Lassiter Christopher S, Kelley Betty, Linney Elwood
Duke University Program in Genetics, Duke University Medical Center, Box 3020 DUMC, Durham, NC 27710, USA.
Gene. 2002 Oct 16;299(1-2):141-51. doi: 10.1016/s0378-1119(02)01050-8.
Estrogenic steroid hormones mediate complex actions important in both embryonic and adult life. The hormones signal through ligand-inducible transcription factors known as estrogen receptors (ERs). In this study, we have isolated a zebrafish estrogen receptor with homology to human estrogen receptor beta (ERbeta). This zebrafish ERbeta (ERbetaa) has a conserved genomic structure of eight coding exons with boundaries similar to those of human ERbeta. The coding exon structures of two other zebrafish estrogen receptors (ERalpha and ERbetab) are presented as well. We also analyzed 3.3 kb of the promoter region and identified numerous putative transcription factor binding sites, including SP1 and ER half sites. Zebrafish ERbetaa message RNA is maternally loaded, but quickly degraded after fertilization, as detected by reverse transcriptase polymerase chain reaction. ERbetaa transcripts are detected again between 24 and 48 h post fertilization. These results indicate that ERbeta has been highly conserved during evolution and is likely used during later embryogenesis in zebrafish. Future identification of the expression levels and patterns of this and other estrogen receptors in zebrafish will allow a better understanding of estrogen signaling during embryogenesis.
雌激素类固醇激素介导着在胚胎期和成年期都很重要的复杂作用。这些激素通过被称为雌激素受体（ERs）的配体诱导型转录因子发出信号。在本研究中，我们分离出了一种与人类雌激素受体β（ERβ）具有同源性的斑马鱼雌激素受体。这种斑马鱼ERβ（ERβa）具有由八个编码外显子组成的保守基因组结构，其边界与人类ERβ的边界相似。另外两种斑马鱼雌激素受体（ERα和ERβb）的编码外显子结构也已给出。我们还分析了3.3 kb的启动子区域，并鉴定出许多假定的转录因子结合位点，包括SP1和ER半位点。通过逆转录聚合酶链反应检测发现，斑马鱼ERβa信使RNA是母源性加载的，但在受精后迅速降解。在受精后24至48小时之间再次检测到ERβa转录本。这些结果表明，ERβ在进化过程中高度保守，并且可能在斑马鱼后期胚胎发育过程中发挥作用。未来对斑马鱼中这种及其他雌激素受体的表达水平和模式的鉴定，将有助于更好地理解胚胎发育过程中的雌激素信号传导。
