STUDY OF X-CHROMOSOME REGULATION DURING OOGENESIS IN MOUSE
STUDY OF X-CHROMOSOME REGULATION DURING OOGENESIS IN MOUSE
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DOI：
10.1016/0014-4827(78)90251-3
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发表时间：
1978-01-01
影响因子：
3.7
通讯作者：
ANDINA, RJ
中科院分区：
文献类型：
--
作者：
ANDINA, RJ
与体细胞不同，哺乳动物的成熟卵母细胞有两条活跃的X染色体。这种情况可能通过两种可能的机制之一出现。在X失活之前，生殖系可能与体细胞分化。或者，生殖细胞中的X染色体在先前失活后会被重新激活。提出了与生殖细胞中X的再激活相容的数据；比较了XX和XO胎鼠卵母细胞中的x连锁酶。G6PD[葡萄糖-6-磷酸脱氢酶]的活性在两类细胞减数分裂早期相似，但后期XX/XO比接近2:1；这表明G6PD基因座的再激活。对于HPRT[次黄嘌呤磷酸核糖基转移酶]，在所有减数分裂阶段都观察到2:1的比例。HPRT在减数分裂早期表现出大量的酶活性增加，而G6PD则没有。这种酶在减数分裂早期的合成可能解释了这些数据与G6PD之间的差异，并将X再激活的时间置于减数分裂的开始。
Mature oocytes of mammals, in contrast to somatic cells, have 2 active X chromosomes. This situation might arise through either of 2 possible mechanisms. The germ line might be differentiated from somatic cells prior to X inactivation. Alternatively, an X chromosome in germ cells would be reactivated after prior inactivation. Data compatible with reactivation of the X in germ cells is presented; X-linked enzymes were compared in oocytes of XX and XO fetal mice. The activity of G6PD [glucose-6-phosphate dehydrogenase] is similar in the 2 classes of cells at early meiotic stages, but an XX/XO ratio of 2:1 is approached at later times; this suggests reactivation of the G6PD locus. For HPRT [hypoxanthine phosphoribosyl transferase], a 2:1 ratio is observed at all meiotic stages. HPRT shows a large increase in enzyme activity during early meiosis, while G6PD does not. Synthesis of this enzyme at early meiotic stages probably accounts for differences between these data and those obtained for G6PD, and places the time of X reactivation at the entry to meiosis.