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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effectiveness of loxP-Cre directed excision of a transgene was examined using phenotypic and molecular analyses. Two methods of combining the elements of this system, re-transformation and cross pollination, were found to produce different degrees of excision in the resulting plants. Two linked traits, beta-glucuronidase (GUS) and a gene encoding sulfonylurea-resistant acetolactate synthase (ALSr), were integrated into the genome of tobacco and Arabidopsis. The ALSr gene, bounded by loxP sites, was used as the selectable marker for transformation. The directed loss of the ALSr gene through Cre-mediated excision was demonstrated by the loss of resistance to sulfonylurea herbicides and by Southern blot analysis. The beta-glucuronidase gene remained active. The excision efficiency varied in F1 progeny of different lox and Cre parents and was correlated with the Cre parent. Many of the lox x Cre F1 progeny were chimeric and some F2 progeny retained resistance to sulfonylureas. Re-transformation of lox/ALS/lox/GUS tobacco plants with cre led to much higher efficiency of excision. Lines of tobacco transformants carrying the GUS gene but producing only sulfonylurea-sensitive progeny were obtained using both approaches for introducing cre. Similarly, Arabidopsis lines with GUS activity but no sulfonylurea resistance were generated using cross pollinations.
Mol Gen Genet 1992 Jul
PMID:Directed excision of a transgene from the plant genome. 149 84

A homologous transformation system was developed for the phytopathogenic fungus Claviceps purpurea. Orotidine-5'-monophosphate decarboxylase (OMPD)-deficient mutants were obtained by UV mutagenesis and selection for resistance against 5-fluoroorotate. These mutants could be complemented well by the corresponding genes of Aspergillus niger (pyrA) and Neurospora crassa (pyr4), yielding significantly higher transformation rates (and lower copy numbers per transformant) than the phleomycin resistance system. The homologous OMPD gene was isolated from a lambda genomic library by heterologous hybridization with the pyr4 gene of N. crassa, identified by complementation of Aspergillus and Claviceps mutants, and used to confirm homologous integration in Claviceps. The pyr transformation system also proved to be very efficient in cotransformation experiments using the bacterial beta-glucuronidase gene (uidA) as a reporter gene, which was also efficiently expressed during the parasitic cycle: honeydew produced by plants infected with pyr/uidA cotransformants was shown to contain significant levels of beta-glucuronidase activity.
Mol Gen Genet 1992 Aug
PMID:Efficient transformation of Claviceps purpurea using pyrimidine auxotrophic mutants: cloning of the OMP decarboxylase gene. 150 54

Different factors involved in the early steps of the T-DNA transfer process were studied by using a beta-glucuronidase gene (gusA) as a reporter in Nicotiana glauca leaf disc transformation experiments. The levels of transient expression of the gusA gene in leaf discs infected with several strains or vir mutants correlated well with their virulence phenotype, except for virC mutants. The rate of T-DNA transfer was shown to be stimulated in the case of non-oncogenic strains by the co-transfer of small amounts of oncogenic genes. It was found that the location of the T-DNA in the Agrobacterium genome affected the T-DNA transfer rate especially in virC mutants. The virC mutants transferred the gusA-containing T-DNA located on a binary vector more efficiently than the oncogenic T-DNA of the Ti plasmid. Although wild-type strains induced high levels of gusA expression early after infection, the gusA expression appeared to be lost late after infection in the infected leaf discs. In contrast, in leaf discs infected by virC mutants the level of gusA expression increased steadily in time. A model explaining these results is presented.
Plant Mol Biol 1992 Sep
PMID:Factors affecting the rate of T-DNA transfer from Agrobacterium tumefaciens to Nicotiana glauca plant cells. 151 Nov 27

A functional analysis of the promoter from the wheat alpha-amylase gene alpha-Amy2/54 is described. Mutant alpha-Amy2/54 promoters containing replacements or deletions were constructed and their ability to direct expression of the reporter gene beta-glucuronidase (GUS) in gibberellin-responsive oat aleurone protoplasts analysed. Chimaeric promoters using regions of the cauliflower mosaic virus (CaMV) 35S and alpha-Amy2/54 promoters were also analysed. The results suggest that at least three regions within the alpha-Amy2/54 promoter contain cis elements that are necessary for high-level gibberellin-regulated transcription. Fusion of 1.8 kb of promoter sequence upstream from -117 bp to a minimal (-55 CaMV 35S) promoter gave rise to hormone-independent expression implying that the region 3' to -117 bp contains an element which represses transcription in the absence of gibberellin or presence of abscisic acid.
Plant Mol Biol 1992 Sep
PMID:Localisation of cis elements in the promoter of a wheat alpha-Amy2 gene. 151 Nov 36

Stable transformation of Norway spruce tissue has been obtained following bombardment of mature somatic embryos with pRT99gus, a plasmid that contains neo coding for NPTII, and gusA, coding for beta-glucuronidase, both fused to the CaMV 35S promoter. At least 8 lines have been stably transformed (over 15 months in culture) following bombardment and selection on kanamycin. Polymerase chain reaction analyses showed a high frequency of cotransformation of the gusA and neo genes. The frequency of coexpression of the selected and unselected markers was 100%. DNA/DNA hybridization of one transformed line provided conclusive evidence of stable integration and showed copy numbers of over 10 plasmid sequences per genome. None of the transformed lines has remained embryogenic.
Plant Mol Biol 1992 Sep
PMID:Genetic transformation of Norway spruce (Picea abies (L.) Karst) using somatic embryo explants by microprojectile bombardment. 151 Nov 38

Many late embryogenesis abundant (Lea) protein genes in plants are regulated by abscisic acid (ABA). The RNA level of a carrot gene, DC8, increases in response to ABA in developing seeds. However, DC8 cannot be induced by ABA in adult tissues. We used chimeric genes made of various DC8 promoter fragments fused to beta-glucuronidase (GUS) to analyze the transcriptional regulation of DC8. DC8:GUS expression was measured in electroporated carrot protoplasts and in stably transformed carrots. The region of the DC8 promoter from -170 to -51 contained ABA-responsive sequences that required a 5' upstream region for high levels of expression in embryogenic callus protoplasts. 505 bp of the DC8 promoter conferred GUS expression in stably transformed somatic and zygotic embryos. DC8:GUS was expressed only in tissues formed in the seed. This includes cells in the embryo, the endosperm and the germinating seedlings. Gel retardation and competition experiments were performed to analyze the embryo nuclear protein-DNA binding activities in vitro. No binding activity was detected on the putative ABA-responsive region; however the 5' upstream regions located between -505 and -301 interacted with embryo nuclear factors. An additional site of DNA-protein interaction was located between positions -32 and +178. The nuclear proteins that bind these sequences were found in the embryo nuclei only, not in the nuclei from leaves or roots.
Plant Mol Biol 1992 Apr
PMID:Transcriptional regulation of a seed-specific carrot gene, DC8. 153 2

A genomic clone of an acyl carrier protein gene (Bcg4-4) which is highly expressed in developing embryos of Brassica rapa was isolated and sequenced. The promoter and transcription terminator regions of Bcg4-4 were used to express a beta-glucuronidase reporter gene in transgenic rapeseed. Deletion of repeated domains in the promoter region did not lower beta-glucuronidase expression in seeds.
Plant Mol Biol 1992 Feb
PMID:Non-essential repeats in the promoter region of a Brassica rapa acyl carrier protein gene expressed in developing embryos. 153 31

We have analysed the patterns of expression of a gene encoding beta-glucuronidase (GUS) fused to the promoter of the Agrobacterium tumefaciens T-DNA gene 5 during embryogenesis in carrot, Daucus carota L. Gene expression was monitored by a histochemical assay of beta-glucuronidase activity. The gene 5 promoter, although of bacterial origin, conferred expression upon the marker gene in all stages of embryo development. The patterns of expression however, differed between embryos in different stages of development. In the globular stage expression was confined to the basal part of the embryo, suggesting that the promoter is sensitive to regulatory functions active in the primary establishment of polarity in the radially symmetric globular embryo. In the heart and torpedo stages of development GUS expression was high in the entire embryonic axis, but not in the cotyledons. During germination expression was reduced in the elongating hypocotyl and radicle, and high levels of expression were detected only in the shoot and root apices. Among the transformed cell lines analysed, one was found that showed an aberrant pattern of GUS expression during embryogenesis, in that expression in the upper part of the embryo was undetectable, and expression was restricted to the root apex in later stages of development. This difference in organ specificity of expression is likely due to a large deletion of the promoter.
Plant Mol Biol 1992 Feb
PMID:Spatial and temporal expression patterns directed by the Agrobacterium tumefaciens T-DNA gene 5 promoter during somatic embryogenesis in carrot. 155 41

19-Nor synthetic progestins undergo extensive metabolism at the target cells. The resulting metabolic conversion products interact with putative steroid receptors within the cells, and through those interactions, they may exert either agonistic, synergistic and antagonistic hormonal effects. Studies conducted in our laboratories have disclosed that norethisterone (NET) and D-(1) norgestrel (LNG), two widely used contraceptive progestins, are biotransformed to several A-ring reduced (dihydro and tetrahydro) derivatives. The resulting metabolites 5 alpha-dihydro NET (5 alpha-NET) and 5 alpha-dihydro LNG bind with relative high affinity to the progesterone and androgen receptors. To gain insight into the underlying molecular events mediating the mode of action of NET and its neutral metabolites, we have examined the expression of their biological effects at target organs by using the rabbit uteroglobin gene model and the beta-glucuronidase activity of the mouse kidney. The results of a series of experiments seem to indicate that the enzyme-mediated formation of the 5 alpha (trans A/B ring junction) NET derivative results in a significant diminution of its progestational and androgenic potencies. Furthermore, 5 alpha-NET acquire a potent anti-progestational/contragestational effect as assessed in the female rabbit. These results demonstrated that 5 alpha-reduction of 19-nor progestins exerts a paradoxical effect, at least in terms of their hormone-like effects. The overall data are in line with the concept that metabolism of synthetic progestins at hormone-sensitive organs modulates their mechanisms of action.
J Steroid Biochem Mol Biol 1992 Mar
PMID:Mechanisms of hormonal and antihormonal action of contraceptive progestins at the molecular level. 156 19

Acyl carrier protein (ACP) is a key component of the fatty acid biosynthetic machinery in plants. A 1.4 kb 5' flanking region of a Brassica napus ACP gene (ACP05) was transcriptionally fused to the reporter gene beta-glucuronidase (GUS), and expression of the chimeric gene monitored in transgenic tobacco. GUS activity was found to increase through seed development reaching a maximum value, coincident with the most active phase of storage lipid synthesis that was, on average, 100-fold higher than that observed in leaf. In control plants transformed with CaMV 35S-GUS constructs, GUS activity was similar in leaf and all stages of seed development. Based on average values, the level of GUS expression obtained via the ACP promoter was comparable to that obtained from the CaMV 35S promoter. We therefore conclude that the isolated 5' ACP flanking sequence represents a strong promoter element involved in the developmental regulation of storage lipid synthesis in B. napus seed tissue. Putative regulatory elements in the 5' upstream region of ACP05 were identified by dot matrix analysis and by sequence comparison with the upstream regions from a second seed-expressed rape ACP gene and from an Arabidopsis ACP gene.
Plant Mol Biol 1992 Apr
PMID:The isolation and functional characterisation of a B. napus acyl carrier protein 5' flanking region involved in the regulation of seed storage lipid synthesis. 160 Jan 50


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