Department of Biology, University of Central Florida, Orlando, FL 32816, USA.
Dev Biol. 2010 Apr 15;340(2):249-55. doi: 10.1016/j.ydbio.2010.01.026. Epub 2010 Feb 1.
The Strongylocentrotus purpuratus polyketide synthase gene (SpPks) encodes an enzyme required for the biosynthesis of the larval pigment echinochrome. SpPks is expressed exclusively in pigment cells and their precursors starting at blastula stage. The 7th-9th cleavage Delta-Notch signaling, required for pigment cell development, positively regulates SpPks. In previous studies, the transcription factors glial cell missing (SpGcm), SpGatae and kruppel-like (SpKrl/z13) have been shown to positively regulate SpPks. To uncover the structure of the Gene Regulatory Network (GRN) regulating the specification and differentiation processes of pigment cells, we experimentally analyzed the putative SpPks cis-regulatory region. We established that the -1.5kb region is sufficient to recapitulate the correct spatial and temporal expression of SpPks. Predicted DNA-binding sites for SpGcm, SpGataE and SpKrl are located within this region. The mutagenesis of these DNA-binding sites indicated that SpGcm, SpGataE and SpKrl are direct positive regulators of SpPks. These results demonstrate that the sea urchin GRN for pigment cell development is quite shallow, which is typical of type I embryo development.
紫色海胆聚酮合酶基因（SpPks）编码一种酶，该酶对于幼虫色素海胆色素的生物合成是必需的。SpPks 仅在从囊胚期开始的色素细胞及其前体细胞中表达。对于色素细胞发育所必需的第 7-9 次分裂 Delta-Notch 信号正向调节 SpPks。在先前的研究中，已经表明神经胶质细胞缺失（SpGcm）、SpGatae 和 Krüppel 样（SpKrl/z13）转录因子正向调节 SpPks。为了揭示调节色素细胞特化和分化过程的基因调控网络（GRN）的结构，我们通过实验分析了假定的 SpPks 顺式调控区。我们确定-1.5kb 区域足以重现 SpPks 的正确时空表达。预测的 SpGcm、SpGataE 和 SpKrl 的 DNA 结合位点位于该区域内。这些 DNA 结合位点的突变表明 SpGcm、SpGataE 和 SpKrl 是 SpPks 的直接正向调节因子。这些结果表明，海胆色素细胞发育的 GRN 相当浅，这是 I 型胚胎发育的典型特征。
