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| Title: Structure , expression , and functional analysis of the hexokinase gene family in rice ( Oryza sativa L ) .
| | Author: Cho JI Ryoo N Ko S Lee SK Lee J Jung KH Lee YH Bhoo SH Winderickx J An G Hahn TR Jeon JS .
| | Journal: Planta Citation: V : 224 ( 3 ) P : 598-611 Year: 2006 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub16552590 Accession (PMID): 16552590 | | Abstract: Hexokinase ( HXK ) is a dual-function enzyme that both phosphorylates hexose to form hexose 6-phosphate and plays an important role in sugar sensing and signaling .
To investigate the roles of hexokinases in rice growth and development , we analyzed rice sequence databases and isolated ten rice hexokinase cDNAs , OsHXK1 ( Oryza sativa Hexokinase 1 ) through OsHXK10 .
With the exception of the single-exon gene OsHXK1 , the OsHXKs all have a highly conserved genomic structure consisting of nine exons and eight introns .
Gene expression profiling revealed that OsHXK2 through OsHXK9 are expressed ubiquitously in various organs , whereas OsHXK10 expression is pollen-specific .
Sugars induced the expression of three OsHXKs , OsHXK2 , OsHXK5 , and OsHXK6 , in excised leaves , while suppressing OsHXK7 expression in excised leaves and immature seeds .
The hexokinase activity of the OsHXKs was confirmed by functional complementation of the hexokinase-deficient yeast strain YSH7 . 4-3C ( hxk1 , hxk2 , glk1 ) .
OsHXK4 was able to complement this mutant only after the chloroplast-transit peptide was removed .
The subcellular localization of OsHXK4 and OsHXK7 , observed with green fluorescent protein ( GFP ) fusion constructs , indicated that OsHXK4 is a plastid-stroma-targeted hexokinase while OsHXK7 localizes to the cytosol . | Matching Sentences:
[ Sen. 6, subscore: 1.00 ]: The hexokinase activity of the OsHXKs was confirmed by functional complementation of the hexokinase-deficient yeast strain YSH7 . 4-3C ( hxk1 , hxk2 , glk1 ) .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
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| Title: Evidence for a role of hexokinases as conserved glucose sensors in both monocot and dicot plant species .
| | Author: Cho JI Ryoo N Hahn TR Jeon JS | | Journal: Plant Signal Behav Citation: V : 4 P : Year: 2009 Type: Publisher | | Literature: oryza Field: abstract Doc ID: pub19826213 Accession (PMID): 19826213 | | Abstract: The role of the hexokinases ( HXKs ) as glucose ( Glc ) sensors has been mainly demonstrated for Arabidopsis ( Arabidopsis thaliana ) HXK1 ( AtHXK1 ) but has yet to be shown in other plant species .
In our recent publication , we reported that two rice ( Oryza sativa ) HXKs , OsHXK5 and OsHXK6 , also function as Glc sensors .
These two enzymes harbor both mitochondrial targeting peptides ( mTPs ) and nuclear localization signals ( NLSs ) , and we confirmed their dual-targeting ability to nuclei and mitochondria using GFP fusion experiments .
Consistently , it has been previously known that AtHXK1 is predominantly associated with mitochondria but is also present in nuclei in vivo at appreciable levels .
Notably , the expression of OsHXK5 , OsHXK6 , or their catalytically inactive mutant alleles complemented the Arabidopsis glucose insensitive2 ( gin2 ) mutant .
In addition , transgenic rice plants overexpressing OsHXK5 or OsHXK6 exhibited hypersensitive plant growth retardation and enhanced repression of the Rubisco small subunit ( RbcS ) gene in response to glucose treatment .
Our results thus provided evidence that OsHXK5 and OsHXK6 can function as glucose sensors in rice .
Hence , the available current data suggest that the role of the HXKs as Glc sensors may be conserved in both monocot and dicot plant species , and that the nuclear localization of AtHXK1 , OsHXK5 and OsHXK6 may be critical for Glc sensing and signaling .
| Matching Sentences:
[ Sen. 1, subscore: 1.00 ]: The role of the hexokinases ( HXKs ) as glucose ( Glc ) sensors has been mainly demonstrated for Arabidopsis ( Arabidopsis thaliana ) HXK1 ( AtHXK1 ) but has yet to be shown in other plant species .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 1.00 |
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| Title: Evidence for a role of hexokinases as conserved glucose sensors in both monocot and dicot plant species .
| | Author: Cho JI Ryoo N Hahn TR Jeon JS | | Journal: Plant Signal Behav Citation: V : 4 P : 908-10 Year: 2009 Type: In-Process | | Literature: oryza Field: abstract Doc ID: pub19938377 Accession (PMID): 19938377 | | Abstract: The role of the hexokinases ( HXKs ) as glucose ( Glc ) sensors has been mainly demonstrated for Arabidopsis ( Arabidopsis thaliana ) HXK1 ( AtHXK1 ) but has yet to be shown in other plant species .
In our recent publication , we reported that two rice ( Oryza sativa ) HXKs , OsHXK5 and OsHXK6 , also function as Glc sensors .
These two enzymes harbor both mitochondrial targeting peptides ( mTPs ) and nuclear localization signals ( NLSs ) , and we confirmed their dual-targeting ability to nuclei and mitochondria using GFP fusion experiments .
Consistently , it has been previously known that AtHXK1 is predominantly associated with mitochondria but is also present in nuclei in vivo at appreciable levels .
Notably , the expression of OsHXK5 , OsHXK6 , or their catalytically inactive mutant alleles complemented the Arabidopsis glucose insensitive2 ( gin2 ) mutant .
In addition , transgenic rice plants overexpressing OsHXK5 or OsHXK6 exhibited hypersensitive plant growth retardation and enhanced repression of the Rubisco small subunit ( RbcS ) gene in response to glucose treatment .
Our results thus provided evidence that OsHXK5 and OsHXK6 can function as glucose sensors in rice .
Hence , the available current data suggest that the role of the HXKs as Glc sensors may be conserved in both monocot and dicot plant species , and that the nuclear localization of AtHXK1 , OsHXK5 and OsHXK6 may be critical for Glc sensing and signaling .
| Matching Sentences:
[ Sen. 1, subscore: 1.00 ]: The role of the hexokinases ( HXKs ) as glucose ( Glc ) sensors has been mainly demonstrated for Arabidopsis ( Arabidopsis thaliana ) HXK1 ( AtHXK1 ) but has yet to be shown in other plant species .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
