Nakamura Takuma, Shiomi Inori, Shimizu Takashi
Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan.
Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan; Department of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan.
Gene Expr Patterns. 2017 Nov;25-26:29-35. doi: 10.1016/j.gep.2017.05.001. Epub 2017 May 4.
We have cloned and characterized the expression of a novel maternal gene festina lente (designated Ttu-fel) from the clitellate annelid Tubifex tubifex. Northern blot analyses have shown that Ttu-fel mRNA is approximately 8 kbp in length and that its expression is restricted to oocytes undergoing maturation division and early embryos up to 22-cell stage. Maternal transcripts of Ttu-fel are first detected in oocytes in the ovary of young adults (ca. 40 days after hatching); its expression continues in growing oocytes in the ovisac. Ttu-fel mRNA is distributed broadly throughout the egg undergoing maturation divisions. During the process of ooplasmic segregation that results in the pole plasm formation, Ttu-fel mRNA becomes concentrated to the animal and vegetal poles. The RNA in the animal hemisphere is distributed in a gradient with highest concentration in the cortical region. During the first two cleavages, Ttu-fel mRNA is segregated to CD cell then to D cell; it is subsequently inherited by the three D quadtrant micromeres, 1d, 2d and 3d. Around the time of transition to 22-cell stage, Ttu-fel mRNA becomes undetectable throughout the embryo.
我们已经从环节动物颤蚓中克隆并鉴定了一个新的母源基因festina lente（命名为Ttu-fel）的表达。Northern印迹分析表明，Ttu-fel mRNA长度约为8kbp，其表达仅限于经历成熟分裂的卵母细胞和直至22细胞期的早期胚胎。Ttu-fel的母源转录本首先在年轻成虫（孵化后约40天）卵巢中的卵母细胞中检测到；其表达在卵囊中生长的卵母细胞中持续存在。Ttu-fel mRNA广泛分布于经历成熟分裂的卵中。在导致极质形成的卵质分离过程中，Ttu-fel mRNA集中于动物极和植物极。动物半球的RNA呈梯度分布，皮质区域浓度最高。在前两次卵裂过程中，Ttu-fel mRNA先分离到CD细胞，然后到D细胞；随后由三个D象限小分裂球1d、2d和3d继承。在过渡到22细胞期前后，整个胚胎中无法检测到Ttu-fel mRNA。
