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| Title: Differential distribution of proteins expressed in companion cells in the sieve element-companion cell complex of rice plants .
| | Author: Fukuda A Fujimaki S Mori T Suzui N Ishiyama K Hayakawa T Yamaya T Fujiwara T Yoneyama T Hayashi H | | Journal: Plant Cell Physiol .
Citation: V : 46 ( 11 ) P : 1779-86 Year: 2005 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub16120685 Accession (PMID): 16120685 | | Abstract: Sieve tubes are comprised of sieve elements , enucleated cells that are incapable of RNA and protein synthesis .
The proteins in sieve elements are supplied from the neighboring companion cells through plasmodesmata .
In rice plants , it was unclear whether or not all proteins produced in companion cells had the same distribution pattern in the sieve element-companion cell complex In this study , the distribution pattern of four proteins , beta-glucuronidase ( GUS ) , green fluorescent protein ( GFP ) , thioredoxin h ( TRXh ) and glutathione S-transferase ( GST ) were analyzed .
The foreign proteins GUS and GFP were expressed in transgenic rice plants under the control of the TRXh gene promoter ( PTRXh ) , a companion cell-specific promoter .
Analysis of leaf cross-sections of PTRXh-GUS and PTRXh-GFP plants indicated high accumulation of GUS and GFP , respectively , in companion cells rather than in sieve elements .
GUS and GFP were also detected in phloem sap collected from leaf sheaths of the transgenic rice plants , suggesting these proteins could enter sieve elements .
Relative amounts of GFP and endogenous phloem proteins , TRXh and GST , in phloem sap and total leaf extracts were compared .
Compared to TRXh and GST , GFP content was higher in total leaf extracts , but lower in phloem sap , suggesting that GFP accumulated mainly in companion cells rather than in sieve elements .
On the other hand , TRXh and GST appeared to accumulate in sieve elements rather than in companion cells .
These results indicate the evidence for differential distribution of proteins between sieve elements and companion cells in rice plants . | Matching Sentences:
[ Sen. 3, subscore: 1.00 ]: In rice plants , it was unclear whether or not all proteins produced in companion cells had the same distribution pattern in the sieve element-companion cell complex In this study , the distribution pattern of four proteins , beta-glucuronidase ( GUS ) , green fluorescent protein ( GFP ) , thioredoxin h ( TRXh ) and glutathione S-transferase ( GST ) were analyzed .
[ Sen. 4, subscore: 1.00 ]: The foreign proteins GUS and GFP were expressed in transgenic rice plants under the control of the TRXh gene promoter ( PTRXh ) , a companion cell-specific promoter .
[ Sen. 7, subscore: 1.00 ]: Relative amounts of GFP and endogenous phloem proteins , TRXh and GST , in phloem sap and total leaf extracts were compared .
[ Sen. 8, subscore: 1.00 ]: Compared to TRXh and GST , GFP content was higher in total leaf extracts , but lower in phloem sap , suggesting that GFP accumulated mainly in companion cells rather than in sieve elements .
[ Sen. 9, subscore: 1.00 ]: On the other hand , TRXh and GST appeared to accumulate in sieve elements rather than in companion cells .
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Score: 3.00 |
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| Title: A novel cis-element that is responsive to oxidative stress regulates three antioxidant defense genes in rice .
| | Author: Tsukamoto S Morita S Hirano E Yokoi H Masumura T Tanaka K | | Journal: Plant Physiol .
Citation: V : 137 ( 1 ) P : 317-27 Year: 2005 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub15618434 Accession (PMID): 15618434 | | Abstract: All organisms have defense systems against oxidative stress that include multiple genes of antioxidant defense .
These genes are induced by reactive oxygen species under condition of oxidative stress .
In this study , we found that a 28-bp motif is conserved on the promoter regions of three antioxidant defense genes in rice ( Oryza sativa ) : cytosolic superoxide dismutase ( sodCc1 ) , cytosolic thioredoxin ( trxh ) , and glutaredoxin ( grx ) .
We demonstrated that the 28-bp sequence acts as a cis-element responsive to oxidative stress by transient expression assay and designated it as CORE ( coordinate regulatory element for antioxidant defense ) .
The CORE was activated by methyl viologen treatment and induced a 3 . 1-fold increase in expression of the reporter gene , but it did not respond to hydrogen peroxide .
The expressions of the sodCc1 , trxh , and grx genes were coordinately induced by methyl viologen , suggesting that multiple genes involved in antioxidant defense are controlled by a common regulatory mechanism via CORE .
Application of the mitogen-activated protein kinase kinase inhibitor caused the constitutive induction of the sodCc1 , trxh , and grx genes and the activation of CORE without methyl viologen treatment .
These results indicate that a mitogen-activated protein kinase cascade is involved in the gene regulation mediated by CORE . | Matching Sentences:
[ Sen. 3, subscore: 1.00 ]: In this study , we found that a 28-bp motif is conserved on the promoter regions of three antioxidant defense genes in rice ( Oryza sativa ) : cytosolic superoxide dismutase ( sodCc1 ) , cytosolic thioredoxin ( trxh ) , and glutaredoxin ( grx ) .
[ Sen. 6, subscore: 1.00 ]: The expressions of the sodCc1 , trxh , and grx genes were coordinately induced by methyl viologen , suggesting that multiple genes involved in antioxidant defense are controlled by a common regulatory mechanism via CORE .
[ Sen. 7, subscore: 1.00 ]: Application of the mitogen-activated protein kinase kinase inhibitor caused the constitutive induction of the sodCc1 , trxh , and grx genes and the activation of CORE without methyl viologen treatment .
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Score: 1.00 |
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| Title: Identification , cloning and characterization of two thioredoxin h isoforms , HvTrxh1 and HvTrxh2 , from the barley seed proteome .
| | Author: Maeda K Finnie C Stergaard O Svensson B | | Journal: Eur .
J Biochem .
Citation: V : 270 ( 12 ) P : 2633-43 Year: 2003 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub12787030 Accession (PMID): 12787030 | | Abstract: Two thioredoxin h isoforms , HvTrxh1 and HvTrxh2 , were identified in two and one spots , respectively , in a proteome analysis of barley ( Hordeum vulgare ) seeds based on 2D gel electrophoresis and MS .
HvTrxh1 was observed in 2D gel patterns of endosperm , aleurone layer and embryo of mature barley seeds , and HvTrxh2 was present mainly in the embryo .
During germination , HvTrxh2 decreased in abundance and HvTrxh1 decreased in the aleurone layer and endosperm but remained at high levels in the embryo .
On the basis of MS identification of the two isoforms , expressed sequence tag sequences were identified , and cDNAs encoding HvTrxh1 and HvTrxh2 were cloned by RT-PCR .
The sequences were 51% identical , but showed higer similarity to thioredoxin h isoforms from other cereals , eg rice Trxh ( 74% identical with HvTrxh1 ) and wheat TrxTa ( 90% identical with HvTrxh2 ) .
Recombinant HvTrxh1 , HvTrxh2 and TrxTa were produced in Escherichia coli and purified using a three-step procedure .
The activity of the purified recombinant thioredoxin h isoforms was demonstrated using insulin and barley alpha-amylase/subtilisin inhibitor as substrates .
HvTrxh1 and HvTrxh2 were also efficiently reduced by Arabidopsis thaliana NADP-dependent thioredoxin reductase ( NTR ) .
The biochemical properties of HvTrxh2 and TrxTa were similar , whereas HvTrxh1 had higher insulin-reducing activity and was a better substrate for Arabidopsis NTR than HvTrxh2 , with a Km of 13 micro m compared with 44 micro m for HvTrxh2 .
Thus , barley seeds contain two distinct thioredoxin h isoforms which differ in temporal and spatial distribution and kinetic properties , suggesting that they may have different physiological roles .
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[ Sen. 5, subscore: 1.00 ]: The sequences were 51% identical , but showed higer similarity to thioredoxin h isoforms from other cereals , eg rice Trxh ( 74% identical with HvTrxh1 ) and wheat TrxTa ( 90% identical with HvTrxh2 ) .
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Score: 1.00 |
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| Title: Unique properties of NADP-thioredoxin reductase C in legumes .
| | Author: Alkhalfioui F Renard M Montrichard F | | Journal: Citation: V : ( ) P : Year: 2006 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub17185738 Accession (PMID): 17185738 | | Abstract: NADP-thioredoxin reductases ( NTRs ) reduce thioredoxins ( Trxs ) , using NADPH as a reductant , together constituting complete redox systems ( NTS ) .
Beside NTRA and NTRB targeted to both cytosol and mitochondria of plant cells , there is in chloroplasts an unusual NTR ( NTRC ) harbouring a Trx domain in a C-terminal extension , as recently reported in Oryza sativa .
Although NTRC may constitute a complete NTS , it was described as a bifunctional enzyme .
Because the gene is only present in photosynthetic organisms and the protein in green it issues , NTRC was thought to have a role restricted to photosynthetic cells .
To determine whether NTRC from dicot plants is a bifunctional enzyme or a complete NTS , as well as to identify its putative target , NTRC from Medicago truncatula was cloned and NTRA was cloned for comparison .
Here evidence is presented that MtNTRC ( i ) acts as an NTS and reduces dithiobisnitrobenzoate ( DTNB ) with a turnover ( 0 . 62 s ( -1 ) ) similar to that measured with MtNTRA in the presence of a Trxh ( 0 . 81 s ( -1 ) ) ; ( ii ) is able to use both NADPH ( k ( M ) =2 . 4 muM ) and NADH ( k ( M ) =11 muM ) as cofactors ; ( iii ) efficiently reduces BAS1 , a plastidial peroxiredoxin ; and ( iv ) is expressed in both leaves and stems but unexpectedly is even more abundant in cotyledons from dry and germinating seeds .
Because BAS1 is also present in both green it issues and seeds , NTRC/BAS1 may be involved in the scavenging of peroxides produced in green it issues during the day or the night and in seeds during germination .
These results suggest different roles for NTRC in monocot and dicot plants . | Matching Sentences:
[ Sen. 6, subscore: 1.00 ]: Here evidence is presented that MtNTRC ( i ) acts as an NTS and reduces dithiobisnitrobenzoate ( DTNB ) with a turnover ( 0 . 62 s ( -1 ) ) similar to that measured with MtNTRA in the presence of a Trxh ( 0 . 81 s ( -1 ) ) ; ( ii ) is able to use both NADPH ( k ( M ) =2 . 4 muM ) and NADH ( k ( M ) =11 muM ) as cofactors ; ( iii ) efficiently reduces BAS1 , a plastidial peroxiredoxin ; and ( iv ) is expressed in both leaves and stems but unexpectedly is even more abundant in cotyledons from dry and germinating seeds .
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