the presence of typical light response elements (LRE’s) and several of them were found. A minimal region (~250bp) of the PEX11b promoter was able to form a DNA: Protein complex. Biochemical and genetic data indicated PHYA and CRY1 photoreceptors to play a significant role in regulation of PEX11b gene expression. A careful examination of the downstream components of PHYA signaling pathway revealed PAT1 (Phytochrome A Transduction) and HYH (HY5 Homolog) to be involved in transcriptional activation of PEX11b. In the present work we demonstrate in vitro the physical interaction of all the three different forms of bacterially expressed HYH protein and the 250bp PEX11b promoter fragment, and further establish this interaction and its important role through genetic evidence. HYH is a positive regulator of photomorphigenesis (Holm et al., 2002). Peroxisomes are essential during seed germination and early stages of growth (Hu et al., 2002). Search of other nuclear proteins that regulate PEX11b are important, to understand how light exerts its function in peroxisome proliferation.
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1 - MSU DOE-PRL, Plant, 306 Plant Biology Bldg, East Lansing, East lansing, Michigan, 48824, USA
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM