The cell cycle genes cycA1;1 and cdc2Os-3 are coordinately regulated by gibberellin in planta

Abstract

Internodal growth of deepwater rice (Oryza sativa L.) can achieve rates of up to 10 mm h(-1). In submergence-induced plants, gibberellic acid activates the cell division cycle first at the G1 --> S phase transition with a subsequent increase in mitotic activity. The proteins cycA1;1 and cdc2Os-3 are the regulatory and catalytic subunits, respectively, of cyclin-dependent protein kinases (CDKs) which are central to cell cycle regulation. Both genes are regulated by gibberellic acid in a coordinate manner with transcripts accumulating in the G2 phase prior to the B2-type mitotic cyclins described previously (M. Sauter et al. 1995, Plant J 7: 623-632), suggesting a distinct role in regulating G2/M phase progression. Since cdc2Os-3 belongs to a group of CDKs that have no counterparts in animals, it may function in a plant-specific gibberellin-regulated cell division process.

Transcriptome Analysis of Proliferating Arabidopsis Endosperm Reveals Biological Implications for the Control of Syncytial Division, Cytokinin Signaling, and Gene Expression Regulation

“…The other hormones, BL, MJ, and GA, play important roles in various aspects of plant development (del Pozo et al, 2005), and our silique/endosperm data would suggest a stronger influence of GA on transcription in the endosperm than of either BL and MJ (Table III; Supplemental Table S9). This is consistent with observations that jasmonic acid has a negative effect on G1/S and G2/M transitions (Świątek et al, 2002) and that GAs stimulate cell division (Fabian et al, 2000). However, the underrepresentation of BL-responsive genes was unexpected, since BLs have been shown to promote cell division and are able to up-regulate the expression of CYCD3;1 and CDKB1;1 (Yoshizumi et al, 1999;Hu et al, 2000).…”

Ethylene is a positive regulator for GA 3 -induced male sex in Anemia phyllitidis gametophytes

“…Activation of cells to division mediated by GA 3 through the activation of the G1/S phase transition of the cell cycle, was observed in gametophytes of A. phyllitidis during GA 3 -induced male sex expression (Kaźmierczak 2003) and in intercalary meristems of internodes of Oriza sativa steams (Fabian et al 2000). The induction of a celldivision cycle in O. sativa mediated by GA 3 was preceded by an increase in the expression of histone H3, growth replication factor (Os-GRF1) (van der Knaap et al 2000) and replication protein A1 (RPA) (van der Knaap 1997), GA 3 also activated the expression of cdc2Os-3 and cycA1;1 kinase and kinase dependent cyclin (Fabian at al. 2000).…”

Gibberellin Metabolism, Perception and Signaling Pathways in Arabidopsis

“…As described earlier, some of the GA biosynthetic genes GA3ox and GA20ox are down-regulated by GA, whereas GA2ox genes for deactivation of GA are up-regulated by GA. In addition, GA induces stem elongation by increasing transcription of several genes encoding proteins that are involved in cell elongation and division in rice and Arabidopsis, such as expansins (Cho and Kende, 1997), xyloglucan endotransglycosylases (Xu et al, 1996;Uozu et al, 2000) and cyclin-dependent protein kinases (Fabian et al, 2000).…”