Withers, John C. , Wyatt, Sarah .
Gravity persistent signal 1 reveals two novel cytochrome P450s involved in plant gravitropism.
Understanding gene expression that occurs during gravitopism is important for studying the processes that link the perception of gravity to the growth response. Arabidopsis plants with a mutation in the GRAVITY PERSISTENT SIGNAL (GPS)1 locus show a “no response” phenotype during gravistimulation experiments. GPS1 encodes CYP705A22, a cytochrome P450 protein (P450) of unknown function. Microarray data collected from Arabidopsis root tips indicated that CYP705A5 is increased following a gravity stimulus in roots. The wild type CYP705A22 gene was transformed into the gps1 mutant background, and subsequent gravity stimulation experiments conducted on the transgenic plants showed that the transformation successfully rescued the mutant phenotype. An expression profile was generated for CYP705A5 using real-time quantitative PCR, and the data indicate that CYP705A5 is up-regulated nearly five fold within minutes of gravity stimulation. Reporter gene constructs that link the CYP705A5 gene to the green fluorescent protein (GFP) have shown that CYP705A5 is expressed in the root zones of elongation and maturation. Computer modeling of the catalytic domain and screening of potential substrates has generated a list of 130 compounds that may have the ability to bind to CYP705A22 and CYP705A5, and many of the compounds are phenylpropanoid derivatives. Protein expression constructs were created and expressed in cell culture to determine the specific biological substrate for each. (Supported by NASA: NAG2-1608 and NSF: 0618506 to SEW)
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1 - Ohio University, Environmental and Plant Biology, 317 Porter Hall, Athens, Ohio, 45701, USA
2 - Ohio University, Environmental and Plant Biology
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM