CYTOKINESIS AND CYTOCHALASIN-INDUCED FURROW REGRESSION IN FIRST-CLEAVAGE ZYGOTE OF XENOPUS-LAEVIS
CYTOKINESIS AND CYTOCHALASIN-INDUCED FURROW REGRESSION IN FIRST-CLEAVAGE ZYGOTE OF XENOPUS-LAEVIS
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DOI：
10.1007/bf00330921
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发表时间：
1971-01-01
期刊：
影响因子：
--
通讯作者：
BLUEMINK, JG
中科院分区：
文献类型：
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作者：
BLUEMINK, JG
本文研究了非洲爪蟾（Xenopus laevis）第一次卵裂受精卵的卵裂和细胞松弛素效应。沟道的形成是膜表面收缩、连接形成和新膜向内生长共同作用的结果。在收缩阶段，镧结合渗出物沉积在沟隙中。这种物质分布在分散的斑块（约200 μ m）中，产生一个“毛刺”表面，覆盖着交错的细胞突起。在突起相遇的地方，它们形成160 μ m宽的粘附连接，暂时固定收缩的犁沟。在收缩期结束时（这最终导致卵裂平面内卵直径减少15%），沟底下100 μ m的细丝层被新膜的局部向内生长分裂，细丝占据横向位置。沟内生长通过两侧插入新膜进行，应用7.5 μg/ml细胞松弛素B（CCB）可导致沟回退而不阻断收缩性。CCB主要作用于细胞表面，仅间接作用于微丝系统。它干扰细胞连接的形成和扰乱沟向内生长。在没有稳定的160 μ m宽的粘附连接的情况下，新膜向外生长而不是向内生长。结果进行了讨论，参考其他膜不稳定剂，如磷脂酶C诱导的犁沟回归。比较显示，CCB还有助于插入新的细胞膜。为了解释细胞松弛素的生物学效应，提出了另一种工作假设，它满足了反对细胞松弛素B特异性干扰细微丝的概念。
The egg cleavage and the cytochalasin effect has been investigated in the first-cleavage zygotes ofXenopus laevis.—Furrow formation results from the joint action of surface constriction, junction formation, and ingrowth of new membrane. During the constriction phase lanthanum-binding exudate is deposited in the furrow gap. This material is distributed in dispersed patches (Ø 200 Å) giving rise to a “bur” surface which coats interdigitating cell protrusions. At places where protrusions meet they form 160 Å wide adherent junctions which provisionally fix the contracted furrow. At the end of the constriction phase (which ultimately accounts for 15 per cent of the reduction in egg diameter in the plane of cleavage) the layer of 100 Å filaments beneath the furrow bottom is split by local ingrowth of new membrane, and the filaments take up lateral positions. Furrow ingrowth proceeds by bilateral insertion of new membrane.The application of 7.5 μg/ml cytochalasin B (CCB) leads to furrow regression without blocking contractility. CCBprimarilyaffects the cell surface, and onlyindirectlyaffects the microfilament system. It interferes with cell junction formation and deranges furrow ingrowth. In the absence of stable 160 Å wide, adherent junctions the new membrane grows outwards instead of inwards. The results are discussed with reference to furrow regression induced by other membrane-destabilizing agents such as phospholipase C. Comparison reveals that CCB in addition facilitates the insertion of new cell membrane—. To interpret the biological effects of cytochalasin an alternative working hypothesis is presented, which meets the objections that can be raised against the concept that cytochalasin B specifically interferes with thin microfilaments.