Bates W R, Nishida H
Bamfield Marine Station, British Columbia, Canada.
Zoolog Sci. 1998 Feb;15(1):69-76. doi: 10.2108/zsj.15.69.
The developmental roles of factors associated with the nuclear complex of Halocynthia roretzi and Boltenia villosa oocytes were investigated by cutting mature oocytes into animal and vegetal merogons before and during GVBD. Animal and vegetal merogons were cultured in sea water until the GV cytoplasm had dispersed within the cytoplasm of control oocytes and then they were cross-fertilized and scored for their ability to undergo normal development. Halocynthia oocyte fragments produced from the animal region of oocytes containing intact GVs exhibited a low frequency of polyspermy, a high frequency of fertilization and cleavage, and a high frequency of expressing an epidermal antigen, Epi-2. In contrast, merogons produced from the vegetal region of Halocynthia oocytes in which GVs were intact exhibited a high frequency of polyspermy, did not undergo cell division, and expressed a high frequency of Epi-2 expression. When vegetal fragments were produced after the dispersal of approximately 50-70% of the GV nucleoplasm, these merogons exhibited a low frequency of polyspermy, high frequencies of cell division (including the formation of epidermal layer), and in most cases expressed Epi-2. Vegetal Boltenia fragments produced during GVBD in some cases developed into larvae. These results suggest that the ascidian GV nucleoplasm may contain factors required for fertilization and cell division and that epidermal determinants reside in the oocyte cytoplasm.
通过在生发泡破裂（GVBD）之前和期间将成熟的柄海鞘（Halocynthia roretzi）和藤壶海鞘（Boltenia villosa）卵母细胞切成动物极和植物极半卵，研究了与卵母细胞核复合体相关的因子的发育作用。将动物极和植物极半卵在海水中培养，直到生发泡（GV）细胞质在对照卵母细胞的细胞质中扩散，然后进行杂交受精，并对它们进行正常发育能力的评分。从含有完整GV的卵母细胞的动物区域产生的柄海鞘卵母细胞片段显示多精入卵频率低、受精和分裂频率高，以及表皮抗原Epi-2表达频率高。相反，从柄海鞘卵母细胞的植物区域产生的、其中GV完整的半卵显示多精入卵频率高，不进行细胞分裂，并且Epi-2表达频率高。当在大约50-70%的GV核质扩散后产生植物极片段时，这些半卵显示多精入卵频率低、细胞分裂频率高（包括表皮层的形成），并且在大多数情况下表达Epi-2。在GVBD期间产生的藤壶海鞘植物极片段在某些情况下发育成幼虫。这些结果表明，海鞘GV核质可能含有受精和细胞分裂所需的因子，并且表皮决定因素存在于卵母细胞细胞质中。
