Poster: Cell division

Abs # 666: Cloning, expression, and regulation of Cyclin D3 from leafy spurge

Presenter:	Horvath, David PP, horvathd@fargo.ars.usda.gov
Authors	Horvath, David PP (A)   Anderson, James V (A)
Affiliations:	(A): USDA-ARS/Red River Valley Agricultural Research Center

We have isolated genomic and a near full length cDNA clones for two cyclin D3 genes from the perennial weed leafy spurge (Euphorbia esula). Sequence analysis indicates that these genes have the highest similarity to cyclin D3-2 and cyclin D3-1 of Arabidopsis. Both genes are preferentially expressed in growing shoot apices, and are up-regulated in adventitious root buds upon resumption of growth following loss of correlative inhibition. Expression of cyclin D3-2 is initially induced and then inhibited in adventitious crown buds during initiation of endo-dormancy in autumn. Both genes are also induced in non-growing adventitious buds of plants treated with GA, or after removal of leaves- (both treatments known to initiate the G1 to S phase transition of the cell cycle in adventitious buds). Cyclin D3 genes were not induced upon removal of the apical and axillary buds. Sequence comparisons of these genes with their putative orthologues of Arabidopsis identified several conserved motifs in both the promoter and the 5' untranslated leader sequences. Reporter gene constructs designed to identify the function of these conserved elements are being prepared and the preliminary results of these studies will be presented.