Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.31 (beta-glucuronidase)
 7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The alcohol dehydrogenase gene (NtADH) was previously isolated from tobacco BY2 suspension cultured cell. Expression of this gene was dramatically increased only during the early stationary phase, and the 5'-untranslated region (5'-UTR) was hypothesized to be involved in the stimulatory effect at the post-transcriptional level. In this paper, we investigated whether the NtADH 5'-UTR possesses the ability to positively enhance gene expression at the translational level. For easily estimating translational efficiency, we used beta-glucuronidase (GUS) gene as a reporter and tobacco BY2 cell, Arabidopsis thaliana T87 cell, and rice Oryza sativa suspension cultured cells as host cells in a transient assay system. Compared with the control plasmid pBI221, insertion of the NtADH 5'-UTR enhanced GUS expression levels about 30- to 100-fold and 30- to 60-fold in transiently transformed BY2 and T87 cells, respectively. However, in transiently transformed O. sativa cells, expression was barely enhanced. In comparison with the 5'-UTR of tobacco mosaic virus (Omega sequence), a known translational enhancer, the NtADH 5'-UTR enhanced translation to a similar level. Meanwhile, the translational efficiency was affected by the sequence context around the AUG initiation codon at the translational initiation step. Moreover, this NtADH 5'-UTR also worked in stable tobacco transformants. Therefore, it is expected that this 5'-UTR will serve as a powerful tool for enhancing foreign gene expression.
 ...
PMID:The 5'-untranslated region of the tobacco alcohol dehydrogenase gene functions as an effective translational enhancer in plant. 1623 58

To improve expression levels of recombinant proteins in plants, a new leader sequence was designed. Several elements known to enhance gene translation and/or transcription were considered, including the CaMV 35S Inr site, a CT-rich motif often shared by highly expressed plant genes and a poly(CAA) region widespread in tobamovirus and plant leaders. The effect of the synthetic leader on gusA expression was evaluated in genetically modified tobacco plants by measuring the beta-glucuronidase activity and the mRNA level. When compared to the gusA leader of pBI121, the new sequence determined a 8.6-fold and a 12.5-fold increase of enzyme concentration taking into account the whole plant population or the above-average expressors, respectively. Since most pCAMBIA vectors harbour a very short 5'-UTR, identical to a fragment of the pBI121 leader, leader replacement with the sequence herein described is strongly suggested.
 ...
PMID:Improvement of the pBI121 plant expression vector by leader replacement with a sequence combining a poly(CAA) and a CT motif. 1723 82

The genomic upstream sequence of the rice tubulin gene OsTub6 has been cloned, sequenced and characterized. The 5'UTR sequence is interrupted by a 446 bp long leader intron. This feature is shared with two other rice beta-tubulin genes (OsTub4 and OsTub1) that, together with OsTub6, group in the same clade in the evolutionary phylogenetic tree of plant beta-tubulins. Similarly to OsTub4, the leader intron of OsTub6 is capable of sustaining intron mediated enhancement (IME) of gene expression, in transient expression assays. A general picture is drawn for three rice alpha-tubulin and two rice beta-tubulin genes in which the first intron of the coding sequence for the formers and the intron present in the 5'UTR for the latters, are important elements for controlling gene expression. We used OsTua2:GUS, OsTua3:GUS, OsTub4:GUS and OsTub6:GUS chimeric constructs to investigate the in vivo pattern of beta-glucuronidase (GUS) expression in transgenic rice plants. The influence of the regulatory introns on expression patterns was evaluated for two of them, OsTua2 and OsTub4. We have thus characterized distinct patterns of expression attributable to each tubulin isotype and we have shown that the presence of the regulatory intron can greatly influence both the amount and the actual site of expression. We propose the term Intron Dependent Spatial Expression (IDSE) to highlight this latter effect.
 ...
PMID:In trangenic rice, alpha- and beta-tubulin regulatory sequences control GUS amount and distribution through intron mediated enhancement and intron dependent spatial expression. 1866 37

The high-affinity phosphate transporter AtPht1;4 (Arabidopsis phosphate transporter1;4) is not only induced in response to inorganic phosphate (Pi) starvation but also preferentially expressed in the roots of Arabidopsis. In this study, we carried out AtPht1;4 promoter deletion analysis to identify regions that control the Pi responsiveness and spatiotemporal expression of the gene. Expression cassettes with truncated promoter fragments cloned to GUS (beta-glucuronidase) coding sequence were developed. Full-length promoter (-2327) and truncations up to -1436 (from the translational start) showed normal expression of GUS in various parts of the plants. The Pi responsiveness and inducibility of the reporter gene remained unaltered. However, deletion of the promoter region containing the first PHR1-binding site (P1BS) motif (-1350) abolished the AtPht1;4 expression in roots but not in aerial parts. A 164-bp region immediately upstream of the transcription start site appears to be sufficient for the basal expression of the gene. Interestingly, the 5'UTR (5' untranslated region) intron exhibited weak promoter activity as evidenced by its ability to drive the expression of AtPht1;4 in stipules and reproductive organs. Further analyses showed that the 5'UTR intron is essential for AtPht1;4 expression in root tips besides enhancing the level of expression in roots during Pi starvation. However, expression of AtPht1;4 in aerial parts of the plant was not influenced by the intron. Together these results suggest that expression of AtPht1;4 in the roots and aerial parts is regulated by independent mechanisms.
 ...
PMID:Promoter deletion analysis elucidates the role of cis elements and 5'UTR intron in spatiotemporal regulation of AtPht1;4 expression in Arabidopsis. 1950 64

The structure and function of untranslated mRNA leader sequences and their role in controlling gene expression remains poorly understood. Previous research has suggested that the 5' untranslated region (5'UTR) of the Vigna radiata aminocyclopropane-1-carboxylate synthase synthase (VR-ACS1) gene may function as a translational enhancer in plants. To test such hypothesis we compared the translation enhancing properties of three different 5'UTRs; those from the VR-ACS1, the chlorophyll a/b binding gene from petunia (Cab22L; a known translational enhancer) and the Vigna radiata pectinacetylesterase gene (PAE; used as control). Identical constructs in which the coding region of the beta-glucuronidase (GUS) gene was fused to each of the three 5'UTRs and placed under the control of the cauliflower mosaic virus 35S promoter were prepared. Transient expression assays in tobacco cell cultures and mung bean leaves showed that the VR-ACS1 and Cab22L 5'UTRs directed higher levels of GUS activity than the PAE 5'UTR. Analysis of transgenic Arabidopsis thaliana seedlings, as well as different tissues from mature plants, confirmed that while transcript levels were equivalent for all constructs, the 5'UTRs from the VR-ACS1 and Cab22L genes can increase GUS activity twofold to fivefold compared to the PAE 5'UTR, therefore confirming the translational enhancing properties of the VR-ACS1 5'UTR.
 ...
PMID:The 5' untranslated region of the VR-ACS1 mRNA acts as a strong translational enhancer in plants. 1981 82

Lack of regulated expression and tissue specificity are the major drawbacks of plant and virus-derived constitutive promoters. A precise tissue or site-specific expression, facilitate regulated expression of proteins at the targeted time and site. Publically available microarray data on whitefly and aphid infested Arabidopsis thaliana L. was used to identify whitefly and aphid-inducible genes. The qRT-PCR further validated the inducible behaviour of these genes under artificial infestation. Promoter sequences of genes were retrieved from the Arabidopsis Information Resources database with their corresponding 5'UTR and cloned from the A. thaliana genome. Promoter reporter transcriptional fusions were developed with the beta-glucuronidase (GUS) gusA gene in a binary expression vector to validate the inducible behaviour of these promoters in eight independent transgenic Nicotiana tabaccum lines. Histochemical analysis of the reporter gene in T2 transgenic tobacco lines confirmed promoter driven expression at the sites of aphid and whitefly infestation. The qRT-PCR and GUS expression analysis of transgenic lines revealed that abscisic acid largely influenced the expression of both aphid and whitefly inducible promoters. Further, whitefly-specific promoter respond to salicylic acid and jasmonic acid (JA), whereas aphid-specific promoters to JA and 1-aminocyclopropane carboxylic acid. The response of promoters to phytohormones correlated to the presence of corresponding conserved cis-regulatory elements.
 ...
PMID:Whitefly and aphid inducible promoters of Arabidopsis thaliana L. 2966 30


<< Previous 1 2