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RSS1 regulates the cell cycle and maintains meristematic activity under stress conditions in rice.

Ogawa D, Abe K, Miyao A, Kojima M, Sakakibara H, Mizutani M, Morita H, Toda Y, Hobo T, Sato Y, Hattori T, Hirochika H, Takeda S - Nat Commun (2011)

Bottom Line: Here we show that a rice protein, RSS1, whose stability is controlled by cell cycle phases, contributes to the vigour of meristematic cells and viability under salinity conditions.These effects of RSS1 are exerted by regulating the G1-S transition, possibly through an interaction of RSS1 with protein phosphatase 1, and are mediated by the phytohormone, cytokinin.RSS1 is conserved widely in plant lineages, except eudicots, suggesting that RSS1-dependent mechanisms might have been adopted in specific lineages during the evolutionary radiation of angiosperms.

View Article: PubMed Central - PubMed

Affiliation: Bioscience and Biotechnology Center, Nagoya University, Chikusa, Nagoya 464-8601, Japan.

ABSTRACT
Plant growth and development are sustained by continuous cell division in the meristems, which is perturbed by various environmental stresses. For the maintenance of meristematic functions, it is essential that cell division be coordinated with cell differentiation. However, it is unknown how the proliferative activities of the meristems and the coordination between cell division and differentiation are maintained under stressful conditions. Here we show that a rice protein, RSS1, whose stability is controlled by cell cycle phases, contributes to the vigour of meristematic cells and viability under salinity conditions. These effects of RSS1 are exerted by regulating the G1-S transition, possibly through an interaction of RSS1 with protein phosphatase 1, and are mediated by the phytohormone, cytokinin. RSS1 is conserved widely in plant lineages, except eudicots, suggesting that RSS1-dependent mechanisms might have been adopted in specific lineages during the evolutionary radiation of angiosperms.

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RSS1 encodes an uncharacterized protein containing a D-box.(a) (top) The schematic structure of RSS1. Rectangles indicate the exons. The first ATG, the stop codon, and the insertion sites of the Tos17 retrotransposon (arrows) in the three mutant alleles are shown. (bottom) The RSS1 protein including its conserved motifs. The three regions containing amino acid (a.a.) sequences that are conserved among the RSS1 homologues, the DEN and double D-Box, the WAGE motif, and the C-terminal acidic amino-acid-rich region are shown. (b) Assay for the interaction of RSS1 with the subunits of APC/C by the yeast two-hybrid system. (top) The GAL4 DNA-binding domain fused to the truncated RSS1 (a.a. 1–207) and GAL4 activation domain fused to OsCdh1;1 (Os01g0972900), OsCdh1;2 (Os03g0123300) or OsCdc20;1 (Os04g0599800) were co-expressed in the yeast cells carrying the reporter genes, ADE2 and HIS3. The yeast cells were grown on the appropriate medium (which did not contain the indicated amino acids). (bottom) The two-hybrid assay using truncated RSS1 (a.a. 1–104) with or without the D-boxes as the bait. Empty indicates the vector control. (c, d) The cell cycle-dependent accumulation of GFP (c) and RSS1-GFP (d). Rice Oc cells carrying the respective transgenes were synchronized and used for ploidy analysis (top) and immunoblot analysis using anti-GFP (middle) at the indicated time points after release from G1 arrest by starvation. (top) The rates of 2C cells (blue) and 4C cells (magenta) are plotted. The 59-kDa band corresponds to the full-length RSS1-GFP protein. (bottom) Protein staining for the loading control of the immunoblot. (e) A simplified phylogeny of plants and the schematic structure of RSS1-related proteins representative of the respective lineages are illustrated. The percent amino-acid identity among sequences homologous to regions I and II is indicated. The C-terminal regions containing acidic amino acids are not necessarily homologous to region III. The dashed line indicates truncated sequence information. GenBank accession and code numbers are as follows: Arabidopsis AT3G14910 (NM_112353), Oryza sativa Os02g0606700 (RSS1) (NC_008395), Aristolochia fimbriata (FD758252), Nuphar advena (PUT-165a-Nuphar_advena-6361, Plant GDB (http://www.plantgdb.org/), Amborella trichopoda (CK757545), Picea sitchensis (ABK26784), Adiantum capillus-veneris (DK961685), and Syntrichia ruralis (CN201203).
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f2: RSS1 encodes an uncharacterized protein containing a D-box.(a) (top) The schematic structure of RSS1. Rectangles indicate the exons. The first ATG, the stop codon, and the insertion sites of the Tos17 retrotransposon (arrows) in the three mutant alleles are shown. (bottom) The RSS1 protein including its conserved motifs. The three regions containing amino acid (a.a.) sequences that are conserved among the RSS1 homologues, the DEN and double D-Box, the WAGE motif, and the C-terminal acidic amino-acid-rich region are shown. (b) Assay for the interaction of RSS1 with the subunits of APC/C by the yeast two-hybrid system. (top) The GAL4 DNA-binding domain fused to the truncated RSS1 (a.a. 1–207) and GAL4 activation domain fused to OsCdh1;1 (Os01g0972900), OsCdh1;2 (Os03g0123300) or OsCdc20;1 (Os04g0599800) were co-expressed in the yeast cells carrying the reporter genes, ADE2 and HIS3. The yeast cells were grown on the appropriate medium (which did not contain the indicated amino acids). (bottom) The two-hybrid assay using truncated RSS1 (a.a. 1–104) with or without the D-boxes as the bait. Empty indicates the vector control. (c, d) The cell cycle-dependent accumulation of GFP (c) and RSS1-GFP (d). Rice Oc cells carrying the respective transgenes were synchronized and used for ploidy analysis (top) and immunoblot analysis using anti-GFP (middle) at the indicated time points after release from G1 arrest by starvation. (top) The rates of 2C cells (blue) and 4C cells (magenta) are plotted. The 59-kDa band corresponds to the full-length RSS1-GFP protein. (bottom) Protein staining for the loading control of the immunoblot. (e) A simplified phylogeny of plants and the schematic structure of RSS1-related proteins representative of the respective lineages are illustrated. The percent amino-acid identity among sequences homologous to regions I and II is indicated. The C-terminal regions containing acidic amino acids are not necessarily homologous to region III. The dashed line indicates truncated sequence information. GenBank accession and code numbers are as follows: Arabidopsis AT3G14910 (NM_112353), Oryza sativa Os02g0606700 (RSS1) (NC_008395), Aristolochia fimbriata (FD758252), Nuphar advena (PUT-165a-Nuphar_advena-6361, Plant GDB (http://www.plantgdb.org/), Amborella trichopoda (CK757545), Picea sitchensis (ABK26784), Adiantum capillus-veneris (DK961685), and Syntrichia ruralis (CN201203).

Mentions: We molecularly identified RSS1 by transposon tagging and the subsequent isolation and characterization of two additional mutant alleles (Fig. 2a). Tos17 (4.1 kb) was inserted into the third exon of RSS1 in rss1-1 and rss1-2 and into the fourth intron in rss1-3. A full-length RSS1 cDNA driven by the rice actin or RSS1 promoter was able to complement the rss1 mutation (Supplementary Fig. S4). RSS1 encodes an uncharacterized protein consisting of 243 amino acids that was localized in both the nucleus and cytosol when fused to GFP (Supplementary Fig. S5). RSS1 showed no significant sequence similarity to any proteins with known function in the publicly accessible databases; however, it has a canonical motif, a 'destruction box' (D-box) and a D-box-like motif in its amino-terminal region (Supplementary Fig. S6). The D-box acts as a target signal for ubiquitin-26S proteasome-dependent degradation from prometaphase to the late G1 phase, which is regulated by the APC/C E3 ubiquitin ligase192021. This targeting is often specified in conjunction with another cis-sequence, or 'KEN-box'20. RSS1 also possesses a KEN-related sequence, the 'DEN-box,' and RSS1 was stabilized by treatment with a specific inhibitor of the 26S proteasome, MG132 (Supplementary Fig. S4). The N-terminal 104-amino-acid sequence containing both the D- and DEN-boxes was required and was sufficient for the 26S proteasome-dependent degradation. The deletion or amino-acid substitution of the D-boxes in RSS1 partially disrupted the effect of MG132. These results suggest that RSS1 is regulated by APC/C.


RSS1 regulates the cell cycle and maintains meristematic activity under stress conditions in rice.

Ogawa D, Abe K, Miyao A, Kojima M, Sakakibara H, Mizutani M, Morita H, Toda Y, Hobo T, Sato Y, Hattori T, Hirochika H, Takeda S - Nat Commun (2011)

RSS1 encodes an uncharacterized protein containing a D-box.(a) (top) The schematic structure of RSS1. Rectangles indicate the exons. The first ATG, the stop codon, and the insertion sites of the Tos17 retrotransposon (arrows) in the three mutant alleles are shown. (bottom) The RSS1 protein including its conserved motifs. The three regions containing amino acid (a.a.) sequences that are conserved among the RSS1 homologues, the DEN and double D-Box, the WAGE motif, and the C-terminal acidic amino-acid-rich region are shown. (b) Assay for the interaction of RSS1 with the subunits of APC/C by the yeast two-hybrid system. (top) The GAL4 DNA-binding domain fused to the truncated RSS1 (a.a. 1–207) and GAL4 activation domain fused to OsCdh1;1 (Os01g0972900), OsCdh1;2 (Os03g0123300) or OsCdc20;1 (Os04g0599800) were co-expressed in the yeast cells carrying the reporter genes, ADE2 and HIS3. The yeast cells were grown on the appropriate medium (which did not contain the indicated amino acids). (bottom) The two-hybrid assay using truncated RSS1 (a.a. 1–104) with or without the D-boxes as the bait. Empty indicates the vector control. (c, d) The cell cycle-dependent accumulation of GFP (c) and RSS1-GFP (d). Rice Oc cells carrying the respective transgenes were synchronized and used for ploidy analysis (top) and immunoblot analysis using anti-GFP (middle) at the indicated time points after release from G1 arrest by starvation. (top) The rates of 2C cells (blue) and 4C cells (magenta) are plotted. The 59-kDa band corresponds to the full-length RSS1-GFP protein. (bottom) Protein staining for the loading control of the immunoblot. (e) A simplified phylogeny of plants and the schematic structure of RSS1-related proteins representative of the respective lineages are illustrated. The percent amino-acid identity among sequences homologous to regions I and II is indicated. The C-terminal regions containing acidic amino acids are not necessarily homologous to region III. The dashed line indicates truncated sequence information. GenBank accession and code numbers are as follows: Arabidopsis AT3G14910 (NM_112353), Oryza sativa Os02g0606700 (RSS1) (NC_008395), Aristolochia fimbriata (FD758252), Nuphar advena (PUT-165a-Nuphar_advena-6361, Plant GDB (http://www.plantgdb.org/), Amborella trichopoda (CK757545), Picea sitchensis (ABK26784), Adiantum capillus-veneris (DK961685), and Syntrichia ruralis (CN201203).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3104554&req=5

f2: RSS1 encodes an uncharacterized protein containing a D-box.(a) (top) The schematic structure of RSS1. Rectangles indicate the exons. The first ATG, the stop codon, and the insertion sites of the Tos17 retrotransposon (arrows) in the three mutant alleles are shown. (bottom) The RSS1 protein including its conserved motifs. The three regions containing amino acid (a.a.) sequences that are conserved among the RSS1 homologues, the DEN and double D-Box, the WAGE motif, and the C-terminal acidic amino-acid-rich region are shown. (b) Assay for the interaction of RSS1 with the subunits of APC/C by the yeast two-hybrid system. (top) The GAL4 DNA-binding domain fused to the truncated RSS1 (a.a. 1–207) and GAL4 activation domain fused to OsCdh1;1 (Os01g0972900), OsCdh1;2 (Os03g0123300) or OsCdc20;1 (Os04g0599800) were co-expressed in the yeast cells carrying the reporter genes, ADE2 and HIS3. The yeast cells were grown on the appropriate medium (which did not contain the indicated amino acids). (bottom) The two-hybrid assay using truncated RSS1 (a.a. 1–104) with or without the D-boxes as the bait. Empty indicates the vector control. (c, d) The cell cycle-dependent accumulation of GFP (c) and RSS1-GFP (d). Rice Oc cells carrying the respective transgenes were synchronized and used for ploidy analysis (top) and immunoblot analysis using anti-GFP (middle) at the indicated time points after release from G1 arrest by starvation. (top) The rates of 2C cells (blue) and 4C cells (magenta) are plotted. The 59-kDa band corresponds to the full-length RSS1-GFP protein. (bottom) Protein staining for the loading control of the immunoblot. (e) A simplified phylogeny of plants and the schematic structure of RSS1-related proteins representative of the respective lineages are illustrated. The percent amino-acid identity among sequences homologous to regions I and II is indicated. The C-terminal regions containing acidic amino acids are not necessarily homologous to region III. The dashed line indicates truncated sequence information. GenBank accession and code numbers are as follows: Arabidopsis AT3G14910 (NM_112353), Oryza sativa Os02g0606700 (RSS1) (NC_008395), Aristolochia fimbriata (FD758252), Nuphar advena (PUT-165a-Nuphar_advena-6361, Plant GDB (http://www.plantgdb.org/), Amborella trichopoda (CK757545), Picea sitchensis (ABK26784), Adiantum capillus-veneris (DK961685), and Syntrichia ruralis (CN201203).
Mentions: We molecularly identified RSS1 by transposon tagging and the subsequent isolation and characterization of two additional mutant alleles (Fig. 2a). Tos17 (4.1 kb) was inserted into the third exon of RSS1 in rss1-1 and rss1-2 and into the fourth intron in rss1-3. A full-length RSS1 cDNA driven by the rice actin or RSS1 promoter was able to complement the rss1 mutation (Supplementary Fig. S4). RSS1 encodes an uncharacterized protein consisting of 243 amino acids that was localized in both the nucleus and cytosol when fused to GFP (Supplementary Fig. S5). RSS1 showed no significant sequence similarity to any proteins with known function in the publicly accessible databases; however, it has a canonical motif, a 'destruction box' (D-box) and a D-box-like motif in its amino-terminal region (Supplementary Fig. S6). The D-box acts as a target signal for ubiquitin-26S proteasome-dependent degradation from prometaphase to the late G1 phase, which is regulated by the APC/C E3 ubiquitin ligase192021. This targeting is often specified in conjunction with another cis-sequence, or 'KEN-box'20. RSS1 also possesses a KEN-related sequence, the 'DEN-box,' and RSS1 was stabilized by treatment with a specific inhibitor of the 26S proteasome, MG132 (Supplementary Fig. S4). The N-terminal 104-amino-acid sequence containing both the D- and DEN-boxes was required and was sufficient for the 26S proteasome-dependent degradation. The deletion or amino-acid substitution of the D-boxes in RSS1 partially disrupted the effect of MG132. These results suggest that RSS1 is regulated by APC/C.

Bottom Line: Here we show that a rice protein, RSS1, whose stability is controlled by cell cycle phases, contributes to the vigour of meristematic cells and viability under salinity conditions.These effects of RSS1 are exerted by regulating the G1-S transition, possibly through an interaction of RSS1 with protein phosphatase 1, and are mediated by the phytohormone, cytokinin.RSS1 is conserved widely in plant lineages, except eudicots, suggesting that RSS1-dependent mechanisms might have been adopted in specific lineages during the evolutionary radiation of angiosperms.

View Article: PubMed Central - PubMed

Affiliation: Bioscience and Biotechnology Center, Nagoya University, Chikusa, Nagoya 464-8601, Japan.

ABSTRACT
Plant growth and development are sustained by continuous cell division in the meristems, which is perturbed by various environmental stresses. For the maintenance of meristematic functions, it is essential that cell division be coordinated with cell differentiation. However, it is unknown how the proliferative activities of the meristems and the coordination between cell division and differentiation are maintained under stressful conditions. Here we show that a rice protein, RSS1, whose stability is controlled by cell cycle phases, contributes to the vigour of meristematic cells and viability under salinity conditions. These effects of RSS1 are exerted by regulating the G1-S transition, possibly through an interaction of RSS1 with protein phosphatase 1, and are mediated by the phytohormone, cytokinin. RSS1 is conserved widely in plant lineages, except eudicots, suggesting that RSS1-dependent mechanisms might have been adopted in specific lineages during the evolutionary radiation of angiosperms.

Show MeSH
Related in: MedlinePlus