Light-regulated expression of the pea plastocyanin gene is mediated by elements within the transcribed region of the gene

Expression of the pea plastocyanin gene ( PetE ) is regulated by light in both pea and transgenic tobacco plants. However, the PetE promoter with the 5' untranslated leader region does not direct light-regulated expression of the GUS reporter gene in transgenic tobacco. This suggested that sequences downstream of the translation start of the PetE gene are required for light-regulated expression. To investigate this possibility the expression of a series of chimeric gene constructs in transgenic tobacco plants was examined to assess the contributions of the promoter, the 5' untranslated leader region, the coding region and the 3' region of the PetE gene to light-regulated expression. Both the coding region and the 5' untranslated leader region of the PetE gene were found to be required for full light regulation. Full light regulation of chimeric gene constructs containing the cauliflower mosaic virus (CaMV) 35S promoter required the deletion of CaMV 5' leader and polylinker sequences from the constructs. The presence of CaMV and polylinker sequences at the 5' end of the PetE leader masked the light regulation directed by the transcribed region of the pea PetE gene.     

Functional Characterization of cis-Elements Conferring Vascular Vein Expression of At4g34880 Amidase Family Protein Gene in Arabidopsis

The expression of At4g34880 gene encoding amidase in Arabidopsis was characterized in this study. A promoter region of 1.5 kb on the upstream of the start codon of the gene (referred as AmidP) was fused with uidA (GUS) reporter gene, and transformed into Arabidopsis plant for determining its spatial expression. The results indicated that AmidP drived GUS expression in vascular system, predominately in leaves. Truncation analysis of AmidP demonstrated that VASCULAR VEIN ELEMENT (VVE) motif with a region of 176 bp sequence (−1500 to −1324) was necessary and sufficient to direct the vascular vein specific GUS expression in the transgenic plant. Tandem copy of VVE increased vascular system expression, and 5′- and 3′- deletions of VVE motif in combination with a truncated −65 CaMV 35S minimal promoter showed that 11bp cis-acting element, naming DOF2 domain, played an essential role for the vascular vein specific expression. Meanwhile, it was also observed that the other cis-acting elements among the VVE region are also associated with specificity or strength of GUS activities in vascular system.     

毛白杨PtSEP2基因启动子克隆和瞬时表达特性分析

利用PCR技术从毛白杨基因组DNA中扩增获得花器官发育相关的SEPALLATA2类似基因PtSEP25′侧翼约2.3kb的一段序列,经PlantCARE序列分析表明,该序列中含有启动子特征的保守序列及多种光应答元件,初步推测其为PtSEP2基因启动子.进一步以GUS为报告基因,构建了pPtSEP2 promoter::...     

The TACPyAT repeats in the chalcone synthase promoter of Petunia hybrida act as a dominant negative cis-acting module in the control of organ-specific expression

Analysis of the expression of the GUS reporter gene driven by various regions of the Petunia hybrida chalcone synthase (chsA) promoter revealed that the developmental and organ-specific expression of the chsA gene is conferred by a TATA proximal module located between -67 and -53, previously designated as the TACPyAT repeats. Histochemical analysis of GUS reporter gene expression revealed that the organ-specific 67 bp promoter fragment directs the same cell-type specificity as a 530 bp promoter, whereas additional enhancer sequences are present within the more TATA distal region. Moreover, the region between -800 and -530 is also involved in extending the cell-type specificity to the trichomes of flower organs and of young seedlings. The mechanism by which the TACPyAT repeats modulate expression during plant development was studied by analysing the expression of the GUS gene driven by chimeric promoters consisting of the CaMV 35S enhancer (domain B, -750 to -90) fused to various chsA 5' upstream sequences. Detailed enzymatic and histochemical analysis revealed that in the presence of the TACPyAT module the CaMV 35S region only enhances GUS activity in those organs in which the chsA promoter is normally active. Furthermore, this analysis shows that enhancement in the presence of the CaMV 35S domain B is accomplished by increasing the number of cell types expressing the GUS gene within the organ, rather than enhancement of the chsA cell-type-specific expression within these organs. Deletion of the TACPyAT sequences in the chimeric promoter construct completely restores the well-documented CaMV 35S domain B cell-type specificity, showing that the TACPyAT module acts as a dominant negative cis-acting element which controls both organ and developmental regulation of the chsA promoter activity.     

Abscisic acid-responsive sequences from the em gene of wheat.

We demonstrate that a chimeric gene containing the beta-glucuronidase (GUS) reporter gene linked to a 646-base pair 5' fragment (-554 to +92) from the abscisic acid (ABA)-regulated Em gene from wheat is correctly expressed in transgenic tobacco. We observe high activity only in embryos of mature seeds, and immature seeds cultured on ABA show enhanced expression. Using a rice transient assay, we identify a 260-base pair fragment (-168 to +92) that accounts for the ABA-specific 15-fold to 20-fold increase in GUS expression. A 50-base pair sequence (-152 to -103) fused 5' in either orientation to a truncated cauliflower mosaic virus promoter (35S) increases GUS activity threefold in the presence of ABA. Insertion of the Em 5'-untranslated region (+6 to +86) between the 35S promoter and the ATG of GUS results in a 10-fold increase in GUS activity in the absence of ABA. These results suggest the following two functional fragments of the Em 5' region: an ABA response element from -152 to -103 and an element between +6 and +86 that quantitatively increases the ABA response.     

The effects of promoter on transient expression in conifer cell lines

Summary Protoplasts from suspension cultures of somatic embryos of white spruce (Picea glauca Moench Voss) were electroporated with plasmids containing the chimeric genes for chloramphenicol acetyl transferase (CAT) or -glucuronidase (GUS), under control of one of three promoters. Transient CAT gene expression of approximately equal magnitude resulted when the CAT gene was fused to either the cauliflower mosaic virus (CaMV) 35S promoter or the nopaline synthase (NOS) promoter. When the CAT gene was fused to a tandem repeat CaMV 35S promoter (pPBI-363), CAT enzyme activity compared to NOS or 35S promoters increased up to eightfold (cell line WS-34), and were up to 100-fold greater than control (electroporated without plasmid). Comparatively, protoplasts of black spruce (Picea mariana Mill) and jack pine (Pinus banksiana Lamb.), electroporated with pPBI-363, produced increases in CAT activity compared to control of 90-fold and 70-fold, respectively. White spruce (WS-34) protoplasts were subsequently electroporated with the GUS gene fused to the tandem repeat CaMV 35S promoter. Comparatively, GUS enzyme activity increased up to tenfold compared to GUS fused to a CaMV 35S promoter. The results indicated that transient expression of the CAT and GUS genes was influenced by the type of promoter and cell line used, as well as by electroporation conditions.NRCC No. 30498