Submitted to: Weed Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/23/2005
Publication Date: 8/1/2005
Citation: Horvath, D.P., Anderson, J.V., Jia, Y., Chao, W.S. 2005. Cloning,characterization, and expression of growth regulator CYCLIN D3-2 in leafy spurge (Euphorbia esula). Weed Science. 53:431-437. Interpretive Summary: We have cloned a gene encoding cyclin D3-2, a key regulatory protein involved in controlling cell division from the perennial weed leafy spurge. This gene is up-regulated by conditions that induce growth and down-regulated by conditions that inhibit growth in the underground adventitious buds of this weed. A comparison of this gene to a similar gene from the model plant, Arabidopsis thaliana, identified several sequences in the promoter of the gene and in the untranslated but transcribed region of the gene that are likely to play a significant role in turning this gene on and off.
Technical Abstract: We have isolated a genomic and near full length cDNA clone for a D class cyclin gene from the perennial weed leafy spurge (Euphorbia esula). Sequence analysis indicates that this gene has the highest similarity to CYCLIN D3-2 of Arabidopsis. This gene is preferentially expressed in growing shoot apices, and is up-regulated in adventitious buds upon resumption of growth following loss of correlative inhibition. CYCLIN D3-2 is also induced in non-growing adventitious buds of plants treated with GA, or after removal of leaves- both treatments are known to initiate the G1 to S phase transition of the cell cycle in adventitious buds. CYCLIN D3-2 was not induced upon removal of the apical and axillary buds. Expression of CYCLIN D3-2 is down-regulated in adventitious crown buds during initiation of eco-dormancy in early winter. Sequence comparisons of CYCLIN D3-2 with its putative orthologue from Arabidopsis identified several conserved motifs in the promoter region, and two conserved regions capable of forming stable hairpin loops in the 5' untranslated region. Conservation of these non-coding sequences across species boundary strongly suggests they have a regulatory function.