title: Enucleation of demecolcine-treated bovine oocytes in cytochalasin-free medium: mechanism investigation and practical improvement.
abstract: Demecolcine-assisted/induced enucleation has been used in nuclear transfer cloning procedures for many species, yet its mechanism of action remains unclear. Primarily because oocytoplasm protrusion induced by demecolcine is inhibited by the presence of cytochalasin, its use has had limited application. In this experiment, we investigated the microtubule and microfilament alterations in bovine oocytes after demecolcine and/or cytochalasin B (CB) treatments by immunocytochemical staining. We also examined mechanical enucleation of demecolcine-treated oocytes in cytochalasin-free medium. The results showed that demecolcine-treatment disrupts the balance between microtubule/microfilament interactions primarily by deleting microtubules and with little effect on the microfilaments that we believe accounts for the membrane protrusion. The CB treatment reduced the amount of microfilaments but had little effect on the microtubules. Most demecolcine-induced membrane protrusions disappeared when exposed to CB. Western blotting showed that CB treatment increases G-actin, which indicates a decrease in the microfilaments. High oocyte enucleation, survival, and developmental rates occurred when demecolcine-assisted enucleation was carried out in a CB-free solution. Higher blastocyst development rates and blastocyst cell numbers were achieved compared to control, indicating that CB is not necessary in the enucleation procedure of bovine oocytes. This study provides a clearer understanding of the mechanism for the demecolcine-induced oocyte membrane protrusion, and substantiates the practical use of demecolcine-assisted enucleation in a CB-free environment.
authors: Department of Animal, Dairy and Veterinary Sciences, Utah State University, Logan, Utah 84321, USA. q.meng@aggiemail.usu.edu
authors: Qinggang
authors: Q
authors: Meng
authors: Xia
authors: X
authors: Wu
authors: Thomas D
authors: TD
authors: Bunch
authors: Kenneth
authors: K
authors: White
authors: Benjamin R
authors: BR
authors: Sessions
authors: Christopher J
authors: CJ
authors: Davies
authors: Lee
authors: L
authors: Rickords
authors: Guang-peng
authors: GP
authors: Li
mesh_terms: D008841:Actin Cytoskeleton; D000818:Animals; D002417:Cattle; D002462:Cell Membrane; D002467:Cell Nucleus; D002470:Cell Survival; D003571:Cytochalasin B / Q000737:chemistry / Q000494:pharmacology; D003703:Demecolcine / Q000737:chemistry* / Q000494:pharmacology; D005260:Female; D008870:Microtubules; D053652:Nuclear Transfer Techniques; D009865:Oocytes; D050257:Tubulin Modulators / Q000737:chemistry* / Q000494:pharmacology
chemical_list: D050257:Tubulin Modulators; D003571:Cytochalasin B; D003703:Demecolcine