title: The effect of the time interval between injection and parthenogenetic activation on the spindle formation and the in vitro developmental potential of somatic cell nuclear-transferred rat oocytes.
abstract: We examined the optimal conditions for somatic cell nuclear transfer (SCNT) in the rat. First, we examined the effect of preincubation time before activation on SCNT rat oocytes produced in the presence of MG132 with regard to spindle formation and the potential to develop into blastocysts. The spindles of SCNT oocytes continued to elongate with an increase in the culture duration and, in approximately half of oocytes, the chromosomes were distributed along the spindles at 120 min after incubation. Such abnormal spindle formation in SCNT oocytes is a possible reason for the low developmental potential of SCNT rat oocytes. To inhibit the formation of abnormal spindle formation, we examined secondly the developmental potential of rat SCNT oocytes that had been preincubated with nocodazole and demecolcine instead of MG132. The developmental rates in SCNT oocytes, however, were decreased. For successful rat somatic cell cloning, two steps might be required: (1) to culture the somatic cell nuclei for a sufficient time in MII oocyte cytoplasm to enhance nuclear reprogramming; and (2) to induce normal spindle formation with normal chromosomal construction.
authors.affiliation: Laboratory of Animal Reproduction, College of Agriculture, Kinki University, Nara, Japan.
authors.forename: Shigetoshi
authors.initials: S
authors.lastname: Mizumoto
authors.forename: Yoko
authors.initials: Y
authors.lastname: Kato
authors.forename: Yukio
authors.initials: Y
authors.lastname: Tsunoda
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D020090:Chromosome Segregation; D005260:Female; D007976:Leupeptins / Q000494:pharmacology; D053652:Nuclear Transfer Techniques; D009865:Oocytes / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D010312:Parthenogenesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D008941:Spindle Apparatus / Q000187:drug effects / Q000502:physiology*; D013997:Time Factors
chemical_list: D007976:Leupeptins; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde