|ZFIN ID: ZDB-PUB-060302-2|
Tandem-Repeated Zebrafish zp3 Genes Possess Oocyte-Specific Promoters and Are Insensitive to Estrogen Induction
Liu, X., Wang, H., and Gong, Z.
|Source:||Biology of reproduction 74(6): 1016-1025 (Journal)|
|Registered Authors:||Gong, Zhiyuan, Liu, Xingjun, Wang, Hai|
|Keywords:||Ovary, Developmental biology, Estradiol, Gene regulation, Oocyte development|
|PubMed:||16481590 Full text @ Biol. Reprod.|
Liu, X., Wang, H., and Gong, Z. (2006) Tandem-Repeated Zebrafish zp3 Genes Possess Oocyte-Specific Promoters and Are Insensitive to Estrogen Induction. Biology of reproduction. 74(6):1016-1025.
ABSTRACTZona pellucida (ZP) proteins are glycoprotein 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 weeks post fertilization, which was about five weeks earlier than the initial vtg1 expression, indicating that the ovary development was earlier than vitellogenesis. Both zp2 and zp3 mRNAs were expressed specifically in early growing oocytes and are insensitive to estrogen induction. As zp3 genes are organized in tandem repeats, in order to investigate whether an individual zp3 promoter is capable of driving oocyte-specific expression, 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.