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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 interacts with a catalytic subunit of PP1.(a) The interaction of RSS1 with OsPP1 by yeast two-hybrid systems. The GAL4 DNA-binding domain fused to the truncated RSS1 (a.a. 1–207) and the GAL4 activation domain fused to OsPP1 (Os03g0268000) were co-expressed in 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). Empty indicates the vector control. (b) An alignment of the amino-acid sequences of PP1 homologues (Arabidopsis thaliana TOPP4 (AT2G39840), Oryza sativa OsPP1, Homo sapiens PP1 (NP_002699.1), Oryctolagus cuniculus, PP1 (CAA43820), Saccharomyces cerevisiae GLC7 (NP_011059.1)). Black asterisks and blue diamonds indicate the residues that contribute to metal coordination and phosphate binding, respectively12. Red stars indicate the conserved residues involved in Rb binding16. (c) The bimolecular fluorescent complementation (BiFC) assay for interactions between RSS1 and OsPP1 in onion epidermal cells. The plasmids for expression of the indicated split YFP variants with the reference gene encoding mRFP were introduced by particle bombardment. Colour images for fluorescence of YFP (green, top) and mRFP (red, middle) are merged (bottom). Bars indicate 0.1 mm.
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f7: RSS1 interacts with a catalytic subunit of PP1.(a) The interaction of RSS1 with OsPP1 by yeast two-hybrid systems. The GAL4 DNA-binding domain fused to the truncated RSS1 (a.a. 1–207) and the GAL4 activation domain fused to OsPP1 (Os03g0268000) were co-expressed in 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). Empty indicates the vector control. (b) An alignment of the amino-acid sequences of PP1 homologues (Arabidopsis thaliana TOPP4 (AT2G39840), Oryza sativa OsPP1, Homo sapiens PP1 (NP_002699.1), Oryctolagus cuniculus, PP1 (CAA43820), Saccharomyces cerevisiae GLC7 (NP_011059.1)). Black asterisks and blue diamonds indicate the residues that contribute to metal coordination and phosphate binding, respectively12. Red stars indicate the conserved residues involved in Rb binding16. (c) The bimolecular fluorescent complementation (BiFC) assay for interactions between RSS1 and OsPP1 in onion epidermal cells. The plasmids for expression of the indicated split YFP variants with the reference gene encoding mRFP were introduced by particle bombardment. Colour images for fluorescence of YFP (green, top) and mRFP (red, middle) are merged (bottom). Bars indicate 0.1 mm.

Mentions: To gain further insight into the molecular function of RSS1, we searched for RSS1-interacting proteins by a yeast two-hybrid screen. Notably, we found that RSS1 binds to a catalytic subunit of PP1 (Fig. 7a,b). PP1 is a major serine/threonine protein phosphatase that regulates physiological processes in eukaryotes, including cellular signalling that leads to gene expression, cell cycle and cellular metabolism1213141516. We designated this RSS1-interacting PP1 OsPP1. Our data indicated that an N-terminal region of OsPP1 was sufficient for the interaction with RSS1 (Supplementary Fig. S14). When expressed in onion epidermal cells, OsPP1-fused GFP was localized both in the nucleus and in the cytosol, as was RSS1-GFP and YFP-RSS1 (Supplementary Fig. S5). The in vivo interaction between RSS1 and OsPP1 was confirmed by the bimolecular fluorescence complementation (BiFC) assay (Fig. 7c).


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 interacts with a catalytic subunit of PP1.(a) The interaction of RSS1 with OsPP1 by yeast two-hybrid systems. The GAL4 DNA-binding domain fused to the truncated RSS1 (a.a. 1–207) and the GAL4 activation domain fused to OsPP1 (Os03g0268000) were co-expressed in 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). Empty indicates the vector control. (b) An alignment of the amino-acid sequences of PP1 homologues (Arabidopsis thaliana TOPP4 (AT2G39840), Oryza sativa OsPP1, Homo sapiens PP1 (NP_002699.1), Oryctolagus cuniculus, PP1 (CAA43820), Saccharomyces cerevisiae GLC7 (NP_011059.1)). Black asterisks and blue diamonds indicate the residues that contribute to metal coordination and phosphate binding, respectively12. Red stars indicate the conserved residues involved in Rb binding16. (c) The bimolecular fluorescent complementation (BiFC) assay for interactions between RSS1 and OsPP1 in onion epidermal cells. The plasmids for expression of the indicated split YFP variants with the reference gene encoding mRFP were introduced by particle bombardment. Colour images for fluorescence of YFP (green, top) and mRFP (red, middle) are merged (bottom). Bars indicate 0.1 mm.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3104554&req=5

f7: RSS1 interacts with a catalytic subunit of PP1.(a) The interaction of RSS1 with OsPP1 by yeast two-hybrid systems. The GAL4 DNA-binding domain fused to the truncated RSS1 (a.a. 1–207) and the GAL4 activation domain fused to OsPP1 (Os03g0268000) were co-expressed in 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). Empty indicates the vector control. (b) An alignment of the amino-acid sequences of PP1 homologues (Arabidopsis thaliana TOPP4 (AT2G39840), Oryza sativa OsPP1, Homo sapiens PP1 (NP_002699.1), Oryctolagus cuniculus, PP1 (CAA43820), Saccharomyces cerevisiae GLC7 (NP_011059.1)). Black asterisks and blue diamonds indicate the residues that contribute to metal coordination and phosphate binding, respectively12. Red stars indicate the conserved residues involved in Rb binding16. (c) The bimolecular fluorescent complementation (BiFC) assay for interactions between RSS1 and OsPP1 in onion epidermal cells. The plasmids for expression of the indicated split YFP variants with the reference gene encoding mRFP were introduced by particle bombardment. Colour images for fluorescence of YFP (green, top) and mRFP (red, middle) are merged (bottom). Bars indicate 0.1 mm.
Mentions: To gain further insight into the molecular function of RSS1, we searched for RSS1-interacting proteins by a yeast two-hybrid screen. Notably, we found that RSS1 binds to a catalytic subunit of PP1 (Fig. 7a,b). PP1 is a major serine/threonine protein phosphatase that regulates physiological processes in eukaryotes, including cellular signalling that leads to gene expression, cell cycle and cellular metabolism1213141516. We designated this RSS1-interacting PP1 OsPP1. Our data indicated that an N-terminal region of OsPP1 was sufficient for the interaction with RSS1 (Supplementary Fig. S14). When expressed in onion epidermal cells, OsPP1-fused GFP was localized both in the nucleus and in the cytosol, as was RSS1-GFP and YFP-RSS1 (Supplementary Fig. S5). The in vivo interaction between RSS1 and OsPP1 was confirmed by the bimolecular fluorescence complementation (BiFC) assay (Fig. 7c).

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