小鼠SN和NSN卵成熟分裂过程中S1核酸酶敏感性变化

摘要： 比较了两种染色质构型不同的小鼠卵泡卵子体外成熟过程中S1核酸酶敏感性的变化。结果发现，染色质构型不同的两类小鼠卵子在第1次减数分裂中期（MⅠ期）S1核酸酶的敏感性存在显著差异，NSN(non-surrounded nucleolus，染色质结构较松散，散布在核质中)型卵子S1核酸酶的敏感性显著高于SN(surrounded nucleolus，染色质高度凝集，集中围绕在核仁周围，形成染色质环)型卵子（P <0.01）；然而在第2次减数分裂中期（MⅡ期）两种类型卵子S1核酸酶的敏感性趋于一致，二者无显著差异（P >0.05）。染色质构型不同的两种卵子发育至MⅠ期时，染色体单链构型丰富度存在显著差异，但由MⅠ期发育到MⅡ期过程中，二者单链构型丰富度趋于一致。

S1 Nuclease Sensitivity of Surrounded Nucleolus(SN)- and Non Surrounded Nucleolus(NSN)-type Mouse Ooctyes during In vitro Maturation

Abstract: The fully grown mouse germinal vesicle oocytes from large antral follicle can be classified into two groups, according to their chromatin configuration. The S1 nuclease sensitivity of them was investigated during their maturation in vitro. The results showed that NSN-type (non-surrounded nucleolus, whose decondensed chromatin distributed in almost whole nuclear) oocytes at MⅠ stage had more S1 nuclease sensitivity than that of SN-type (surrounded nucleolus，whose condensed chromatin surrounded nucleolus.) oocytes (P <0.01), while little difference between them in S1 nuclease sensitivity was found at MⅡ stage (P >0.05). It seemed that the NSN-type oocytes at MⅠ stage had more abundant single-strand property than SN-type oocytes, and during developing from MⅠ stage to MⅡ stage, the abundance of single-strand character in these two-type oocytes became homogenized.