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11.
Molecular characterization of true and ectopic gene targeting events at the acetolactate synthase gene in Arabidopsis 总被引:3,自引:0,他引:3
Precise modification of plant genomes via gene targeting (GT) is important for the study of gene function in vivo. A reliable GT system using the protoporphyrinogen oxidase (PPO) gene in Arabidopsis was reported 4 years ago; however, there are no subsequent successful reports of GT in Arabidopsis. A previous study showed ectopic gene targeting (EGT) of the endogenous gene in two-thirds of GT plants, which was an obstacle to efficient true gene targeting (TGT). The endogenous acetolactate synthase (ALS) gene is involved in the biosynthesis of branched chain amino acids in plants and is the site of action of several herbicides. To confirm the generality of the GT system in Arabidopsis, and to characterize the EGT event in plants in detail, we converted ALS from a herbicide (imazapyr)-susceptible to a -resistant form by GT. We obtained two imazapyr-resistant plants following GT. One of the targeting events was TGT while the other was EGT. After detailed Southern blotting, PCR and nucleotide sequence analysis of the EGT plant, we determined the genomic position and structure of the ectopically targeted site. Based on our findings, we discuss the possible mechanisms of EGT in plants. 相似文献
12.
K Sato M Ishiai K Toda S Furukoshi A Osakabe H Tachiwana Y Takizawa W Kagawa H Kitao N Dohmae C Obuse H Kimura M Takata H Kurumizaka 《The EMBO journal》2012,31(17):3524-3536
Fanconi anaemia (FA) is a rare hereditary disorder characterized by genomic instability and cancer susceptibility. A key FA protein, FANCD2, is targeted to chromatin with its partner, FANCI, and plays a critical role in DNA crosslink repair. However, the molecular function of chromatin-bound FANCD2-FANCI is still poorly understood. In the present study, we found that FANCD2 possesses nucleosome-assembly activity in vitro. The mobility of histone H3 was reduced in FANCD2-knockdown cells following treatment with an interstrand DNA crosslinker, mitomycin C. Furthermore, cells harbouring FANCD2 mutations that were defective in nucleosome assembly displayed impaired survival upon cisplatin treatment. Although FANCI by itself lacked nucleosome-assembly activity, it significantly stimulated FANCD2-mediated nucleosome assembly. These observations suggest that FANCD2-FANCI may regulate chromatin dynamics during DNA repair. 相似文献
13.
Abiotic stress-inducible receptor-like kinases negatively control ABA signaling in Arabidopsis 总被引:1,自引:0,他引:1
Tanaka H Osakabe Y Katsura S Mizuno S Maruyama K Kusakabe K Mizoi J Shinozaki K Yamaguchi-Shinozaki K 《The Plant journal : for cell and molecular biology》2012,70(4):599-613
Membrane-anchored receptor-like protein kinases (RLKs) recognize extracellular signals at the cell surface and activate the downstream signaling pathway by phosphorylating specific target proteins. We analyzed a receptor-like cytosolic kinase (RLCK) gene, ARCK1, whose expression was induced by abiotic stress. ARCK1 belongs to the cysteine-rich repeat (CRR) RLK sub-family and encodes a cytosolic protein kinase. The arck1 mutant showed higher sensitivity than the wild-type to ABA and osmotic stress during the post-germinative growth phase. CRK36, an abiotic stress-inducible RLK belonging to the CRR RLK sub-family, was screened as a potential interacting factor with ARCK1 by co-expression analyses and a yeast two-hybrid system. CRK36 physically interacted with ARCK1 in plant cells, and the kinase domain of CRK36 phosphorylated ARCK1 in vitro. We generated CRK36 RNAi transgenic plants, and found that transgenic plants with suppressed CRK36 expression showed higher sensitivity than arck1-2 to ABA and osmotic stress during the post-germinative growth phase. Microarray analysis using CRK36 RNAi plants revealed that suppression of CRK36 up-regulates several ABA-responsive genes, such as LEA genes, oleosin, ABI4 and ABI5. These results suggest that CRK36 and ARCK1 form a complex and negatively control ABA and osmotic stress signal transduction. 相似文献
14.
Osakabe M Isobe H Kasai A Masuda R Kubota S Umeda M 《Experimental & applied acarology》2008,44(3):165-183
Aerial dispersal may be important for redistribution of spider mites into new habitats. Evidence for behavioral control of
aerial take-off has been well documented for Tetranychus urticae Koch. Before aerial dispersal they exhibit the aerial take-off posture that involves lifting the forelegs upright and raising
the forebody. However, whether the aerial take-off posture functions to increase drag has remained unclear. The objectives
of this study were to clarify: (i) aerodynamic effects of the aerial take-off posture; and (ii) actual aerial take-off behavior
in T. urticae. To evaluate the aerodynamic forces experienced by grounded spider mites in different postures, we constructed three-dimensional
models of T. urticae, exhibiting the aerial take-off posture and the normal posture, using computer graphics. We found that the aerial take-off
posture was effective in receiving greater rearward forces from wind rather than upward forces. As a result, aerial take-off
from a horizontal platform is unlikely. Instead, inverted departure surfaces, e.g., lower leaf surfaces, with inclines are
likely to be effective sites for take-off. Laboratory experiments and field observations indicated that the mites preferentially
adopted such a position for orientation and take-off. Our findings provided a rationale for the take-off behavior of Tetranychus spider mites. 相似文献
15.
Five non-allelic histone H3 variants, H3.1, H3.2, H3.3, H3t and CENP-A, have been identified in mammals. H3t is robustly expressed in the testis, and thus was assigned as the testis-specific H3 variant. However, recent proteomics and tissue-specific RT-PCR experiments revealed a small amount of H3t expression in somatic cells. In the present study, we purified human H3t as a recombinant protein, and showed that H3t/H4 forms nucleosomes with H2A/H2B by the salt-dialysis method, like the conventional H3.1/H4. We found that H3t/H4 is not efficiently incorporated into the nucleosome by human Nap1 (hNap1), due to its defective H3t/H4 deposition on DNA. In contrast, human Nap2 (hNap2), a paralog of hNap1, promotes nucleosome assembly with H3t/H4. Mutational analyses revealed that the Ala111 residue, which is conserved among H3.1, H3.2 and H3.3, but not in H3t, is the essential residue for the hNap1-mediated nucleosome assembly. These results suggest that H3t may be incorporated into chromatin by a specific chaperone-mediated pathway. 相似文献
16.
Comparative studies of the ecological and genetic traits of Panonychus citri (McGregor) populations on citrus and other host
plants were conducted. Panonychus citri on Osmanthus trees has a unique esterase allele and host range in comparison with
populations on other host plants, for example Citrus unshiu and Ilex crenata. Reproductive incompatibility between P. citri
populations on C. unshiu and Osmanthus fragrans was found. Therefore, in Japan, P. citri differentiates into two groups one
of which associates with Osmanthus, and the other with other host plants.
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
17.
18.
We isolated the 5′ flanking region of a gene for phenylalanine ammonia-lyase (PAL; EC 4.3.1.5) from Pinus taeda, PtaPAL. To investigate the tissue-specific expression of the PtaPAL promoter, histochemical assay of GUS activity was performed using the transgenic tobacco expressing the PtaPAL promoter-GUS. The region of −897 to −420 in PtaPAL promoter showed high activities in the secondary xylem and response to bending stress. To characterize the cis-regulatory functions of the promoters for enzymes in phenylpropanoid biosynthesis, we examined the activity of chimeric promoters
of PtaPAL and a 4-coumarate CoA ligase, Pta4CLα. The chimeric promoter showed similar activity as the Pta4CLα promoter. Electrophoretic mobility shift assays implicated −897 to –674 of PtaPAL promoter containing cis-elements of the expression in xylem of Pinus taeda. The results suggested that AC elements of PtaPAL have multiple functions in the expression under the various developmental stages and stress conditions in the transgenic
tobacco.
The nucleotide sequence data reported will appear in the EMBL, GenBank, and DDBJ Nucleotide Sequence Databases under the accession
number AB449103 (PtaPAL promoter sequence). 相似文献
19.
20.
The adaxial (upper) and abaxial (lower) surfaces of a plant leaf provide heterogeneous habitats for small arthropods with
different environmental conditions, such as light, humidity, and surface morphology. As for plant mites, some agricultural
pest species and their natural enemies have been observed to favor the abaxial leaf surface, which is considered an adaptation
to avoid rain or solar ultraviolet radiation. However, whether such a preference for the leaf underside is a common behavioral
trait in mites on wild vegetation remains unknown. The authors conducted a 2-year survey on the foliar mite assemblage found
on Viburnum erosum var. punctatum, a deciduous shrub on which several mite taxa occur throughout the seasons, and 14 sympatric tree or shrub species in secondary
broadleaf-forest sites in Kyoto, west–central Japan. We compared adaxial–abaxial surface distributions of mites among mite
taxa, seasons, and morphology of host leaves (presence/absence of hairs and domatia). On V. erosum var. punctatum, seven of 11 distinguished mite taxa were significantly distributed in favor of abaxial leaf surfaces and the trend was seasonally
stable, except for Eriophyoidea. Mite assemblages on 15 plant species were significantly biased towards the abaxial leaf surfaces,
regardless of surface morphology. Our data suggest that many mite taxa commonly prefer to stay on abaxial leaf surfaces in
wild vegetation. Oribatida displayed a relatively neutral distribution, and in Tenuipalpidae, the ratio of eggs collected
from the adaxial versus the abaxial side was significantly higher than the ratio of the motile individuals, implying that
some mite taxa exploit adaxial leaf surfaces as habitat. 相似文献