Occurrence of amitotic division of trophoblast cell nuclei in blastocysts of the western spotted skunk (Spilogale putorius latifrons).
Occurrence of amitotic division of trophoblast cell nuclei in blastocysts of the western spotted skunk (Spilogale putorius latifrons).
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西方斑点臭鼬 (Spilogale putorius latifrons) 囊胚中滋养层细胞核发生无丝分裂。
DOI：
10.1111/j.1601-5223.2004.01749.x
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
Mead,RodneyA
中科院分区：
文献类型：
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作者：
Isakova,GalinaK;Mead,RodneyA
对7只雌性西方斑点臭鼬滞育和早期激活囊胚的铺展细胞进行了细胞遗传学检查。从9个滞育囊胚中获得的1626个细胞中未观察到有丝分裂，而从5个早期激活胚胎中获得的851个细胞中观察到12个（1.5%）二倍体有丝分裂。细胞核直径在滞育期为4 ~ 29 μm，在激活期为5 ~ 40 μm，滞育期与激活期细胞核大小差异极显著（P<0.01）。约80%的滞育囊胚细胞核的大小为9 - 16 μm，而类似比例的激活囊胚细胞核的大小为15 - 27 μm。许多增大的细胞核表现出哺乳动物多线（即具有多线染色体组织的内多倍体）滋养层细胞的形态特征。银染核仁数不超过2个，与臭鼬二倍体核型中核仁组成者的数目一致，表明扩大的细胞核中染色体为多线结构。约10%的大间期核被观察到经历无丝分裂，即通过缢缩直接分裂。滞育囊胚中产生的核碎片通常具有正常形态和活性核仁。在激活的胚胎中，近15%的无丝分裂核分裂成大小不等的碎片，其中一个碎片具有正常的细胞核形态和非常大的银阳性核仁，另一个碎片则表现出细胞死亡的迹象。我们解释这些数据表明：1）在臭鼬囊胚滋养层内多倍体细胞核的无丝分裂可能会产生新的滋养层细胞，这有助于增加细胞数量在滞育和激活阶段，和2）滞育后的激活囊胚是与生产的滋养层细胞的合成能力增强。
A cytogenetic examination of spreaded cells of diapausing and early activated blastocysts obtained from 7 female western spotted skunks was performed. Mitosis was not observed in 1626 cells obtained from 9 diapausing blastocysts; however, 12 (1.5%) figures of diploid mitosis were seen in 851 cells from 5 early activated embryos. Diameter of the cell nuclei varied from 4 to 29 μm during diapause, and from 5 to 40 μm in activated blastocyst, and the heterogeneity in nuclear size was significantly different between diapausing and activated embryos (P<0.01). About 80% of nuclei from diapausing blastocysts measured 9 to16 μm, whereas a similar percentage of nuclei from activated blastocysts ranged from 15 to 27 μm. Many enlarged nuclei exhibited morphological features characteristic of mammalian polytene (i.e. endopolyploid with polytenic organization of chromosomes) trophoblast cells. The number of silver stained nucleoli in all the nuclei did not exceed 2, which corresponds to the number of nucleolus organizers in the diploid karyotype in this species of skunk and suggests the polytene organization of chromosomes in enlarged nuclei. About 10% of large interphase nuclei were observed to undergo amitosis,i.e. direct division by constriction. The resulting nuclear fragments in diapausing blastocysts usually had normal morphology and active nucleoli. In activated embryos, nearly 15% of amitotically divided nuclei appeared to be dividing into fragments of unequal size, one of which had normal cell nuclear morphology and extremely large silver positive nucleoli, and the other fragment exibited signs of cell death. We interpret these data as indicating that 1) amitotic division of trophoblast endopolyploid cell nuclei in the skunk blastocysts may generate new trophoblast cells which contribute to increased cell number during both diapause and activation stages, and 2) activation of blastocysts after diapause is related to the production of trophoblast cells with enhanced synthetic capabilities.