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RSS1 ensures cell division activity under stress conditions.

Annotated Information


'Figure 1. [1].

RSS1 ensures cell division activity under stress conditions[1].RSS1 affects SAM maintenance and abiotic stress responses[1].RSS1 contributes to maintenance of active cytokinin levels[1]. In the shoot, RSS1 contributes to the maintenance of the SAM.

we can see the size under stress conditions.See fig1[1]. In agreement with the proposed function of RSS1, genes involved in the cell cycle and DNA replication are preferentially downregulated in rss1 under high-salt conditions. Conspicuously, more than 30% of the genes that are expressed specifically in the shoot apex are coordinately downregulated in rss1 under high-salt conditions , supporting the proposed function of RSS1 in maintaining proliferative tissue activity[1]. RSS1 functions preferentially in dividing cells, and its stability is regulated by cell cycle phase-dependent protein degradation through the aphase-promoting complex/cyclosome (APC/C)26S proteasome pathway. Moreover, RSS1 interacts with a type 1 protein phosphatase (PP1), which regulates many cellular processes, including the cell division cycle[2][3][4][5][6]. What is more RSS1 acts as a key factor in the maintenance of meristematic activity by ensuring cell division under stressful environmental conditions[1].


'Figure 2. [1].

RSS1 mRNA is expressed abundantly in proliferating tissue, such as the basal region of the shoot, which contains apical and lateral shoot meristems and leaf primordia, and to a lesser extent, in the upper region of the shoot. RSS1 expression is upregulated by low temperatures, but not by high-salt conditions Supplementary[1].In the shoot apical meristem (SAM), RSS1 mRNA is detected only weakly in the central zone, where the cells are less active in terms of division and are completely undifferentiated[1].People have established the spatial pression of RSsl in rice and found it to be expressed predominantly in the seed endosperm.Temporal expression analysis revealed maximum expression of seed development at 3-5DAP[7].Look at Fig 2.

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[1].


'Figure 3. [1].

RSS1-related sequences are not only highly conserved among monocots, but can also be identified in basal angiosperms, including Amborella trichopoda, which belongs to the most ancient lineage of extant angiosperms (Fig.3)22. RSS1-related genes also exist in gymnosperms, ferns and mosses[1].Please see Fig3.

In addition to the N-terminal region containing the DEN-box and D-box/D-box-like motifs (region I), these RSS1 homologues have a well-conserved region in the middle region (region II), which includes a sequence (W–A–K/R–D/E/G–G–V/I–E) designated the ‘WAGE’ motif and a moderately conserved carboxyterminal acidic region (region III)and Supplementary . Notably, no proteins with overall similarity to RSS1 exist in eudicots, although sequences related to region I are found[1].

Knowledge Extension

Post embryonic growth of plants depends on cell division activity in the shoot and root meristems, in conjunction with subsequent cell differentiation. Under environmental stress conditions, where plant growth is moderately impaired, the meristematic activity is maintained by mechanisms as yet unknown. We previously showed that the rice protein RSS1, whose stability is regulated depending on the cell cycle phases, is a key factor for the maintenance of meristematic activity under stressful conditions. RSS1 interacts with a catalytic subunit of protein phosphatase 1 (PP1), but other molecular characteristics are largely unknown. Here we show that RSS1 interacts with all the PP1 expressed in the shoot apex of rice. This interaction requires one of the conserved regions of RSS1, which is important for RSS1 function. Interestingly, the recombinant RSS1 protein is highly resistant to heat with respect to its anti-coagulability and binding activity to PP1. The features of RSS1 are reminiscent of those of inhibitor-2 of animals, although it is likely that the mode of function of RSS1 is different from that of inhibitor-2. Noticeably, RSS1 binds to PP1 under extremely high ionic strength conditions in vitro. Therefore, RSS1 possibly functions by forming a stable complex with PP1.[8].

Labs working on this gene

1 Bioscience and Biotechnology Center, Nagoya University, Chikusa, Nagoya 464-8601, Japan

2 National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan

3 RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan.

4 Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya 464-8601, Japan. Correspondence and requests for material should be addressed to H.H. (hirohiko@nias.affrc.go.jp) or to S.T. (takeda@agr.nagoya-u.ac.jp).

5 Department of Nutritional Sciences, 231 Morgan Hall, University of Calfornia, Berkelev. CA 94720, USA.


  1. 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 Ogawa D, Abe K, Miyao A, et al. RSS1 regulates the cell cycle and maintains meristematic activity under stress conditions in rice[J]. Nature communications, 2011, 2: 278.
  2. Goldberg, J. et al. Three-dimensional structure of the catalytic subunit of protein serine/threonine phosphatase-1. Nature 376, 745–753 (1995).
  3. Berndt, N., Dohadwala, M. & Liu, C. W. Constitutively active protein phosphatase 1alpha causes Rb-dependent G1 arrest in human cancer cells. Curr. Biol. 7, 375–386 (1997).
  4. Cohen, P. T. Protein phosphatase 1—targeted in many directions. J. Cell Sci.115, 241–256 (2002).
  5. Ceulemans, H. & Bollen, M. Functional diversity of protein phosphatase-1,a cellular economizer and reset button. Physiol. Rev. 84, 1–39 (2004).
  6. Hirschi, A. et al. An overlapping kinase and phosphatase docking site regulates activity of the retinoblastoma protein. Nat. Struct. Mol. Biol. 17, 1051–1057 (2010).
  7. Odegard W, Liu J J, de Lumen B O. Cloning and expression of rice (< i> Oryza sativa</i>) sucrose synthase 1 (RSs1) in developing seed endosperm[J]. Plant Science, 1996, 113(1): 67-78
  8. Ogawa D, Morita H, Hattori T, et al. Molecular characterization of the rice protein RSS1 required for meristematic activity under stressful conditions[J]. Plant Physiology and Biochemistry, 2012, 61: 54-60.

Structured Information