Os03g03150

Function

Tillering and Dwarf 1 (TAD1) encodes a co-activator of the anaphase-promoting complex (APC/C), a multi-subunit E3 ligase. It shows increased tillers and reduced plant height. TAD1 encodes a Cdh1-type activator of APC/C, an ortholog to CCS52A in dicots. During the cell-cycle progression, TAD1 shows an oscillating expression pattern with a higher level in the G1-phase. TAD1 interacts with MOC1, forming a complex with OsAPC10 and functions as a co-activator of APC/C to target MOC1 for degradation in a cell-cycle-dependent manner. TAD1 encodes a Cdh1-type activator of APC/C, an ortholog to CCS52A in dicots.

Mutation

The tad1 mutant showed an increased tiller number, a reduced plant height, and twisted leaves and panicles.

Sequence analysis revealed a single base substitute (TGG→TGA) at the second exon of LOC_Os03g03150 in tad1, which produces a premature stop codon.

LOC_Os03g03150 is the TAD1 gene and the premature mutation is responsible for the phenotypes of the tad1 mutant plant. Sequence analysis revealed that TAD1 encodes a putative cell-cycle switch protein, belonging to a Cdh1 group of APC/C co-activators, which include fission yeast SRW1/STE9, budding yeast CDH1/HCT1, Drosophila FZR1, Medicago MtCCS52A10, Arabidopsis AtCCS52A, and mouse and human Cdh1. TAD1 is involved in regulating the exit of mitosis and it is indeed a functional cell-cycle switch protein homolo¬gous to Cdh1.

Expression

TAD1 is expressed ubiquitously in the examined rice organs, includ¬ing roots, shoot apices, axillary buds, internodes, nodes, and young leaves and panicles, but more abundant in young leaves, axillary buds and nodes. TAD1 was predominantly expressed in the leaf primordia and young leaves, tiller buds, inflorescence pro¬mordia, and crown root promordia. In addition, TAD1 expression was detected in vascular bundles at the unenlon¬gated stem. TAD1 has an oscillated expression pattern during the cell-cycle pro¬gression, showing a higher level in the G1-phase and a lower level in the S- and G2/M-phases. TAD1 most likely controls rice tillering through regulating MOC1. The 67-amino-acid N-terminal of TAD1 appears to be essential for its interaction with MOC1. TAD1 degrades MOC1 at the G1-phase. TAD1 recruits MOC1 to APC/C, and OsAPC10 is also involved in recognizing and target¬ing MOC1 for further degradation .

Evolution

The gene provides the identification and in-depth functional characterization of a specific component of the cell-cycle machinery in higher plants that regulates agronomically important traits, tillering and plant height to facili¬tate the genetic manipulation of plant architecture and the breeding of new varieties in agriculture in the future.

Labs working on this gene

1、State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China. 2、State Key Laboratory of Rice Biology, China National Rice Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310006, China.

References

1.Cebolla, A. et al. The mitotic inhibitor ccs52 is required for endoreduplication and ploidy-dependent cell enlargement in plants. EMBO J. 18, 4476–4484 (1999). 2.Vinardell, J. M. et al. Endoreduplication mediated by the anaphase-promoting complex activator CCS52A is required for symbiotic cell differentiation in Medicago truncatula nodules. Plant Cell 15, 2093–2105 (2003). 3. Kitamura, K., Maekawa, H. & Shimoda, C. Fission yeast Ste9, a homolog of Hct1/Cdh1 and Fizzy-related, is a novel negative regulator of cell cycle progression during G1-phase. Mol. Biol. Cell 9, 1065–1080 (1998). 4. Yamaguchi, S., Murakami, H. & Okayama, H. A WD repeat protein controls the cell cycle and differentiation by negatively regulating Cdc2/B-type cyclin complexes. Mol. Biol. Cell 8, 2475–2486 (1997). 5. Visintin, R., Prinz, S. & Amon, A. CDC20 and CDH1: a family of substrate-specific activators of APC-dependent proteolysis. Science 278, 460–463 (1997). 6. Schwab, M., Lutum, A. S. & Seufert, W. Yeast Hct1 is a regulator of Clb2 cyclin proteolysis. Cell 90, 683–693 (1997). 7. Sigrist, S. J. & Lehner, C. F. Drosophila fizzy-related down-regulates mitotic cyclins and is required for cell proliferation arrest and entry into endocycles. Cell 90, 671–681 (1997). 8. Li, M. et al. The adaptor protein of the anaphase promoting complex Cdh1 is essential in maintaining replicative lifespan and in learning and memory. Nat. Cell Biol. 10, 1083–1089 (2008). 9. Song, M. S. et al. Nuclear PTEN regulates the APC-CDH1 tumor-suppressive complex in a phosphatase-independent manner. Cell 144, 187–199 (2011). 10. Cebolla, A. et al. The mitotic inhibitor ccs52 is required for endoreduplication and ploidy-dependent cell enlargement in plants. EMBO J. 18, 4476–4484 (1999). 11. Vinardell, J. M. et al. Endoreduplication mediated by the anaphase-promoting complex activator CCS52A is required for symbiotic cell differentiation in Medicago truncatula nodules. Plant Cell 15, 2093–2105 (2003).

 12. Lammens, T. et al. Atypical E2F activity restrains APC/CCCS52A2 function obligatory for endocycle onset. Proc. Natl Acad. Sci. USA 105, 14721–14726 (2008).

13. Larson-Rabin, Z., Li, Z., Masson, P. H. & Day, C. D. FZR2/CCS52A1 expression is a determinant of endoreduplication and cell expansion in Arabidopsis. Plant Physiol. 149, 874–884 (2009). 14. Vanstraelen, M. et al. APC/CCCS52A complexes control meristem maintenance in the Arabidopsis root. Proc. Natl Acad. Sci. USA 106, 11806–11811 (2009). 15. Mathieu-Rivet, E. et al. Functional analysis of the anaphase promoting complex activator CCS52A highlights the crucial role of endo-reduplication for fruit growth in tomato. Plant J. 62, 727–741 (2010). 16. Boudolf, V. et al. CDKB1;1 forms a functional complex with CYCA2;3 to suppress endocycle onset. Plant Physiol. 150, 1482–1493 (2009). 17. Heyman, J. et al. Arabidopsis ULTRAVIOLET-B-INSENSITIVE4 maintains cell division activity by temporal inhibition of the anaphase-promoting complex/cyclosome. Plant Cell 23, 4394–4410 (2011). 18. Iwata, E. et al. GIGAS CELL1, a novel negative regulator of the anaphase-promoting complex/cyclosome, is required for proper mitotic progression and cell fate determination in Arabidopsis. Plant Cell 23, 4382–4393 (2011). 19. Blilou, I. et al. The Arabidopsis HOBBIT gene encodes a CDC27 homolog that links the plant cell cycle to progression of cell differentiation. Genes Dev. 16, 2566–2575 (2002). 20. Capron, A. et al. The Arabidopsis anaphase-promoting complex or cyclosome: molecular and genetic characterization of the APC2 subunit. Plant Cell 15, 2370–2382 (2003). 21. Kwee, H. S. & Sundaresan, V. The NOMEGA gene required for female gametophyte development encodes the putative APC6/CDC16 component of the anaphase promoting complex in Arabidopsis. Plant J. 36, 853–866 (2003).