Pattern and frequency of nondisjunction in oocytes from the Djungarian hamster are determined by the stage of first meiotic spindle inhibition

Détails

ID Serval
serval:BIB_2D3D37E5FE3F
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Pattern and frequency of nondisjunction in oocytes from the Djungarian hamster are determined by the stage of first meiotic spindle inhibition
Périodique
Chromosoma
Auteur⸱e⸱s
Hummler  E., Hansmann  I.
ISSN
0009-5915 (Print)
Statut éditorial
Publié
Date de publication
11/1988
Volume
97
Numéro
3
Pages
224-30
Notes
Journal Article
Research Support, Non-U.S. Gov't --- Old month value: Nov
Résumé
In order to study the mechanisms of nondisjunction at meiosis I in oocytes gonadotropin-stimulated Djungarian hamsters were treated at two stages [4.5 and 6 h post human chorionic gonadotropin (HCG)] during the preovulatory period with 1000 mg/kg Carbendazim (MBC). The compound, known to bind fast but reversibly to mammalian tubulin, was chosen to investigate whether the stage at which spindle function is inhibited affects the pattern of nondisjunction. Ovulated oocytes were cytologically prepared and scored for hyperhaploidy, diploidy and presegregation. Application at an early spindle phase, 4.5 h post HCG, to females stimulated with a low gonadotropin dose [3 IU pregnant mares serum (PMS); 2 IU HCG] caused a high frequency of nondisjunction (40.6%) with a more or less nonspecific pattern of malsegregated bivalents. Treatment at a late stage of spindle function (6 h post HCG) resulted in a less frequent (22.5%) but highly preferential malsegregation of those A-D group bivalents thought earlier to be late segregators. On the other hand, oocytes from females primed with a high (10 IU PMS and HCG) gonadotropin dose, a treatment assumed to delay meiosis by approximately 1.5 h, responded to MBC treatment at the late stage (6 h) with a nonspecific pattern and a high frequency (71.2%) of nondisjunction. The latter result is comparable to that in which MBC was given at the early stage (4.5 h) and after a low gonadotropin dose. The high nondisjunction response additionally indicates that spindles in hypergonadotropic stimulated oocytes are more susceptible and/or that the concentration of the inhibitor is higher in such oocytes. Only few oocytes with presegregation (3.1%; 0.0%; 1.7%) and few diploid oocytes (3.3%; 1.5%; 3.2%) with complete inhibition of meiosis I were observed. We conclude, that in Djungarian hamsters (1) the segregation of bivalents at meiosis I is asynchronous with the large A-D bivalents segregating last, (2) the phase in which spindle function is inhibited determines the pattern of nondisjunction, and (3) the resumption of meiosis I - from dictyotene to metaphase II - does not follow a rigidly timed programme but depends on the conditions of follicular maturation.
Mots-clé
Aneuploidy Animals Benzimidazoles/pharmacology *Carbamates Chorionic Gonadotropin/pharmacology Cricetinae Female Liver/cytology/embryology Meiosis Metaphase Mutagens/pharmacology *Nondisjunction, Genetic Oocytes/*cytology
Pubmed
Web of science
Création de la notice
24/01/2008 12:43
Dernière modification de la notice
20/08/2019 13:12
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