Dc3 is a carrot lea class gene that is abundantly expressed during somatic and zygotic embryogenesis. Its expression is normally embryo-specific and also can be induced by abscisic acid. The regulatory elements mediating the embryo-specific expression of Dc3 reside within the proximal promoter region (-117 to +26), which is also essential for ABA-induced expression. In this study, an optimized version of the yeast one-hybrid system has been used to clone factors that bind to the promoter region of the Dc3 gene. Twenty-five million yeast transformants were screened in a single experiment, and nine independent cDNA clones were isolated from a sunflower library that encode proteins that specifically bind to functional cis-regulatory elements in the Dc3 promoter. Analysis of these clones showed that they are derived from three different mRNA species that encode two basic leucine zipper proteins. The basic regions of these proteins, named DPBF-1 and 2 (Dc3 Promoter-Binding Factor-1 and 2), respectively, are nearly identical to each other and are similar to the plant G-box binding factor GBF-4. Outside the basic region, however, DPBF-1 and 2 diverge significantly from each other and from other known factors. Both factors have transcriptional activity in yeast, and bind to DNA as dimers. Unlike other plant bZIP factors, DPBF-1 and 2 recognize sequences containing the ACACNNG core. Cloning of these factors demonstrates the power of the one-hybrid approach when optimally applied.

Despite much development, there remains dosimetric uncertainty in the surface and build-up regions in intensity-modulated radiation therapy treatment plans for head and neck cancers. Experiments were performed to determine the dosimetric discrepancies in the surface and build-up region between the treatment planning system (TPS) prediction and experimental measurement using radiochromic film. A head and neck compression film phantom was constructed from two semicylindrical solid water slabs. Treatment plans were generated using two commercial TPSs (PINNACLE3 and CORVUS) for two cases, one with a shallow (approximately 0.5 cm depth) target and another with a deep (approximately 6 cm depth) target. The plans were evaluated for a 54 Gy prescribed dose. For each case, two pieces of radiochromic film were used for dose measurement. A small piece of film strip was placed on the surface and another was inserted within the phantom. Overall, both TPSs showed good agreement with the measurement. For the shallow target case, the dose differences were within +/- 300 cGy (5.6% with respect to the prescribed dose) for PINNACLE3 and +/- 240 cGy (4.4%) for CORVUS in 90% of the region of interest. For the deep target case, the dose differences were +/- 350 (6.5%) for PINNACLE3 and +/- 260 cGy (4.8%) for CORVUS in 90% of the region of interest. However, it was found that there were significant discrepancies from the surface to about 0.2 cm in depth for both the shallow and deep target cases. It was concluded that both TPSs overestimated the surface dose for both shallow and deep target cases. The amount of overestimation ranges from 400 to 1000 cGy (approximately 7.4% to 18.5% with respect to the prescribed dose, 5400 cGy).

Methyl jasmonate (MeJA) treatment increases the levels of plant secondary metabolites, including ginsenosides, which are considered to be the main active compounds in ginseng (Panax ginseng C.A. Meyer). To create a ginseng gene resource that contains the genes involved in the biosynthesis of secondary metabolites, including ginsenosides, we generated 3,134 expression sequence tags (ESTs) from MeJA-treated ginseng hairy roots. These ESTs assembled into 370 clusters and 1,680 singletons. Genes yielding highly abundant transcripts were those encoding proteins involved in fatty acid desaturation, the defense response, and the biosynthesis of secondary metabolites. Analysis of the latter group revealed a number of genes that may be involved in the biosynthesis of ginsenosides, namely, oxidosqualene cyclase (OSC), cytochrome P450, and glycosyltransferase. A novel OSC gene was also identified by this analysis. RNA gel blot analysis confirmed that transcription of this OSC gene, along with squalene synthase (SS) and squalene epoxidase (SE) gene transcription, is increased by MeJA treatment. This ginseng EST data set will also provide important information on the genes that are involved in the biosynthesis of other secondary metabolites and the genes that are responsive to MeJA treatment.

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The complete nucleotide sequence of the chloroplast genome of potato Solanum tuberosum L. cv. Desiree was determined. The circular double-stranded DNA, which consists of 155,312 bp, contains a pair of inverted repeat regions (IRa, IRb) of 25,595 bp each. The inverted repeat regions are separated by small and large single copy regions of 18,373 and 85,749 bp, respectively. The genome contains 79 proteins, 30 tRNAs, 4 rRNAs, and unidentified genes. A comparison of chloroplast genomes of seven Solanaceae species revealed that the gene content and their relative positions of S. tuberosum are similar to the other six Solanaceae species. However, undefined open reading frames (ORFs) in LSC region were highly diverged in Solanaceae species except N. sylvestris. Detailed comparison was identified by numerous indels in the intergenic regions that were mostly located in the LSC region. Among them, a single large 241-bp deletion, was not associated with direct repeats and found in only S. tuberosum, clearly discriminates a cultivated potato from wild potato species Solanum bulbocastanum. The extent of sequence divergence may provide the basis for evaluating genetic diversity within the Solanaceae species, and will be useful to examine the evolutionary processes in potato landraces.