Tandem-repeated zebrafish zp3 genes possess oocyte-specific promoters and are insensitive to estrogen induction
Tandem-repeated zebrafish zp3 genes possess oocyte-specific promoters and are insensitive to estrogen induction
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DOI：
10.1095/biolreprod.105.049403
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发表时间：
2006-06-01
影响因子：
3.6
通讯作者：
Gong, Zhiyuan
中科院分区：
文献类型：
--
作者：
Liu, Xingjun;Wang, Hai;Gong, Zhiyuan
透明带 (Zp) 蛋白是鱼绒毛膜中的糖蛋白，由多个基因家族编码，包括 zp1、zp2、zp3 和潜在的其他 zp 基因。硬骨鱼中 zp 基因的表达要么在雌激素诱导下的肝脏中，要么在卵巢中表达。在本研究中，我们分离并表征了斑马鱼 zp3 基因组克隆，发现了三个具有高序列同一性的串联重复 zp3 基因。我们估计单倍体基因组中有 10-15 个 zp2 和 17-21 个 zp3 基因。我们还发现了一些变异的zp2和zp3亚科，每个亚科可能有多个成员。这些zp2和zp3基因分布在几个不同的染色体上。 zp2和zp3 mRNA的个体发育表达在受精后3周首次检测到，比最初的vtg1表达早约5周，表明卵巢发育早于卵黄发生。 zp2 和 zp3 mRNA 均在早期生长的卵母细胞中特异性表达，并且对雌激素诱导不敏感。由于 zp3 基因以串联重复形式组织，为了研究单个 zp3 启动子是否能够驱动卵母细胞特异性表达，使用 3.8 kb zp3 5' 上游区域培育了绿色荧光蛋白 (gfp) 转基因斑马鱼，我们发现 gfp 报告基因在 zp3:gfp 转基因雌性的发育卵母细胞中忠实表达。因此，新的转基因系不仅为监测雌性性腺发育提供了方便的活标记，而且证明单个zp3基因启动子足以进行卵母细胞特异性转录。
Zona pellucida (Zp) proteins are glycoproteins in fish chorion and are encoded by multiple gene families, including zp1, zp2, zp3, and potentially other zp genes. Expression of zp genes in teleosts is either in the liver under the induction of estrogen or in the ovaries. In the present study, we isolated and characterized a zebrafish zp3 genomic clone and found three tandem-repeated zp3 genes with high sequence identities. We estimated that there were 10-15 zp2 and 17-21 zp3 genes in a haploid genome. We also found some variant zp2 and zp3 subfamilies, and each subfamily may have multiple members. These zp2 and zp3 genes are distributed in several different chromosomes. Ontogenetic expression of zp2 and zp3 mRNAs was first detected at 3 wk postfertilization, which was about 5 wk earlier than initial vtg1 expression, indicating that ovary development was earlier than vitellogenesis. Both zp2 and zp3 mRNAs were expressed specifically in early-growing oocytes and are insensitive to estrogen induction. Because zp3 genes are organized in tandem repeats, to investigate whether an individual zp3 promoter is capable of driving oocyte-specific expression, green fluorescence protein (gfp)-transgenic zebrafish were developed by using a 3.8-kb zp3 5' upstream region, and we found that the gfp reporter gene was faithfully expressed in developing oocytes in zp3:gfp transgenic females. Thus, the new transgenic line not only provided a convenient living marker for monitoring female gonad development, but also demonstrated that a single zp3 gene promoter is sufficient for oocyte-specific transcription.