Poster: Cell Cycle & Cytokinesis

Abs # 1092: Expression of cell cycle genes in dormant and non-dormant underground adventitious buds of leafy spurge (Euphorbia esula L.)

Presenter:	Chao, Wun S., chaow@fargo.ars.usda.gov
Authors	Chao, Wun S. (A)   Anderson, James V. (A)   Horvath, David P. (A)
Affiliations:	(A): USDA, Agricultural Research Service

Leafy spurge (Euphorbia esula L.) is a deep rooted perennial weed that propagates vegetatively from an abundance of underground adventitious buds (UABs) located on the roots and crown and is the primary characteristic leading to its invasive nature. These buds develop during the normal growing season but are maintained in a quiescent state through correlative inhibition. Existing evidence indicates that growth-arrest is due to blockage of cell division resulting from interactions between the signaling pathways controlling dormancy and those controlling the cell cycle. We have cloned leafy spurge cell cycle genes encoding CDK-activating kinase (CAK), retinoblastoma (Rb), cullin, and an unknown growth-related protein (Up Regulated in Growth 1, URG1). Antibodies for these proteins were generated from maltose-binding-protein (MBP) fusion chimera, and affinity-purified using glutathione-S-transferase (GST) fusion chimera of the same proteins. We have examined the expression of these cell cycle genes using RT-PCR, RNA and protein blot analysis, immunoprecipitation, and phosphorylation in dormant and non-dormant UABs of leafy spurge. Current data indicates that CAK, Rb, and cullin are expressed constitutively at both transcriptional and translational levels, whereas the URG1 transcript is highly expressed in growing buds and meristem. The details of these results will be reported.