Zhao A Z, Vansant G, Bell J, Humphreys T, Maxson R
Department of Biochemistry, University of Southern California School of Medicine, Los Angeles 90033.
Mech Dev. 1991 Mar;34(1):21-8. doi: 10.1016/0925-4773(91)90088-n.
The L1 late H2B histone gene of the sea urchin Strongylocentrotus purpuratus is transcriptionally activated in late blastula stage embryos by a mechanism that depends on an enhancer element located 3' of the gene (Zhao et al., 1990). A protein factor, designated H2B abp 1, binds this element at a site that resembles the consensus recognition sequence of Antennapedia-class homeodomain proteins. We demonstrate here that Antennapedia (Antp) and Hbox4 proteins, members of the Antennapedia class of homeoproteins from Drosophila and sea urchin respectively, bind the L1 H2B abp 1 site, and that the Drosophila Antp protein acts through this site to trans-activate the L1 H2B gene, in vivo. In addition, RNA gel blot analysis demonstrated that Hbox4 transcripts accumulate in developing embryos with a time course that closely resembles that of H2B adp 1 DNA binding activity and the activity and the transcription rate of the L1 late H2B gene. Finally, we show that antibody prepared against the sea urchin Hbox4 protein, a member of the Abd-B subclass of the Antennapedia class, specifically inhibits binding of the H2B abp 1 factor to the L1 H2B enhancer, suggesting that H2B abp 1 is encoded by Hbox4 or a closely related gene.
紫球海胆（Strongylocentrotus purpuratus）的L1晚期组蛋白H2B基因在囊胚晚期胚胎中通过一种依赖于位于该基因3'端的增强子元件的机制被转录激活（Zhao等人，1990年）。一种名为H2B abp 1的蛋白质因子在一个类似于触角足类同源结构域蛋白共有识别序列的位点结合该元件。我们在此证明，分别来自果蝇和海胆的触角足类同源蛋白成员触角足蛋白（Antp）和Hbox4蛋白结合L1 H2B abp 1位点，并且果蝇的Antp蛋白在体内通过该位点反式激活L1 H2B基因。此外，RNA凝胶印迹分析表明，Hbox4转录本在发育中的胚胎中积累，其时间进程与H2B adp 1 DNA结合活性以及L1晚期H2B基因的活性和转录速率密切相似。最后，我们表明，针对海胆Hbox4蛋白（触角足类Abd - B亚类的成员）制备的抗体特异性抑制H2B abp 1因子与L1 H2B增强子的结合，这表明H2B abp 1由Hbox4或密切相关的基因编码。
